A Novel Inner Time and Outer pH-Dependent Dual Coated Multi-Particulate Approach for Colon Specific Delivery of Ibuprofen Beyond Ileocecal Segment in Reduced Colonic Bacterial Diversity

A Novel Inner Time and Outer pH-Dependent Dual Coated Multi-Particulate Approach for Colon Specific Delivery of Ibuprofen Beyond Ileocecal Segment in Reduced Colonic Bacterial Diversity | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article A Novel Inner Time and Outer pH-Dependent Dual Coated Multi-Particulate Approach for Colon Specific Delivery of Ibuprofen Beyond Ileocecal Segment in Reduced Colonic Bacterial Diversity Debaprasad Ghosh, Nikhil Kumar Singh, Ashu Mittal, Deepti Katiyar, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8691710/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The purpose of the current novel study is to develop dual-coated multi-particulates with a combination of time-dependent inner and pH-dependent outer coating layers to control the release of the entrapped drug from the ascending colon onwards. Ibuprofen-loaded pellets prepared via powder layering technology were coated initially with time-dependent hydroxypropyl cellulose and ethyl cellulose-based inner polymeric layers and afterwards with the Eudragit L100 and Eudragit S100 based outer pH-dependent coating layers and evaluated. The best double coated batch showed nominal in vitro release of 6.163 ± 0.227% in simulated upper GI conditions, with surface morphology collaborating with kinetics data. In-vivo animal X-Ray Roentgenography and plasma analysis studies revealed intact multi-particulates arriving inside the colon with maximum plasma concentration of 5.97 ± 0.41 µg/ml (C max ), retarded till 12th hr (T max ). Results suggest that these dual-coated multi-particulates can be more efficient for colon specific targeting of various potent drugs. Ibuprofen colon targeted drug delivery Eudragit L100 Eudragit S100 hydroxypropyl cellulose ethyl cellulose Figures Figure 1 Figure 2 Figure 3 Figure 4 1. Introduction A successful colon-targeted drug delivery system (CTDDS) requires delivering maximum amount of drug inside the colon while preventing the early premature release of the drug in upper gastrointestinal tract (GIT). These dosage forms need to transit through the challenging upper GI environment of varying pH, transit time and presence of various physiological and gut bacterial enzymes [ 1 ]. CTDDSs become more important for various potent drugs such as anti-cancer drugs for the treatment of colonic cancers, whose premature release in the upper GIT can cause several adverse effects [ 2 – 4 ]. Protein and peptide-based drugs are also vulnerable for degradation by the proteolytic enzymes present in the upper GIT, and therefore colon-specific release of such drugs can mitigate such limitations [ 5 , 6 ]. Several nonsteroidal anti-inflammatory drugs (NSAIDS) causing gastric irritation also have been targeted for colonic release not only to prevent such adverse effects but also against localized colonic diseases such as irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and Crohn’s disease [ 7 ]. Several strategies have been utilized to successfully target drugs in the colon including pH-sensitive, GI transit time-dependent, and colonic microbial enzymatically degradable coatings over tablets or multi-particles or osmotically triggered approaches with each having their own advantages and limitations [ 8 , 9 ]. The major challenges include pH variations throughout the GIT, gastric retention time, varying GI transit time due to fed and fasted conditions, physiological and gut microbial enzymes. The stomach has the pH of 1-3.5 (average 1.2-2) in unfed conditions and 4.3–5.4 in fed conditions with an average transit time of 2 hr. The proximal part of the small intestine which includes the duodenum and jejunum have the pHs of 5–7 and 6–7 respectively (average 6-6.5) and transit time of 0.26 hr and 1.7 hr respectively. The distal small intestine has the pH of 6.6–7.4 and transit time of 1.3 hr. This makes the average small intestinal pH 6.8 and average transit time of 3 hr. In the initial part of the large intestine, particularly in the cecum, a sudden drop of pH (5.7–6.4) can be observed due the production of short chain fatty acids like butyrate, propionate, and acetate from the microbial fermentation of indigestible complex carbohydrate polysaccharides. The human cecum has a transit time of 4.5 hr. Afterwards a rise in pH can be observed as we further proceed through the ascending, transverse and the descending parts of the colon till the rectum from 6.4-8 with a transit time or 11-13.5 hr [ 10 ]. This sudden drop in pH from the 6.6–7.4 in ileum to 5.4 in cecum creates a great challenge in developing gastrointestinal pH-triggered CTDDSs as these dosage forms are generally made from pH-sensitive polymeric coatings designed to release the drug at pH of 6.8 to pH 7.4 and ends up releasing the drug in ileum. The variation in gastric retention time due to fed and unfed conditions, type of meal, feeding frequency and caloric content can also make any time-dependent polymer coated formulation that has been designed to release the drug after a certain point of time to release the either prematurely or too late. Certain diseases like IBD, colon cancer, and ulcerative colitis can delay the peristaltic movement inside the GIT. These diseases and various other factors such as food habits, ethnicity, differences in population and age can also reduce the colonic microflora diversity which can make complex polysaccharide-based colonic bacterial enzyme triggered approaches unsuitable for efficient colon targeting. In previous studies, coated multi-particulates have been found to be less impacted by gastric retention and delayed peristaltic movement compared to coated unit dosage forms such as tablets. The chances of dose dumping are also less in multi-particulates [ 8 ]. The current novel approach is based on the hypothesis that drug loaded multi-particulates with double layer of coatings over them where each layer is controlled by different triggering mechanisms can be more efficient for colon targeting. For this reason, the drug loaded multi-particulates in the current study have been initially coated with time-dependent hydroxypropyl cellulose and inert ethyl cellulose based mixed polymeric layer with varying coating thickness and then with Eudragit S100 and Eudragit L100 based, pH-dependent outer layer also with varying coating thicknesses to make the trial batches. The ratio of the used polymers in their respective coating solutions had also been varied to optimize the best batch. The coating thicknesses were measured by theoretical percentage of weight gain (%-TWG). Here it is assumed that the outer pH-dependent layer will ensure the safe transit of these coated multi-particulates through the lower pH environment of stomach and proximal small intestine and will disintegrate at the higher pH of the later part of the distal small intestine (pH 7.4). The disintegration of the outer layer will then expose the inner time-dependent layer either inside or at the end of the ileum. This inner time-dependent layer will then start to disintegrate from either inside the ileum or upon reaching the cecum as per the applied coating thicknesses. This should further prevent the release of the drug for the next 5 hr till the drug loaded pellets reach the ascending colon. From the ascending colon onwards, the drug should get released to effectively target these areas for localized and site-specific colonic diseases. In case of any failure of outer pH-dependent layer or any sudden rise in pH in upper GIT causing premature dissolving of outer layer, the inner layer should be able to retard the premature release of the drug for 5 hr which can be sufficient for the multi-particulates to safely transit either through the entirety of stomach and small intestine i.e., the upper GIT and reach the cecum or at least reach the end of the small intestine minimizing the chances of drug exposure of the upper GIT. The purpose of the current study was to develop a very site-specific, pH and time dual trigger controlled, colonic microbial enzyme independent CTDDS for any drug which either requires maximum colonic localization or can cause upper GI irritation. In the current study, ibuprofen had been used as a model drug [ 11 ]. It is a nonsteroidal anti-inflammatory drug (NSAID) used in the management of various conditions such as inflammatory diseases and in mild to moderate pains but causes upper GI irritation [ 12 ]. Ibuprofen drug-loaded pellets were prepared by using the powder layering technology and subsequently dual coatings were applied. Any possible drug-polymer interactions were analysed by using FT-IR (Fourier transformed infrared spectroscopy) and DSC (differential scanning calorimetry) study techniques. The dual coated multi-particulates were evaluated by various in vitro studies including percentage drug entrapment, percentage loose surface crystal studies, particle size distribution by sieve analysis, compressibility and flowability by Carr’s index and Hausner ratio, in vitro drug dissolution with and without simulated colonic microflora, in vitro drug release and release kinetics, and pellet surface morphology by SEM (scanning electron microscopy) studies. In vivo X-ray roentgenography and plasma analysis were conducted on New Zealand white rabbits to examine the colon targeting efficiency of the best batch [ 12 – 14 ]. 2. Materials and Methods 2.1 Materials The drug Ibuprofen (IBU), anti-sticking agent talc and binder polyvinylpyrrolidone (PVP) K-30D were purchased from Central Drug House, India. Polymers Eudragit S100 and L100, hydroxypropyl cellulose (HPC-HXF), ethyl cellulose Ethocel 45 cps (EC 45), probiotic biomix-I, and nonpareil sugar seeds (#30) were generously gifted by Evonik India, Ashland India, Colorcon Asia, Unique Biotech India, and Signet Chemical India, respectively. FTM (fluid thioglycolate media) and the plasticizer DBP (dibutyl phthalate) were purchased from Himedia Laboratories. Solvents methanol, ethanol, acetone, and isopropyl alcohol (Changshu Hongsheng Fine Chemicals, China) were purchased from the market. All chemicals used in the study were of analytical grade. White Albino New Zealand rabbits were obtained from the Rodent Research India Pvt Ltd., Jind district, Haryana, India. 2.2 Methods 2.2.1 Preparation of standard curve by UV-visible spectrophotometry 100 mg of IBU was weighed and dissolved in 100 ml of ethanol inside a volumetric flask (1000 µg/ml). From this stock solution, further serial dilutions were made to obtain various concentrations. The dilutions were made using either distilled water, simulated gastric fluid (SGF) of pH 1.2 (0.1N HCl) without enzymes, simulated small intestinal fluid (SSIF) of pH 6.8 phosphate buffer without enzymes, or simulated colonic fluid (SCF) of pH 7.4 phosphate buffer without enzymes separately. The absorbance of these dilutions was measured using a UV-visible spectrophotometer (Shimadzu UV 1800 Pharmaspec). The concentrations and the corresponding absorbances were plotted to prepare the standard curves of IBU in various simulated fluids [ 15 ]. 2.2.2 Drug Polymer Interaction Study 2.2.2.1 FT-IR (Fourier transform infrared) spectroscopy study FT-IR spectra of IBU, separate polymers, and the drug-polymer mixture in equal ratio were obtained from the FT-IR spectrometer (IRAffinity-1, Shimadzu, Japan) utilizing the KBr disc method. All samples were scanned individually in the wave number range of 4000 − 500 cm⁻¹. The characteristic FT-IR peaks of the functional groups present in the drug and polymer molecules were noted, analysed, and interpreted to detect drug-polymer compatibility [ 16 ] . 2.2.2.2 DSC (Differential scanning calorimetry) study The DSC study was performed to further demonstrate drug-polymer compatibility. The DSC thermographs of individual polymers, pure IBU, and an equal ratio of drug-polymer physical mixture were acquired using the PYRIS 6 DSC (PerkinElmer, USA). All powder samples were separately heated inside a sealed aluminium pan at the range of 30–400°C and at the rate of 10° C per minute with a 20 ml/min nitrogen gas flow. All system-generated DSC thermographs were recorded and interpreted [ 17 , 18 ]. 2.2.3 Preparation of the binder solution PVP K30, 5 gm, was accurately weighed and added into a mixed solvent of 70 ml of isopropyl alcohol and 30 ml of distilled water. A solution was made by mixing on a magnetic stirrer with a magnetic bead (Remi) overnight prior to use [ 19 ]. 2.2.4 Preparation of drug coated pellets The powder layering technique as developed, established, and published by Vuppala M et al. (1997) and Varshosaz J et al. (2009) was used to prepare the drug-loaded pellets of IBU with minor modifications [ 20 – 22 ]. The process parameters and specifications as later optimized and published by Majumdar et al. (2011) were maintained throughout the process [ 19 ]. Inert non-pareil sugar seeds with a mesh size of 30 were first dried at a temp of 40°C and then used to prepare the IBU-loaded pellets. The dried core seeds were placed inside the coating pan after applying the anti-sticking agent talc (5% w/w of the dry weight of the drug) on the inner surface of the coating pan. The binder solution was gently sprayed over the core seeds using a spray gun attached to an air compressor to wet the seeds sufficiently enough to adhere the IBU (powder layering technique). The pan (12” diameter and at a 40° angle of inclination) was continuously rotated (20 RPM) to ensure even distribution and adherence of the drug powder on the wetted pellets. Proper control of the coating bed temperature at 35°C via a hot air of 40°C and the aeration rate (10 cfm through an attached blower of 40 mm diameter) were maintained inside the pan to ensure the absence of over drying that can cause the drug to detach from the inner sugar seeds. This might have impacted the quality of the final product. The process is continued until the dry powder adheres properly to the pellets. The drug-to-seed ratio was kept at 1:4. The IBU-loaded pellets were dried inside the pan for another 30 min post-loading under 40°C hot air to evaporate the residual moisture[ 23 ]. 2.2.5 Preparation of coating solutions 2.2.5.1 Preparation of the time dependent coating solution The time-dependent coating solutions were prepared by mixing the polymers HPC-HXF and EC 45 in various ratios as described in Table 1 . The accurately weighed polymers were dissolved in a mixed solvent of ethanol and IPA (1:4). The solvent mix was previously plasticized with DBP (6% w/w of the total dry weight of the polymers). The coating solution was homogenized by overnight mixing on a Remi magnetic stirrer with a magnetic bead before use [ 23 , 24 ]. Table 1 Composition of Time-Dependent coated pellets [ 25 ]. S. No Formulation Code HPC-HXF: EC 45 Dry weight of polymers (gm) Plasticizer (6%w/w) (gm) TWG (%) HPC-HXF EC-45 1. F Tm1 1:1 0.5 0.5 0.06 5 2. F Tm2 1:1 0.5 0.5 0.06 10 3. F Tm3 1:1 0.5 0.5 0.06 15 4. F Tm4 1:1 0.5 0.5 0.06 20 5. F Tm5 1:2 0.5 1 0.09 5 6. F Tm6 1:2 0.5 1 0.09 10 7. F Tm7 1:2 0.5 1 0.09 15 8. F Tm8 1:2 0.5 1 0.09 20 9. F Tm9 1:3 0.5 1.5 0.12 5 10. F Tm10 1:3 0.5 1.5 0.12 10 11. F Tm11 1:3 0.5 1.5 0.12 15 12. F Tm12 1:3 0.5 1.5 0.12 20 13. F Tm13 1:4 0.4 1.6 0.12 5 14. F Tm14 1:4 0.4 1.6 0.12 10 15. F Tm15 1:4 0.4 1.6 0.12 15 16. F Tm16 1:4 0.4 1.6 0.12 20 2.2.5.2 Preparation of pH-dependent coating solution The pH-dependent coating solutions were prepared by mixing the polymers Eudragit L100 and Eudragit S100 in various ratios as described in Table 2 . The accurately weighed polymers were dissolved in a mixed solvent of acetone and IPA (1:1). The solvent was previously mixed with DBP (density: 1.05 gm/ml) at 2% w/w of the total dry weight of the polymers. The coating solution was homogenized by overnight mixing on a Remi magnetic stirrer with a magnetic bead before use [ 23 , 26 ]. Table 2 Composition of pH-dependent coated pellets [ 25 ]. Sr. No Formulation Code Eudragit L 100: Eudragit S 100 Weight of polymers Plasticizer (2%w/w) (gm) TWG (%) Eudragit S 100 (gm) Eudragit L 100 (gm) 1. F pH1 1:1 5 5 0.2 5 2. F pH2 1:1 5 5 0.2 10 3. F pH3 1:1 5 5 0.2 15 4. F pH4 1:1 5 5 0.2 20 5. F pH5 1:3 2.5 7.5 0.2 5 6. F pH6 1:3 2.5 7.5 0.2 10 7. F pH7 1:3 2.5 7.5 0.2 15 8. F pH8 1:3 2.5 7.5 0.2 20 9. F pH9 1:4 2 8 0.2 5 10. F pH10 1:4 2 8 0.2 10 11. F pH11 1:4 2 8 0.2 15 12. F pH12 1:4 2 8 0.2 20 13. F pH13 2:3 4 6 0.2 5 14. F pH14 2:3 4 6 0.2 10 15. F pH15 2:3 4 6 0.2 15 16. F pH16 2:3 4 6 0.2 20 17. F pH17 3:1 7.5 2.5 0.2 5 18. F pH18 3:1 7.5 2.5 0.2 10 19. F pH19 3:1 7.5 2.5 0.2 15 20. F pH20 3:1 7.5 2.5 0.2 20 21. F pH21 3:2 6 4 0.2 5 22. F pH22 3:2 6 4 0.2 10 23. F pH23 3:2 6 4 0.2 15 24. F pH24 3:2 6 4 0.2 20 25. F pH25 4:1 8 2 0.2 5 26. F pH26 4:1 8 2 0.2 10 27. F pH27 4:1 8 2 0.2 15 28. F pH28 4:1 8 2 0.2 20 During the stirring, the lids of the containers were frequently removed for a very short duration to expel the pressure generated by the accumulated solvent vapor inside, and the volume of the solutions was again maintained by adding the mixed solvents used. 2.2.6. Preparation of coated pellets 2.2.6.1 Preparation of Time dependent and pH dependent single coated pellets The uncoated IBU-loaded pellets were used to first prepare the single-coated multi-particulate batches of various coating thicknesses measured in the form of theoretical percentage of weight gain (%-TWG). Different ratios of mixed HPC-HXF and EC 45-based time-dependent mixed polymeric coating solutions were applied over the uncoated pellets, with each solution again at various coating levels of 5%, 10%, 15%, and 20% TWG (Table 1 ) to prepare the time-dependent trial batches. All coated pellets were dried for 1 hr at 40°C to remove the solvent residues [ 24 ]. The ratio of HPC-HXF and EC 45 as well as their corresponding coating thickness was optimized by in vitro dissolution study, and the polymeric ratio of the best batch was then used to formulate the dual-coated trial batches. Similarly, pH-dependent single-coated multi-particulate batches were prepared by coating uncoated IBU-loaded pellets with pH-dependent mixed polymeric solutions of Eudragit L100: Eudragit S100 at different ratios and coating thicknesses as mentioned in Table 2 . The coated multi-particulates were then dried for 1 hr at 40°C to remove the residual solvent. The ratio of Eudragit L100 and Eudragit S100 and their corresponding coating thickness was optimized by in vitro dissolution study, and the polymeric ratio of the best batch was then used to formulate the dual-coated trial batches [ 21 , 27 ]. 2.2.6.2 Preparation of inner time and outer pH dependent dual coated pellets Double coating was achieved by coating the uncoated IBU-loaded pellets initially with an optimized ratio of time-dependent mixed polymeric solution (inner coating layer) and, after drying them at 40°C for 1 hr, the next layer of pH-dependent coating (outer coating layer) was applied and again dried at 40°C for an hour. Both inner and outer layers were applied again at different coating thicknesses to prepare the dual-coated trial batches (Table 3 ) for further optimization by in vitro dissolution [ 28 ]. Table 3 Composition of inner time dependent and outer pH dependent dual coated pellets. Formulation Code. Inner time-dependent coating Outer pH-dependent coating HPC-HXF: EC 45 %-TWG Eudragit L100: Eudragit S100 %-TWG F D1 1:4 5% 3:2 5% F D2 5% 10% F D3 F D4 F D5 F D6 F D7 F D8 F D9 F D10 F D11 F D12 F D13 F D14 F D15 F D16 1:4 1:4 1:4 5% 5% 10% 10% 10% 10% 15% 15% 15% 15% 20% 20% 20% 20% 3:2 3:2 3:2 15% 20% 5% 10% 15% 20% 5% 10% 15% 20% 5% 10% 15% 20% 2.2.7 Percentage drug entrapment efficiency (%-DEE) Single- or dual-coated multi-particulates containing 100 mg of IBU theoretically were crushed with the aid of a mortar and pestle and mixed with 100 ml of ethanol to form a slurry. The slurry was centrifuged for 15 min at 3000 rpm and filtered. The filtrate was diluted with distilled water and analyzed using a UV-visible spectrophotometer at a predetermined wavelength (221 nm) to determine the %-drug entrapment efficiencies. The following equation was used for the calculation of %-DEE [ 29 ]. Drug Entrapment Efficiency = (Practical absorbance / Standard absorbance) x100 2.2.8 Percentage loose surface crystals (%-LSC) In separate 100 ml volumetric flasks, coated pellets from each trial batch containing theoretically equivalent to 100 mg of IBU were taken, and the volume was made up to 100 ml with SCF (pH 7.4 phosphate buffer). The flasks were shaken vigorously for 5 minutes to allow any crystalline loose drug adhered to the coated surface to leach out from the suspended multi-particulates into the SCF. The SCF medium of each corresponding trial batch was further diluted and evaluated at 221 nm in a UV-visible spectrophotometer. The absorbance data for each trial batch were used to determine the percentage of loose surface crystals of IBU present on the surface of the coated pellets [ 19 , 30 ]. 2.2.9 Micromeritic Characterization of coated pellets Standard sieve analysis was used to determine the particle size and particle size distribution (PSD) of each batch of coated pellets as per the published protocol of Shah et al. (2024), and the PSD data has been presented graphically [ 31 ]. Percentage compressibility and relative flowability of the coated multi-particulates were obtained by calculating the Carr’s compressibility index and the Hausner ratio from the bulk densities and tapped densities of coated pellets from each trial batch. The data was tabulated, analysed, and compared[ 32 ]. The following formularies were used. Carr’s Compressibility Index (%) = (Tapped Density -Bulk Density)/Tapped Density*100 Hausner Ratio =Tapped Density/Bulk Density 2.2.10 In vitro drug release, drug release kinetic study and mean dissolution time The in vitro drug release studies of trial batches were carried out using a USP Type 1 in vitro drug dissolution testing apparatus at 100 rpm, maintained at a temperature of 37.0 ± 0.5°C. Multi-particulates containing an equivalent of a 400 mg dose of IBU were taken from each trial batch based upon the %-DEE and were studied first in 900 ml of SGF (pH 1.2) for the initial 2 hours, then in 900 ml of SSIF (pH 6.8) for another 3 hours, and finally in SCF (pH 7.4) for an additional 7 hours. As the main object of the current study is to rely on GI transit time and pH variations to trigger the colonic release of the drug beyond ileocecal segment irrespective of colonic microflora diversity and enzymes, neither human faecal nor animal faecal or caecal content nor pro-biotic bacterial cultures in FTM nor any colonic bacterial enzyme such as pectinase were added. Later the best single and dual coated batches were reassessed in vitro using probiotic biomix-I previously incubated in FTM and then added in the SCF to simulate colonic microbial conditions in vitro as per the biorelevant animal sparing published protocols of Singh S. et al. (2015) and Yadav A. et al. (2017) [ 33 , 34 ]. The data was later compared and analysed. Throughout the in vitro dissolution process, samples of 5 ml were withdrawn at predetermined time intervals using a sample ejector and replaced with 5 ml of fresh corresponding buffer to maintain the sink condition. The concentration of IBU in each sample was determined using the UV-visible spectrophotometer. The cumulative percentage of drug release data and the corresponding time intervals were used to understand the mechanism of drug release and drug release kinetics from the coated multi-particulate pellets. These data were plotted in various mathematical models like zero-order, first-order, Higuchi, and Korsmeyer-Peppas models to obtain the best fit [ 35 – 38 ]. To determine the efficiency of the polymeric coatings in retarding the release of IBU in the simulated upper gastrointestinal (GI) conditions and to assess the characteristics of the rate of drug release through these polymeric coatings on the coated pellets, MDT (mean dissolution time) of all trial batches was calculated using the equation mentioned below [ 39 – 41 ]. MDT = (n/n + 1). K − 1/n [ 42 ] 2.2.11 Surface morphology by Scanning electron microscopy (SEM) The surface topography of coated pellets was studied using SEM. Samples from uncoated pellets and coated pellets showing the best colon targeting efficiency prior to and post in vitro dissolution were taken to study the effects of polymeric coatings over uncoated surfaces and the effects of simulated GI fluids on the polymeric coatings. The samples were attached to a stub with a double-sided tape coated with a thin layer of gold using a sputter coater. The coated samples were then observed under the scanning electron microscope (Zeiss GeminiSEM 300, Germany) at various magnifications, and images were taken for further analysis [ 43 ]. 2.2.12 Statistical analysis One-way and Two-way ANOVA were used to statistically analyse and compare the in vitro drug release from the various formulation trial batches utilising the GraphPad Prism statistical software. A probability level value of less than 0.05 ( p < 0.05) was regarded as statistically significant [ 44 ]. Based on the data obtained from the statistical analysis, the best double coated trial batch was selected and the colon targeting efficiency of the statistically significant batch was further evaluated in in vivo conditions using New Zealand white rabbits. 2.2.13 In vivo animal study conditions The animal study protocol (IAEC/KSOP/2023-24/16, dated 18/11/2023) was duly approved by the Institutional Animal Ethical Committee of KIET School of Pharmacy, Ghaziabad, India, which is registered with CCSEA (Reg. no. 1099/PO/Re/S/07/CPCSEA). All in vivo animal studies in living animals must adhere to the guidelines laid down by the CCSEA (Committee for Control and Supervision of Experiments on Animals) in India and need to follow the OECD (Organization for Economic Co-operation and Development) test guidelines. These guidelines, rules, and regulations are at par with the international standards like EU Directive 2010/63/EU, the National Research Council's Guide for the Care and Use of Laboratory Animals, the ARRIVE guidelines (National Centre for the Replacement, Refinement, and Reduction of Animals in Research), and the U.K. Animals (Scientific Procedures) Act, 1986 [ 45 ]. Several previously published protocols involving in vivo evaluation of CTDDSs have highlighted the benefits of using New Zealand white rabbit-based models, including adequate belly size for imaging techniques, ease of administration of multi-particulates via the oral route, and the possibility for the collection of sufficient amounts of blood for plasma analysis. Thus, New Zealand white rabbits were used for the in vivo X-ray roentgenography study and in vivo animal plasma analysis study [ 46 , 47 ]. 2.2.13.1 In vivo X-ray Roentgenography study Twelve well-acclimatized white New Zealand rabbits of either sex (average weight 3 ± 0.5 kg) were taken and divided into two groups of six animals each as trial and control groups. The animals were fasted overnight prior to study and allowed only water. The coated multi-particulate batch showing the best colon targeting efficiency as per the statistical analysis was again freshly prepared, but the entrapped IBU inside was replaced with the X-ray contrasting agent barium sulphate (BaSO 4 ). The non-toxic radiopaque BaSO 4 is generally used to obtain the X-ray images of the GI tract, as it is generally considered safe and does not get absorbed through the GIT [ 48 ]. Coated pellets suspended in 10 ml of distilled water were orally fed to the animals of the trial group, whereas the other group was kept as the control. A high-frequency X-ray machine (GME 500), set at 4 MAS and 50 KV, was used to capture the X-ray roentgenography images of coated pellets transversing through the GIT at predetermined time intervals, and these abdominal scans were later studied to determine the efficiency of the colon-targeted coated multi-particulates [ 49 , 50 ]. 2.2.13.2 In vivo plasma analysis Previously established methods by YILIMAZ B. et al. (2009) and Rachmawati, Heni, et al. (2012) were adopted to perform the in vivo plasma analysis with minor modifications. Properly acclimatized, twelve white albino New Zealand rabbits (of either sex) were taken and divided into two groups of six animals each. The animals were 4–6 months of age with 2.5 to 3.5 kg of bodyweight. One group was kept as a control while the other group was used for the trials. The animals in both groups were fasted for 12 hr overnight prior to the study with access to only water. The freshly prepared, best-performing, dual-coated formulation batch and uncoated pellets, both carrying an equivalent animal dose of 20 mg/kg of IBU [ 32 , 33 ], were administered via the oral route into the rabbits in the trial group using a polyethylene cannula of 2 mm diameter along with 1 ml of distilled water. The rabbits in the control group were given water only. No food was allowed during the study, but the animals were allowed to freely move inside the cage with access to plenty of drinking water. The concentrations of IBU in plasma were ascertained in the Agilent 1120 Compact reversed-phase HPLC (high-performance chromatography) with a C18 column (HC-C18(2) Column, 4.6 x 150 mm, 5 µm, 400 bar). At previously determined specific time points, i.e., just before the oral administration (0 hr) and at 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 15, and 18 hr post oral administration, about 1 ml of blood samples were collected from the marginal ear veins of the rabbits in heparinized tubes, vortexed immediately for 1 min, and centrifuged at 10,000xg for 10 min. The separated plasma samples were transferred inside the microcentrifuge tubes. From these 0.2 mL plasma samples, aliquots were taken into separate glass tubes with Teflon-lined caps. 0.6 mL of acetonitrile was added into each of the aliquots and vortexed for 5 min, followed by centrifugation at 10,000xg for 5 min. The obtained organic supernatant layers were again transferred into another 5 ml tube and dried by evaporation under the stream of nitrogen (N 2 ) gas at 40ºC. The dried residues were redissolved in 0.2 mL of mobile phase, vortexed for 1 min, and then centrifuged for 3 min at 10,000 xg. Aliquots of 0.02 ml from each sample were injected into the HPLC system to determine the IBU concentration in the rabbit plasma at various time intervals. The mobile phase used was composed of 20 mM phosphate buffer (pH 7) and acetonitrile (60:40, v/v) with 0.1% trifluoroacetic acid (TFA). The filtered mobile phase was pumped at a 1 ml/min flow rate. The eluent was monitored using a UV detector at 221 nm. Naproxen was used as an internal standard (IS). After a 15-day washing-out period, in vivo plasma analysis for the uncoated IBU pellets was performed similarly and compared with the previous result of the dual-coated pellets [ 11 , 51 ]. The mean plasma concentrations of IBU in rabbits following the oral administration of best performing batch (F D16 ) and the uncoated drug loaded pellets were plotted alongside their corresponding time points and analysed. 3. Results and Discussions 3.1 UV-visible spectrophotometry study and standard calibration curve The λ max of IBU was obtained at 221 nm (Figure 1a). All standard curves plotted in various simulated GI fluids as mentioned above were found to be linear and followed Beer-Lambert’s law at the concentration range from 1 to 19 μg/ml (Figure 1b–1e) [52,53]. 3.2. FT-IR Study The FT-IR spectra of pure IBU, individual polymers, and drug polymer physical mixture (representing the best dual-coated batch) are displayed in Figure 1f to Figure 1k, respectively. The pure IBU showed its characteristic peaks at 3778.55 cm⁻¹ due to single bond O-H stretch, at 2630.91 cm⁻¹ for single bond C-H stretch, at 2943.37 cm⁻¹ for CH bending, and at 1226.73 cm⁻¹ and 2872 cm⁻¹ due to C-C and C-H groups. The iso-propionic acid group of IBU also had displayed the characteristic infrared band at 1718.58 cm⁻¹ of carbonyl stretching [54]. The FT-IR spectra of the drug-polymer physical mixture also showed similar characteristic peaks of IBU in its FTIR spectra without any major changes, and the remaining peaks due to the polymers used were also at par with the characteristic FT-IR spectra of pure polymers [54]. 3.3 DSC study DSC thermographs of the drug IBU and the polymers Eudragit L100, Eudragit S100, HPC-HXF, and EC45 (Figure 1l to 1q) showed endothermic peaks at 81.376°C, 92.887°C, 90.549°C, 132.716°C, and 139.199°C, respectively. The IBU present in the drug-physical mixture showed a minor shift in its endothermic peak at 79.607°C [55]. 3.4 Percentage drug entrapment efficiency The best single-coated time-dependent batch (FTm16) had a %-DEE of 95.06±0.69%. Similarly, the best pH-based single-coated formulation batch (FpH24) had shown a drug entrapment efficiency of 96.96±0.73%. Among all double-coated batches, the %-DEE had varied between 85.93±0.52% (FD16) and 96.77±0.67% (Table 4). 3.5 Loose surface crystal (LSC) study The best time-dependent (F Tm16 ) and pH-dependent (F pH24 ) batches had shown %-LSC of 1.154 ± 0.11% and 1.162 ± 0.09%, respectively. The best double-coated batch, F D16 , showed %-LCS of 0.746 ± 0.08%, and the %-LSC varied from 0.645 ± 0.05% to 1.123 ± 0.13% across all double-coated batches (Table 4). Table 4. Drug entrapment efficiency, loose surface crystal, micrometric properties of coated multi-particulates (n=3). 3.6 Micromeritic properties and Particle Size and Size Distribution (PSD) Most of the coated multi-particulates fell within the 1000 to 1300 µm particle size range, with PSD found to be varying between 69.53±0.16% and 80.58±0.09% in the #12 mesh size range across all dual-coated pellet batches (Figure 2). The Hausner ratio and the Carr’s compressibility index were determined for all coated multi-particulate batches using the respective tapped and bulk densities and are shown in Table 4. The best dual-coated batch showed an excellent Carr’s index value of 9.074±0.090 and a Hausner ratio of 1.100±0.02. 3.7. In vitro drug release study Upon analyzing the in vitro drug release from the single coated multi-particulate batches first had yielded the batches F pH24 (pH-dependent) and F Tm16 (time-dependent) to be with the best colon targeting potential in their respective classes. The batches F Tm16 and F pH24 had in vitro cumulative percentages of IBU release of 1.794±0.037% vs 2.727±0.052% in SGF, 12.873±2.157% vs 18.697±2.356% in SSIF and 85.773±6.654% vs 95.335±3.544% in SCF with MDTs of 17.4064 hr. vs 15.9866 hr. respectively. In both the time and pH-dependent categories, the single coated multi-particulates with 5%-TWG of coating thicknesses were unable to restrict the early release of IBU in simulated upper GI conditions in vitro and hence their data were not reported in this study. Thus, the polymeric ratio inside these batches were considered to prepare the dual coated multi-particulate batches. The best dual coated batch (F D16 ) had shown even lesser amount of IBU release i.e., up to 1.563±0.038% in SGF, up to 6.163±0.227% in SSIF and up to 96.637±4.361% in SCF. The best batch was able to localize almost 90% of the drug under in vitro simulated colonic conditions using GI pH and transit time. The best pH-dependent, time-dependent and dual coated multi-particulate batches were again sent for in vitro dissolution studies in the presence of colonic bacterial enzymatic environment simulated in vitro by the addition of biomix-I culture in FTM. The cumulative amount of IBU release in the simulated in vitro upper GI conditions was found to be lowest in the best dual coated batch. The use of biomix-I culture to artificially simulate the colonic microflora, and its enzymatic conditions is a biorelevant and animal sparing alternative that have already been established by Singh S. et al. 2015 [33]. Thus, the published protocol of Singh S. et al. 2015 and Yadav et al. 2017 were used to simulate the colonic bacterial enzymatic environment in vitro by adding FTM containing biomix-I culture in the SCF [34]. The cumulative percentage of IBU release from the best double-coated batch (F D16 ) in presence of simulated colonic microflora was found to be up to 1.671±0.042% in SGF (pH 1.2), up to 5.786±0.231% in SSIF (pH 6.8) and up to 97.108±4.47% in SCF (pH 7.4) with colonic microflora. Thus, the best dual coated F D16 batch was able to localize about 92% of IBU in presence of colonic microflora in SCF vs 90% of IBU in absence of colonic microflora in SCF depending solely on variations in GI pH and GI transit time (Figure 3 d). Thus, the batch F D16 had the lowest amount of IBU release in both SGF and SSIF amongst all double-coated batches and had been taken forward for the in vivo X-ray roentgenography and plasma analysis studies in New Zealand white rabbits for the further verification of its colon targeting efficiency under actual in vivo conditions. The cumulative percentage of IBU release from all trial batches is shown in Table 5 as well as graphically represented in Figure 3. 3.8 Drug release kinetics and the MDT (mean dissolution time) All under trial single and double coated formulation batches including the best dual coated batch F D16 had followed zero order drug release model with Korsmeyer-Peppas super case-II transports mechanism (n>1). The highest mean dissolution time of 29.319 hr was observed in case of the best dual coated batch F D16 . The drug release kinetics data including MDT for all trial batches has been reported in Table 5. 3.9 Statistical analysis The difference in in vitro IBU release from the single coated F TM16 , F pH24 , and dual coated F D16 batches in SGF was found to statistically non-significant ( p = 0.1605) using One-way Anova. Two-way Anova also yielded same non-significant p values in SGF (Row factor p =0.1228, column factor p =0.0663). But, one-way Anova has yielded a significant difference between the cumulative percentages in in vitro IBU releases between the best dual coated F D16 batch and the selected single coated (F TM16 and F pH24 ) batches in SSIF ( p = 0.0100) at its 5 th hr end point. In Two-way Anova, the differences between them were also significant (Row factor p =0.0346, column factor p =0.0021) in SSIF. Two-way Anova test of amount of IBU release from the above-mentioned batches in SCF had shown a significant difference (Row factor p <0.0001, column factor p =0.0447) in favour of the dual coated formulation batch. 3.10 The surface topography of coated Pellets Captured surface images of the pellets by SEM at various stages of their preparation and evaluation, with each having unique surface topography has been reported in Figure 1r to Figure 1u. SEM surface images of uncoated pellets just after drug loading (1r), up on the application of inner time-dependent coating layer (1s), after the outer pH-dependent coating layer (1t) before subjecting them to the in-vitro dissolution studies and after going through the in-vitro dissolution studies (1u) had provided a detailed outlook on their surface topographies. 3.12.1. In vivo X-Ray Roentgenography At specific predetermined time intervals of 1.5 hr., 3.5 hr., 4 hr., and 7 hr., X-ray Roentgenographic images were captured for the orally fed statistically significant batch F D16 to monitor the GI transit behavior of the double coated BaSO 4 loaded pellets through the stomach, small intestine, and colon in vivo . Despite containing a small amount of X-ray opaque material BaSO 4 , the coated pellets became visible in the X-ray images (Figure 4a to 4d). Table 5. Comparative data of percentage drug release, drug-release kinetics and mean dissolution time of trial batches (n=6). Formulation SGF SSIF SCF Zero Order Model First Order Model Higuchi Model Korsmeyer- Peppas Model MDT Code (2 hr) (5 hr) (12 hr) r2 k r2 k r2 k r2 k n (hr.) F Tm16 1.794±0.037 12.873±2.157 94.563±6.654 0.889 8.933 0.758 0.173 0.770 33.292 0.9852 0.007260 2.05292 17.4064 F pH24 2.727±0.052 18.697±2.356 98.475±3.544 0.948 10.612 0.795 0.261 0.862 40.538 0.8431 0.007905 2.24269 15.9866 F D1 2.065±0.012 13.161±0.102 99.362±4.112 0.870 8.833 0.529 0.104 0.751 32.088 0.9910 0.00730 2.01760 17.6568 F D2 1.796±0.021 12.569±0.116 99.232±3.112 0.881 9.456 0.621 0.103 0.762 34.377 0.9852 0.00553 2.02126 18.7563 F D3 1.447±0.051 11.681±0.654 98.319±4.117 0.855 8.893 0.638 0.086 0.730 32.124 0.9900 0.00380 2.02907 20.4418 F D4 1.016±0.037 10.156±0.741 97.161±4.223 0.809 7.981 0.585 0.073 0.678 28.553 0.9903 0.00278 2.02994 22.1575 F D5 1.824±0.025 12.125±0.417 99.361±3.745 0.878 9.273 0.612 0.100 0.753 33.586 0.9917 0.00387 2.02711 20.3786 F D6 1.607±0.039 11.174±0.645 98.150±4.325 0.866 8.850 0.626 0.086 0.739 31.961 0.9578 0.002298 2.03674 23.2447 F D7 1.604±0.048 10.355±0.517 97.676±4.256 0.855 8.390 0.611 0.077 0.726 30.228 0.9851 0.001801 2.03528 24.9576 F D8 1.569±0.049 9.442±0.389 96.154±3.745 0.841 7.965 0.607 0.069 0.711 28.633 0.9808 0.001409 2.04157 26.7265 F D9 2.133±0.135 12.714±0.524 98.747±4.521 0.859 8.775 0.602 0.089 0.733 31.687 0.9922 0.003500 2.03016 20.8595 F D10 1.819±0.471 11.279±0.448 97.613±4.113 0.849 8.359 0.601 0.078 0.721 30.107 0.9937 0.001703 2.04061 25.2630 F D11 1.613±0.055 10.069±0.617 96.135±4.117 0.808 7.741 0.560 0.069 0.675 27.658 0.9911 0.00128 2.04188 27.4927 F D12 1.567±0.047 8.049±0.423 95.828±3.776 0.779 7.381 0.552 0.063 0.644 26.228 0.9673 0.001125 2.05127 28.4124 F D13 1.990±0.042 11.262±0.515 99.565±4.256 0.866 8.777 0.649 0.083 0.740 31.727 0.9915 0.003337 2.03236 21.0867 F D14 1.811±0.045 10.340±0.603 98.739±4.223 0.849 8.285 0.658 0.072 0.721 29.840 0.9938 0.001546 2.04151 25.9838 F D15 1.930±0.044 9.734±0.417 97.512±4.569 0.835 7.749 0.645 0.063 0.705 27.823 0.9896 0.00125 2.04456 27.6739 F D16 1.563±0.038 6.163±0.227 96.637±4.361 0.763 7.017 0.593 0.055 0.627 24.879 0.9775 0.00104 2.04485 29.3190 3.12.2. In vivo Plasma analysis Figure 4e. represents the in vivo mean plasma concentration of IBU after oral administration of uncoated IBU-loaded pellets and dual-coated multi-particulates of the best-performing batch F D16 as per in vitro dissolution studies. According to the obtained data, a notable difference in C max and T max was observed between the uncoated and the double-coated formulation batches. At 4 th and 5 th hr, the mean plasma concentrations of IBU were 0.31±0.02 μg/ml and 0.38±0.02 μg/ml when, according to the X-ray roentgenography study, the coated multi-particles were inside the small intestine. Whereas at 6 th , 7 th , and 8 th hr the mean plasma concentrations of IBU were 0.48±0.02 μg/ml, 0.54±0.03 μg/ml, and 0.66±0.06 μg/ml, when the coated multi-particles would have been inside the cecum. At 9 th hr onwards a sudden increase in the mean plasma concentration of IBU was observed and the maximum mean plasma concentration (C max ) was found to be at 5.97±0.41 μg/ml for the best dual-coated batch (F D16 ) but was retarded till the 12 th hr (Tmax) of the study when the coated pellets would have been deep inside the colon. On the contrary, the uncoated IBU-loaded pellets had demonstrated the maximum mean plasma IBU concentration of 6.07±0.36 μg/ml, which was reached early at 2 nd hr (Tmax) of the study. The mean plasma concentrations of IBU gradually kept getting reduced thereafter at the end of the 18 th hr for both the batches. 4. Discussions The λ max of ibuprofen was obtained at 221 nm. All standard curves plotted were found to be linear and followed Beer- Lambert’s at a concentration range from 1–19 µg/ml [ 52 ]. Several characteristic peaks in the IBU's FT-IR spectra are representative of the compound's distinctive pharmacological activity and can interact with the polymers being used. The presence of similar FT-IR peaks in the drug-polymer physical mixture without any major shifts and absence of any new peaks indicates drug-polymer compatibility. The minor shift observed in the endothermic DSC thermograph peaks of IBU and the polymers in the drug-polymer physical mixture compared to their individual DSC thermographs can be due to exceedingly weak physical interactions between the polymers and drug, a phenomenon that is common in polymers-coated formulations. Lack of new peaks and significant shifts reflects drug-polymer compatibility [ 17 , 19 ]. Thus, the drug-polymer compatibility can be ensured from these results. PVP K30D in 5% w/v solution had sufficient activity as binder to adhere the powdered drug over the inert sugar seeds with over 85 %-DEE, ver negligible %-LSC (< 1.5%), and fair to excellent flow properties and compressibility as per Table 4 [ 22 , 26 ]. The concentration of the binder had not impacted the in vitro and in vivo release of IBU while minimizing the %-LSC which would have caused irregular drug release. These results collaborated with the previous studies using powder layering technology [ 13 , 20 – 22 ]. Figure 2 also indicates majority of the prepared coated pellets had lied within a uniform size range. These factors might be helpful in either incorporating the prepared coated pellets inside capsules or compressing them into tablets. Both the prepared coating solutions were found to be sprayable and were not too viscous (200–450 cp). An increase in EC 45 had slightly increased the viscosity of these solutions. As per the in vitro drug release data obtained, the best dual coated batch was able to minimize the release of IBU in simulated upper GI conditions while released maximum amount of the drug at pH 7.4 and after 5 hr in SCF in the absence of colonic microflora. The presence of colonic microflora had not impacted the release of IBU form the coated pellets as these bacteria only secretes enzymes to degrade complex polysaccharides and not the time- and pH-dependent polymers used in the current study. Thus, the release of the drug from the dual coated pellets were controlled by the pH and time. The SEM images had showed rough surface of uncoated pellets turned smoother with the application of successive coating layers (Fig. 1 r- 1 t). These images also indicate the swelling, erosion and degradation of polymeric coating layers post in vitro dissolution (Fig. 1 u) which corelates with the zero-order Korsmeyer-Peppas super case 2 transport model as seen in the drug release kinetic studies in Table 5 . The minimum IBU release in the upper GIT and maximum IBU release in the SCF was found be statistically significant in the best batch F D16 compared to all single and double coated trial batches. In vivo plasma analysis indicates almost negligible IBU in plasma in first 2 hr of the study indicating safe transit of the dual coated pellets through the stomach and initial parts of the intestine. The traces of IBU may be due to the loose surface crystals adhered on the surface of the coated pellets. A very negligible but increasing amount of IBU was found from the 2nd to 9th hr of the study which corelates with the increase in the pH as the coated pellets migrated through the small intestine. This might be attributed to the swelling of the polymeric coating layers as indicated by the drug release kinetics data suggesting Korsmeyer-Peppas super case 2 transport model. A sudden rise in the plasma concentration of IBU after 9th hr indicates degradation of inner time-dependent coating layer and release of the drug. The data also suggests between 2nd to 9th hr the outer pH-dependent layer had first degraded at higher distal small intestinal pH and then the exposed inner time-dependent layer was able to retard the maximum IBU release till 9th hr (Fig. 4 e) beyond the cecum. The X-ray roentgenography images also shows intact orally administered multi-particulates in stomach after 1.5 hr (Fig. 4 a), in small intestine after 3.5 hr (Fig. 4 b), transversing through the small intestine and ileocecal segment after 4 hr (Fig. 4 c) and started to reach colon from cecum after 7th hr (Fig. 4 d) still intact. After 9th hr post oral administration possible disintegration of coated multi-particulates inside the colon made them undetectable in the subsequent X-ray images thereafter. These X-ray images also collaborate with the in vivo plasma analysis data as the plasma IBU concentration was still very low between 6th to 9th hr and only had a sudden rise after 9th hr. The maximum release of IBU was observed between 9th and 15th hr with the maximum plasma concentration at 12th hr indicates maximum release of the drug inside the colon. This precise level of colon targeting was found to be relatively better than previous studies with single or double compression coated tablets, single coated multi-particulates or coated hot melt extruded pellets using either pH or GI transit time or combination of pH and colonic bacterial enzymes [ 39 , 40 , 56 – 58 ]. 5. Conclusion In conclusion, the potential of dual coated multi-particulates as effective CTDDS has been highlighted. A more precise colon specific release of drug was achieved with a double failsafe mechanism for early dose dumping. The FT-IR and DSC results show stability of IBU inside the polymeric coatings. Uniformity in PSD and higher amount of %-DEE indicates consisted performance of the dual coated pellets. Both in vitro and in vivo studies have highlighted the superior colon targeting efficiency of the dual coated pellets. Both the SEM and in vitro drug release kinetics studies highlighted the zero-order Korsmeyer-Peppas super case 2 transport model which attributes to the swelling, erosion or degradation of polymeric surface coatings. The above findings propose the prospects of inner time- and outer pH-dependent dual-coated preparations as a potentially promising approach for successful CTDDSs containing various other potent drugs, proteins, peptides and chemotherapeutic agents. Declarations Funding NA Author contributions Conceptualization-Debaprasad Ghosh & Ashu Mittal; Methodology- Debaprasad Ghosh & Deepti Katiyar; Validation and formal analysis- Sanjeev Kumar; Writing—original draft preparation- Nikhil Kumar Singh & Debaprasad Ghosh; review and editing- Vinay Kumar. All authors have read and agreed to the published version of the manuscript. Statement The Mendeley cite was used for arranging the references of this manuscript. The manuscript was reviewed, and content was edited as per the requirement. The authors take full responsibility for the content of this publication. Author statement The animal study was performed with proper approval and permission from the IAEC. Declaration of Competing Interest None Data availability The research data will be made available on request. Appendixes Not applicable Acknowledgement The authors acknowledge the valuable support from the KIET School of Pharmacy, Ghaziabad. References Chourasia MK, Jain SK. 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Compacted Multiparticulate Systems for Colon-Specific Delivery of Ketoprofen. AAPS PharmSciTech. 2017 Aug 10;18(6):2260–8. Bensouiki S, Belaib F, Sindt M, Magri P, Rup-Jacques S, Bensouici C, et al. Evaluation of Anti-inflammatory Activity and In Vitro Drug Release of Ibuprofen-Loaded Nanoparticles Based on Sodium Alginate and Chitosan. Arab J Sci Eng. 2020 Sep 27;45(9):7599–609. Vemula SK. Formulation and pharmacokinetics of colon-specific double-compression coated mini-tablets: Chronopharmaceutical delivery of ketorolac tromethamine. Int J Pharm. 2015 Aug;491(1–2):35–41. Vemula SK, Katkum R. Colon-specific double-compression coated pulsatile tablets of ketorolac tromethamine: Formulation development and pharmacokinetics. J Drug Deliv Sci Technol. 2015 Oct;29:78–83. Vemula SK, Narala S, Uttreja P, Narala N, Daravath B, Kalla CSA, et al. 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Development of biotin decorated Olaparib loaded cationic lipopolymeric hybrid nanoparticle and evaluation of its anticancer effect and pharmacokinetics for triple negative breast cancer. J Drug Deliv Sci Technol. 2024 Apr;94:105458. Patel MM, Amin AF. Design and Optimization of Colon-Targeted System of Theophylline for Chronotherapy of Nocturnal Asthma. J Pharm Sci. 2011 May;100(5):1760–72. Srivastava R, Kumar D, Pathak K. Colonic luminal surface retention of meloxicam microsponges delivered by erosion based colon-targeted matrix tablet. Int J Pharm. 2012 May;427(2):153–62. Donthi MR, Dudhipala NR, Komalla DR. Preparation and Evaluation of Fixed Combination of Ketoprofen Enteric Coated and Famotidine Floating Mini Tablets by Single Unit Encapsulation System. J Bioequivalence Bioavailab. 2015;07(06). Patel MM, Amin AF. Formulation and development of release modulated colon targeted system of meloxicam for potential application in the prophylaxis of colorectal cancer. Drug Deliv. 2011 May 7;18(4):281–93. Ghosh D, Mittal A, Arora MK. Effect of Source and Degree of Esterification of High Methoxyl Pectin on Oral Colon-Targeted Multiparticulated Delivery of Otilonium Bromide. ACS Omega. 2025 Aug 19;10(32):36481–95. YILMAZ B, ASCI A, PALABIYIK SS. Yüksek Performanslı Sıvı Kromatografisi Kullanarak Tavşan Plazmasında İbuprofenin Tayini. Kafkas Univ Vet Fak Derg. 2009; Das SK, Yuvaraja K, Khanam J, Nanda A. Formulation development and statistical optimization of ibuprofen-loaded polymethacrylate microspheres using response surface methodology. Chemical Engineering Research and Design. 2015 Apr;96:1–14. Bolourtchian N, Karimi K, Aboofazeli R. Preparation and characterization of ibuprofen microspheres. J Microencapsul. 2005 Aug 3;22(5):529–38. Andrew EC, Maduabuchi MV, Grace EA, Chidera AC, Pauline ON, Benjamin OK, et al. Preparation and In Vitro Evaluation of Ibuprofen Microspheres Using Ionic Gelation Method. Mathews Journal of Pharmaceutical Science. 2024 Nov 30;8(3). Abdul Wahab. Pre-formulation investigation and in vitro evaluation of directly compressed ibuprofen-ethocel oral controlled release matrix tablets: A kinetic approach. Afr J Pharm Pharmacol. 2011 Nov 22;5(19). Vemula SK, Narala S, Uttreja P, Narala N, Daravath B, Kalla CSA, et al. Quality by Design (QbD) Approach to Develop Colon-Specific Ketoprofen Hot-Melt Extruded Pellets: Impact of Eudragit® S 100 Coating on the In Vitro Drug Release. Pharmaceutics. 2024 Sep 27;16(10):1265. Gazzaniga A, Moutaharrik S, Filippin I, Foppoli A, Palugan L, Maroni A, et al. Time-Based Formulation Strategies for Colon Drug Delivery. Pharmaceutics. 2022 Dec 9;14(12):2762. Sandu MKR, Majumdar S, Chatterjee S, Mazumder R. Optimization and characterization of xanthan gum based multiparticulate formulation for colon targeting. Intelligent Pharmacy. 2024 Jun;2(3):339–45. Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8691710","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":595024628,"identity":"d840f805-963e-45a4-8fde-d1fccc61cf1e","order_by":0,"name":"Debaprasad Ghosh","email":"","orcid":"","institution":"KIET School of Pharmacy, KIET Group of Institutions","correspondingAuthor":false,"prefix":"","firstName":"Debaprasad","middleName":"","lastName":"Ghosh","suffix":""},{"id":595024639,"identity":"e09ba726-0009-456e-b1b7-a564d2708b5b","order_by":1,"name":"Nikhil Kumar Singh","email":"","orcid":"","institution":"KIET School of Pharmacy, KIET Group of Institutions","correspondingAuthor":false,"prefix":"","firstName":"Nikhil","middleName":"Kumar","lastName":"Singh","suffix":""},{"id":595024651,"identity":"bf42a6d6-33e3-446b-b0a9-eb4cf00fd0a2","order_by":2,"name":"Ashu Mittal","email":"","orcid":"","institution":"Teerthanker Mahaveer College of Pharmacy, Teerthanker Mahaveer University","correspondingAuthor":false,"prefix":"","firstName":"Ashu","middleName":"","lastName":"Mittal","suffix":""},{"id":595024658,"identity":"40ddab3b-3657-46a7-9b31-3490e2e3f7d0","order_by":3,"name":"Deepti Katiyar","email":"","orcid":"","institution":"KIET School of Pharmacy, KIET Group of Institutions","correspondingAuthor":false,"prefix":"","firstName":"Deepti","middleName":"","lastName":"Katiyar","suffix":""},{"id":595024665,"identity":"db969c16-6d62-4a63-87ed-32f8d7fee51c","order_by":4,"name":"Sanjeev Kumar","email":"","orcid":"","institution":"KIET School of Pharmacy, KIET Group of Institutions","correspondingAuthor":false,"prefix":"","firstName":"Sanjeev","middleName":"","lastName":"Kumar","suffix":""},{"id":595024667,"identity":"c5059cff-46ce-4bbe-b89f-d6cc956fab1e","order_by":5,"name":"Vinay Kumar","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABC0lEQVRIiWNgGAWjYDACZhBxAM61kAPzHxCt5QCDhDGYTiBoFZKWxAYQA58Wg+O8Bz/znDkczT/77MHPHyok0ueHHX4ItMVOTrcBh5bDfMnSPDcO5844l5csceCMRO7G22kGQC3JxmYHsGuRbOYxkOb5cDi34QyPgcTBNqCW2QkgLQcSt+HWYvwbpGX+GR7jHwf/SaQbzk7/gFcLPzOPGdhhG87wmEkcbJBIkJfOwW8LSIvlnDPpuRvP8KVZnDkmYbhBOqfgQIIBbr+w8Z8xvvHmmHXuvDO8h29U1NjIy89O3/zhQ4WdHC4tIMDEA6YgJIMBWKUBbuUgwPgDWYt8A37Vo2AUjIJRMPIAALP/ZZDUzUgpAAAAAElFTkSuQmCC","orcid":"","institution":"KIET School of Pharmacy, KIET Group of Institutions","correspondingAuthor":true,"prefix":"","firstName":"Vinay","middleName":"","lastName":"Kumar","suffix":""}],"badges":[],"createdAt":"2026-01-25 10:23:14","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8691710/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8691710/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":103216108,"identity":"5c2daeeb-56b9-448e-85c6-34db469f0c2a","added_by":"auto","created_at":"2026-02-23 09:30:25","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":302768,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eUV- visible spectrophotometry of\u003c/strong\u003e (a) Ibuprofen (IBU), standard curve of IBU (b) in distilled water, (c) in pH 1.2 SGF, (d) in pH 6.8 SSIF, (e) in pH 7.4 SCF. \u0026nbsp;FT-IR spectra of (f) Ibuprofen, (g) Eudragit S100, (h) Eudragit L100, (i) Hydroxypropyl cellulose (HPC HXF), (j) Ethyl cellulose (EC 45), (k) Drug polymer physical mixture. DSC thermographs of (l) Ibuprofen, (m) Hydroxypropyl cellulose (HPC HXF), (n) Ethyl cellulose (EC 45), (o) Eudragit L100, (p) Eudragit S100, (q) Drug polymer physical mixture\u003cem\u003e. \u003c/em\u003eScanning electron microscopy images of the best dual coated formulation (r) Uncoated drug laded pellets, (s) Pellets coated with HPC HXF and EC 45 time dependent first polymeric layer, (t) Pellets coated with Eudragit L100 and Eudragit S100 based pH dependent second polymeric coating layer before \u003cem\u003ein-vitro\u003c/em\u003edissolution, (u) Double coated pellets after \u003cem\u003ein vitro\u003c/em\u003e dissolution. (v) Chemical structure of Ibuprofen, (w) diagram of human GIT.\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-8691710/v1/1734a5b6fbfcae01e68da79a.png"},{"id":103505695,"identity":"bc6c176d-9689-4824-8761-d9b46530d318","added_by":"auto","created_at":"2026-02-26 13:32:39","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":25633,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eParticle size distribution of different formulation batches (n=3).\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"22.png","url":"https://assets-eu.researchsquare.com/files/rs-8691710/v1/747cc9c1a22a31c704c0f1aa.png"},{"id":103216109,"identity":"28fce810-3698-41bf-8911-86a89d08b735","added_by":"auto","created_at":"2026-02-23 09:30:25","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":472221,"visible":true,"origin":"","legend":"\u003cp\u003eComparative \u003cem\u003eIn vitro\u003c/em\u003e drug release studies of formulation batches: (a) all single coated time-dependent batches, (b) all single coated pH-dependent batches, and (c) all inner time and outer pH dependent double coated formulation batches in absence simulate colonic microflora. (d) Comparative \u003cem\u003eIn vitro\u003c/em\u003e drug release studies of best time-dependent, pH and double coated multi-particulate batches in presence of simulated colonic microflora \u003cem\u003ein vitro\u003c/em\u003e (n=6).\u003c/p\u003e","description":"","filename":"33.png","url":"https://assets-eu.researchsquare.com/files/rs-8691710/v1/db707c7121f2d697a2846cca.png"},{"id":103216111,"identity":"1b3d3060-7392-4ec0-b16f-7b954bd80e93","added_by":"auto","created_at":"2026-02-23 09:30:25","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":242276,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eUV- visible spectrophotometry of\u003c/strong\u003e (a) Ibuprofen (IBU), standard curve of IBU (b) in distilled water, (c) in pH 1.2 SGF, (d) in pH 6.8 SSIF, (e) in pH 7.4 SCF. \u0026nbsp;FT-IR spectra of (f) Ibuprofen, (g) Eudragit S100, (h) Eudragit L100, (i) Hydroxypropyl cellulose (HPC HXF), (j) Ethyl cellulose (EC 45), (k) Drug polymer physical mixture. DSC thermographs of (l) Ibuprofen, (m) Hydroxypropyl cellulose (HPC HXF), (n) Ethyl cellulose (EC 45), (o) Eudragit L100, (p) Eudragit S100, (q) Drug polymer physical mixture\u003cem\u003e. \u003c/em\u003eScanning electron microscopy images of the best dual coated formulation (r) Uncoated drug laded pellets, (s) Pellets coated with HPC HXF and EC 45 time dependent first polymeric layer, (t) Pellets coated with Eudragit L100 and Eudragit S100 based pH dependent second polymeric coating layer before \u003cem\u003ein-vitro\u003c/em\u003edissolution, (u) Double coated pellets after \u003cem\u003ein vitro\u003c/em\u003e dissolution. (v) Chemical structure of Ibuprofen, (w) diagram of human GIT.\u003c/p\u003e","description":"","filename":"44.png","url":"https://assets-eu.researchsquare.com/files/rs-8691710/v1/519eb7d6e4280ff5ccc3f5e2.png"},{"id":103509504,"identity":"a9bbd213-bbe4-4e9f-8dba-5f333cb95962","added_by":"auto","created_at":"2026-02-26 13:59:25","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2945739,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8691710/v1/cf1784e4-159a-469b-b5cc-bb2c58a5edd8.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"A Novel Inner Time and Outer pH-Dependent Dual Coated Multi-Particulate Approach for Colon Specific Delivery of Ibuprofen Beyond Ileocecal Segment in Reduced Colonic Bacterial Diversity","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eA successful colon-targeted drug delivery system (CTDDS) requires delivering maximum amount of drug inside the colon while preventing the early premature release of the drug in upper gastrointestinal tract (GIT). These dosage forms need to transit through the challenging upper GI environment of varying pH, transit time and presence of various physiological and gut bacterial enzymes [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. CTDDSs become more important for various potent drugs such as anti-cancer drugs for the treatment of colonic cancers, whose premature release in the upper GIT can cause several adverse effects [\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Protein and peptide-based drugs are also vulnerable for degradation by the proteolytic enzymes present in the upper GIT, and therefore colon-specific release of such drugs can mitigate such limitations [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Several nonsteroidal anti-inflammatory drugs (NSAIDS) causing gastric irritation also have been targeted for colonic release not only to prevent such adverse effects but also against localized colonic diseases such as irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and Crohn\u0026rsquo;s disease [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Several strategies have been utilized to successfully target drugs in the colon including pH-sensitive, GI transit time-dependent, and colonic microbial enzymatically degradable coatings over tablets or multi-particles or osmotically triggered approaches with each having their own advantages and limitations [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The major challenges include pH variations throughout the GIT, gastric retention time, varying GI transit time due to fed and fasted conditions, physiological and gut microbial enzymes. The stomach has the pH of 1-3.5 (average 1.2-2) in unfed conditions and 4.3\u0026ndash;5.4 in fed conditions with an average transit time of 2 hr. The proximal part of the small intestine which includes the duodenum and jejunum have the pHs of 5\u0026ndash;7 and 6\u0026ndash;7 respectively (average 6-6.5) and transit time of 0.26 hr and 1.7 hr respectively. The distal small intestine has the pH of 6.6\u0026ndash;7.4 and transit time of 1.3 hr. This makes the average small intestinal pH 6.8 and average transit time of 3 hr. In the initial part of the large intestine, particularly in the cecum, a sudden drop of pH (5.7\u0026ndash;6.4) can be observed due the production of short chain fatty acids like butyrate, propionate, and acetate from the microbial fermentation of indigestible complex carbohydrate polysaccharides. The human cecum has a transit time of 4.5 hr. Afterwards a rise in pH can be observed as we further proceed through the ascending, transverse and the descending parts of the colon till the rectum from 6.4-8 with a transit time or 11-13.5 hr [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. This sudden drop in pH from the 6.6\u0026ndash;7.4 in ileum to 5.4 in cecum creates a great challenge in developing gastrointestinal pH-triggered CTDDSs as these dosage forms are generally made from pH-sensitive polymeric coatings designed to release the drug at pH of 6.8 to pH 7.4 and ends up releasing the drug in ileum. The variation in gastric retention time due to fed and unfed conditions, type of meal, feeding frequency and caloric content can also make any time-dependent polymer coated formulation that has been designed to release the drug after a certain point of time to release the either prematurely or too late. Certain diseases like IBD, colon cancer, and ulcerative colitis can delay the peristaltic movement inside the GIT. These diseases and various other factors such as food habits, ethnicity, differences in population and age can also reduce the colonic microflora diversity which can make complex polysaccharide-based colonic bacterial enzyme triggered approaches unsuitable for efficient colon targeting. In previous studies, coated multi-particulates have been found to be less impacted by gastric retention and delayed peristaltic movement compared to coated unit dosage forms such as tablets. The chances of dose dumping are also less in multi-particulates [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe current novel approach is based on the hypothesis that drug loaded multi-particulates with double layer of coatings over them where each layer is controlled by different triggering mechanisms can be more efficient for colon targeting. For this reason, the drug loaded multi-particulates in the current study have been initially coated with time-dependent hydroxypropyl cellulose and inert ethyl cellulose based mixed polymeric layer with varying coating thickness and then with Eudragit S100 and Eudragit L100 based, pH-dependent outer layer also with varying coating thicknesses to make the trial batches. The ratio of the used polymers in their respective coating solutions had also been varied to optimize the best batch. The coating thicknesses were measured by theoretical percentage of weight gain (%-TWG). Here it is assumed that the outer pH-dependent layer will ensure the safe transit of these coated multi-particulates through the lower pH environment of stomach and proximal small intestine and will disintegrate at the higher pH of the later part of the distal small intestine (pH 7.4). The disintegration of the outer layer will then expose the inner time-dependent layer either inside or at the end of the ileum. This inner time-dependent layer will then start to disintegrate from either inside the ileum or upon reaching the cecum as per the applied coating thicknesses. This should further prevent the release of the drug for the next 5 hr till the drug loaded pellets reach the ascending colon. From the ascending colon onwards, the drug should get released to effectively target these areas for localized and site-specific colonic diseases. In case of any failure of outer pH-dependent layer or any sudden rise in pH in upper GIT causing premature dissolving of outer layer, the inner layer should be able to retard the premature release of the drug for 5 hr which can be sufficient for the multi-particulates to safely transit either through the entirety of stomach and small intestine i.e., the upper GIT and reach the cecum or at least reach the end of the small intestine minimizing the chances of drug exposure of the upper GIT.\u003c/p\u003e \u003cp\u003eThe purpose of the current study was to develop a very site-specific, pH and time dual trigger controlled, colonic microbial enzyme independent CTDDS for any drug which either requires maximum colonic localization or can cause upper GI irritation. In the current study, ibuprofen had been used as a model drug [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. It is a nonsteroidal anti-inflammatory drug (NSAID) used in the management of various conditions such as inflammatory diseases and in mild to moderate pains but causes upper GI irritation [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Ibuprofen drug-loaded pellets were prepared by using the powder layering technology and subsequently dual coatings were applied. Any possible drug-polymer interactions were analysed by using FT-IR (Fourier transformed infrared spectroscopy) and DSC (differential scanning calorimetry) study techniques. The dual coated multi-particulates were evaluated by various \u003cem\u003ein vitro\u003c/em\u003e studies including percentage drug entrapment, percentage loose surface crystal studies, particle size distribution by sieve analysis, compressibility and flowability by Carr\u0026rsquo;s index and Hausner ratio, \u003cem\u003ein vitro\u003c/em\u003e drug dissolution with and without simulated colonic microflora, \u003cem\u003ein vitro\u003c/em\u003e drug release and release kinetics, and pellet surface morphology by SEM (scanning electron microscopy) studies. \u003cem\u003eIn vivo\u003c/em\u003e X-ray roentgenography and plasma analysis were conducted on New Zealand white rabbits to examine the colon targeting efficiency of the best batch [\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Materials\u003c/h2\u003e \u003cp\u003eThe drug Ibuprofen (IBU), anti-sticking agent talc and binder polyvinylpyrrolidone (PVP) K-30D were purchased from Central Drug House, India. Polymers Eudragit S100 and L100, hydroxypropyl cellulose (HPC-HXF), ethyl cellulose Ethocel 45 cps (EC 45), probiotic biomix-I, and nonpareil sugar seeds (#30) were generously gifted by Evonik India, Ashland India, Colorcon Asia, Unique Biotech India, and Signet Chemical India, respectively. FTM (fluid thioglycolate media) and the plasticizer DBP (dibutyl phthalate) were purchased from Himedia Laboratories. Solvents methanol, ethanol, acetone, and isopropyl alcohol (Changshu Hongsheng Fine Chemicals, China) were purchased from the market. All chemicals used in the study were of analytical grade. White Albino New Zealand rabbits were obtained from the Rodent Research India Pvt Ltd., Jind district, Haryana, India.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Methods\u003c/h2\u003e \u003cdiv id=\"Sec5\" class=\"Section3\"\u003e \u003ch2\u003e2.2.1 Preparation of standard curve by UV-visible spectrophotometry\u003c/h2\u003e \u003cp\u003e100 mg of IBU was weighed and dissolved in 100 ml of ethanol inside a volumetric flask (1000 \u0026micro;g/ml). From this stock solution, further serial dilutions were made to obtain various concentrations. The dilutions were made using either distilled water, simulated gastric fluid (SGF) of pH 1.2 (0.1N HCl) without enzymes, simulated small intestinal fluid (SSIF) of pH 6.8 phosphate buffer without enzymes, or simulated colonic fluid (SCF) of pH 7.4 phosphate buffer without enzymes separately. The absorbance of these dilutions was measured using a UV-visible spectrophotometer (Shimadzu UV 1800 Pharmaspec). The concentrations and the corresponding absorbances were plotted to prepare the standard curves of IBU in various simulated fluids [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003e2.2.2 Drug Polymer Interaction Study\u003c/h2\u003e \u003cdiv id=\"Sec7\" class=\"Section4\"\u003e \u003ch2\u003e\u003cem\u003e2.2.2.1 FT-IR (Fourier transform infrared) spectroscopy study\u003c/em\u003e\u003c/h2\u003e \u003cp\u003eFT-IR spectra of IBU, separate polymers, and the drug-polymer mixture in equal ratio were obtained from the FT-IR spectrometer (IRAffinity-1, Shimadzu, Japan) utilizing the KBr disc method. All samples were scanned individually in the wave number range of 4000\u0026thinsp;\u0026minus;\u0026thinsp;500 cm⁻\u0026sup1;. The characteristic FT-IR peaks of the functional groups present in the drug and polymer molecules were noted, analysed, and interpreted to detect drug-polymer compatibility [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] .\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section4\"\u003e \u003ch2\u003e2.2.2.2 DSC (Differential scanning calorimetry) study\u003c/h2\u003e \u003cp\u003eThe DSC study was performed to further demonstrate drug-polymer compatibility. The DSC thermographs of individual polymers, pure IBU, and an equal ratio of drug-polymer physical mixture were acquired using the PYRIS 6 DSC (PerkinElmer, USA). All powder samples were separately heated inside a sealed aluminium pan at the range of 30\u0026ndash;400\u0026deg;C and at the rate of 10\u0026deg; C per minute with a 20 ml/min nitrogen gas flow. All system-generated DSC thermographs were recorded and interpreted [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003e2.2.3 Preparation of the binder solution\u003c/h2\u003e \u003cp\u003ePVP K30, 5 gm, was accurately weighed and added into a mixed solvent of 70 ml of isopropyl alcohol and 30 ml of distilled water. A solution was made by mixing on a magnetic stirrer with a magnetic bead (Remi) overnight prior to use [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e2.2.4 Preparation of drug coated pellets\u003c/h2\u003e \u003cp\u003eThe powder layering technique as developed, established, and published by Vuppala M et al. (1997) and Varshosaz J et al. (2009) was used to prepare the drug-loaded pellets of IBU with minor modifications [\u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. The process parameters and specifications as later optimized and published by Majumdar et al. (2011) were maintained throughout the process [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Inert non-pareil sugar seeds with a mesh size of 30 were first dried at a temp of 40\u0026deg;C and then used to prepare the IBU-loaded pellets. The dried core seeds were placed inside the coating pan after applying the anti-sticking agent talc (5% w/w of the dry weight of the drug) on the inner surface of the coating pan. The binder solution was gently sprayed over the core seeds using a spray gun attached to an air compressor to wet the seeds sufficiently enough to adhere the IBU (powder layering technique). The pan (12\u0026rdquo; diameter and at a 40\u0026deg; angle of inclination) was continuously rotated (20 RPM) to ensure even distribution and adherence of the drug powder on the wetted pellets. Proper control of the coating bed temperature at 35\u0026deg;C via a hot air of 40\u0026deg;C and the aeration rate (10 cfm through an attached blower of 40 mm diameter) were maintained inside the pan to ensure the absence of over drying that can cause the drug to detach from the inner sugar seeds. This might have impacted the quality of the final product. The process is continued until the dry powder adheres properly to the pellets. The drug-to-seed ratio was kept at 1:4. The IBU-loaded pellets were dried inside the pan for another 30 min post-loading under 40\u0026deg;C hot air to evaporate the residual moisture[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e \u003ch2\u003e2.2.5 Preparation of coating solutions\u003c/h2\u003e \u003cdiv id=\"Sec12\" class=\"Section4\"\u003e \u003ch2\u003e2.2.5.1 Preparation of the time dependent coating solution\u003c/h2\u003e \u003cp\u003eThe time-dependent coating solutions were prepared by mixing the polymers HPC-HXF and EC 45 in various ratios as described in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The accurately weighed polymers were dissolved in a mixed solvent of ethanol and IPA (1:4). The solvent mix was previously plasticized with DBP (6% w/w of the total dry weight of the polymers). The coating solution was homogenized by overnight mixing on a Remi magnetic stirrer with a magnetic bead before use [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cb\u003eComposition of Time-Dependent coated pellets\u003c/b\u003e [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eS. No\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eFormulation\u003c/p\u003e \u003cp\u003eCode\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eHPC-HXF: EC 45\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eDry weight of polymers (gm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003ePlasticizer\u003c/p\u003e \u003cp\u003e(6%w/w)\u003c/p\u003e \u003cp\u003e(gm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eTWG\u003c/p\u003e \u003cp\u003e(%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHPC-HXF\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eEC-45\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF\u003csub\u003eTm1\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF\u003csub\u003eTm2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF\u003csub\u003eTm3\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e 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colname=\"c7\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF\u003csub\u003eTm5\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF\u003csub\u003eTm6\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF\u003csub\u003eTm7\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e8.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF\u003csub\u003eTm8\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e9.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF\u003csub\u003eTm9\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF\u003csub\u003eTm10\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e11.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF\u003csub\u003eTm11\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e12.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF\u003csub\u003eTm12\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e13.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF\u003csub\u003eTm13\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e14.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF\u003csub\u003eTm14\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e15.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF\u003csub\u003eTm15\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e16.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF\u003csub\u003eTm16\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section4\"\u003e \u003ch2\u003e2.2.5.2 Preparation of pH-dependent coating solution\u003c/h2\u003e \u003cp\u003eThe pH-dependent coating solutions were prepared by mixing the polymers Eudragit L100 and Eudragit S100 in various ratios as described in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The accurately weighed polymers were dissolved in a mixed solvent of acetone and IPA (1:1). The solvent was previously mixed with DBP (density: 1.05 gm/ml) at 2% w/w of the total dry weight of the polymers. The coating solution was homogenized by overnight mixing on a Remi magnetic stirrer with a magnetic bead before use [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cb\u003eComposition of pH-dependent coated pellets\u003c/b\u003e [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSr. No\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eFormulation\u003c/p\u003e \u003cp\u003eCode\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eEudragit L 100: Eudragit S 100\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eWeight of polymers\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003ePlasticizer\u003c/p\u003e \u003cp\u003e(2%w/w)\u003c/p\u003e \u003cp\u003e(gm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eTWG\u003c/p\u003e \u003cp\u003e(%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eEudragit\u003c/p\u003e \u003cp\u003eS 100\u003c/p\u003e \u003cp\u003e(gm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eEudragit\u003c/p\u003e \u003cp\u003eL 100\u003c/p\u003e \u003cp\u003e(gm)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH1\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH3\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH4\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH5\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH6\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e7.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH7\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e8.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH8\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e9.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH9\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH10\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e11.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH11\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e12.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH12\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e13.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH13\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2:3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e14.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH14\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2:3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e10\u003c/p\u003e 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align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2:3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e17.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH17\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e18.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH18\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e19.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH19\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH20\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e7.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e21.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH21\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3:2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e22.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH22\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3:2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e23.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH23\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3:2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e24.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH24\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3:2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e25.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH25\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e26.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH26\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e27.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH27\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e28.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eF \u003csub\u003epH28\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4:1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eDuring the stirring, the lids of the containers were frequently removed for a very short duration to expel the pressure generated by the accumulated solvent vapor inside, and the volume of the solutions was again maintained by adding the mixed solvents used.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section3\"\u003e \u003ch2\u003e2.2.6. Preparation of coated pellets\u003c/h2\u003e \u003cdiv id=\"Sec15\" class=\"Section4\"\u003e \u003ch2\u003e2.2.6.1 Preparation of Time dependent and pH dependent single coated pellets\u003c/h2\u003e \u003cp\u003eThe uncoated IBU-loaded pellets were used to first prepare the single-coated multi-particulate batches of various coating thicknesses measured in the form of theoretical percentage of weight gain (%-TWG). Different ratios of mixed HPC-HXF and EC 45-based time-dependent mixed polymeric coating solutions were applied over the uncoated pellets, with each solution again at various coating levels of 5%, 10%, 15%, and 20% TWG (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) to prepare the time-dependent trial batches. All coated pellets were dried for 1 hr at 40\u0026deg;C to remove the solvent residues [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. The ratio of HPC-HXF and EC 45 as well as their corresponding coating thickness was optimized by in vitro dissolution study, and the polymeric ratio of the best batch was then used to formulate the dual-coated trial batches.\u003c/p\u003e \u003cp\u003eSimilarly, pH-dependent single-coated multi-particulate batches were prepared by coating uncoated IBU-loaded pellets with pH-dependent mixed polymeric solutions of Eudragit L100: Eudragit S100 at different ratios and coating thicknesses as mentioned in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The coated multi-particulates were then dried for 1 hr at 40\u0026deg;C to remove the residual solvent. The ratio of Eudragit L100 and Eudragit S100 and their corresponding coating thickness was optimized by in vitro dissolution study, and the polymeric ratio of the best batch was then used to formulate the dual-coated trial batches [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section4\"\u003e \u003ch2\u003e2.2.6.2 Preparation of inner time and outer pH dependent dual coated pellets\u003c/h2\u003e \u003cp\u003eDouble coating was achieved by coating the uncoated IBU-loaded pellets initially with an optimized ratio of time-dependent mixed polymeric solution (inner coating layer) and, after drying them at 40\u0026deg;C for 1 hr, the next layer of pH-dependent coating (outer coating layer) was applied and again dried at 40\u0026deg;C for an hour. Both inner and outer layers were applied again at different coating thicknesses to prepare the dual-coated trial batches (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e) for further optimization by in vitro dissolution [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComposition of inner time dependent and outer pH dependent dual coated pellets.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eFormulation\u003c/p\u003e \u003cp\u003eCode.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eInner time-dependent coating\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003eOuter pH-dependent coating\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"1\" nameend=\"c7\" namest=\"c7\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eHPC-HXF:\u003c/p\u003e \u003cp\u003eEC 45\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e%-TWG\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eEudragit L100: Eudragit S100\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e%-TWG\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF\u003csub\u003eD1\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e5%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3:2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e5%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF\u003csub\u003eD2\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e5%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e10%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF\u003csub\u003eD3\u003c/sub\u003e\u003c/p\u003e \u003cp\u003eF\u003csub\u003eD4\u003c/sub\u003e\u003c/p\u003e \u003cp\u003eF\u003csub\u003eD5\u003c/sub\u003e\u003c/p\u003e \u003cp\u003eF\u003csub\u003eD6\u003c/sub\u003e\u003c/p\u003e \u003cp\u003eF\u003csub\u003eD7\u003c/sub\u003e\u003c/p\u003e \u003cp\u003eF\u003csub\u003eD8\u003c/sub\u003e\u003c/p\u003e \u003cp\u003eF\u003csub\u003eD9\u003c/sub\u003e\u003c/p\u003e \u003cp\u003eF\u003csub\u003eD10\u003c/sub\u003e\u003c/p\u003e \u003cp\u003eF\u003csub\u003eD11\u003c/sub\u003e\u003c/p\u003e \u003cp\u003eF\u003csub\u003eD12\u003c/sub\u003e\u003c/p\u003e \u003cp\u003eF\u003csub\u003eD13\u003c/sub\u003e\u003c/p\u003e \u003cp\u003eF\u003csub\u003eD14\u003c/sub\u003e\u003c/p\u003e \u003cp\u003eF\u003csub\u003eD15\u003c/sub\u003e\u003c/p\u003e \u003cp\u003eF\u003csub\u003eD16\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:4\u003c/p\u003e \u003cp\u003e1:4\u003c/p\u003e \u003cp\u003e1:4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e5%\u003c/p\u003e \u003cp\u003e5%\u003c/p\u003e \u003cp\u003e10%\u003c/p\u003e \u003cp\u003e10%\u003c/p\u003e \u003cp\u003e10%\u003c/p\u003e \u003cp\u003e10%\u003c/p\u003e \u003cp\u003e15%\u003c/p\u003e \u003cp\u003e15%\u003c/p\u003e \u003cp\u003e15%\u003c/p\u003e \u003cp\u003e15%\u003c/p\u003e \u003cp\u003e20%\u003c/p\u003e \u003cp\u003e20%\u003c/p\u003e \u003cp\u003e20%\u003c/p\u003e \u003cp\u003e20%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3:2\u003c/p\u003e \u003cp\u003e3:2\u003c/p\u003e \u003cp\u003e3:2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003e15%\u003c/p\u003e \u003cp\u003e20%\u003c/p\u003e \u003cp\u003e5%\u003c/p\u003e \u003cp\u003e10%\u003c/p\u003e \u003cp\u003e15%\u003c/p\u003e \u003cp\u003e20%\u003c/p\u003e \u003cp\u003e5%\u003c/p\u003e \u003cp\u003e10%\u003c/p\u003e \u003cp\u003e15%\u003c/p\u003e \u003cp\u003e20%\u003c/p\u003e \u003cp\u003e5%\u003c/p\u003e \u003cp\u003e10%\u003c/p\u003e \u003cp\u003e15%\u003c/p\u003e \u003cp\u003e20%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section3\"\u003e \u003ch2\u003e2.2.7 Percentage drug entrapment efficiency (%-DEE)\u003c/h2\u003e \u003cp\u003eSingle- or dual-coated multi-particulates containing 100 mg of IBU theoretically were crushed with the aid of a mortar and pestle and mixed with 100 ml of ethanol to form a slurry. The slurry was centrifuged for 15 min at 3000 rpm and filtered. The filtrate was diluted with distilled water and analyzed using a UV-visible spectrophotometer at a predetermined wavelength (221 nm) to determine the %-drug entrapment efficiencies. The following equation was used for the calculation of %-DEE [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDrug Entrapment Efficiency = (Practical absorbance / Standard absorbance) x100\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section3\"\u003e \u003ch2\u003e2.2.8 Percentage loose surface crystals (%-LSC)\u003c/h2\u003e \u003cp\u003eIn separate 100 ml volumetric flasks, coated pellets from each trial batch containing theoretically equivalent to 100 mg of IBU were taken, and the volume was made up to 100 ml with SCF (pH 7.4 phosphate buffer). The flasks were shaken vigorously for 5 minutes to allow any crystalline loose drug adhered to the coated surface to leach out from the suspended multi-particulates into the SCF. The SCF medium of each corresponding trial batch was further diluted and evaluated at 221 nm in a UV-visible spectrophotometer. The absorbance data for each trial batch were used to determine the percentage of loose surface crystals of IBU present on the surface of the coated pellets [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section3\"\u003e \u003ch2\u003e2.2.9 Micromeritic Characterization of coated pellets\u003c/h2\u003e \u003cp\u003eStandard sieve analysis was used to determine the particle size and particle size distribution (PSD) of each batch of coated pellets as per the published protocol of Shah et al. (2024), and the PSD data has been presented graphically [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. Percentage compressibility and relative flowability of the coated multi-particulates were obtained by calculating the Carr\u0026rsquo;s compressibility index and the Hausner ratio from the bulk densities and tapped densities of coated pellets from each trial batch. The data was tabulated, analysed, and compared[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. The following formularies were used.\u003c/p\u003e \u003cp\u003eCarr\u0026rsquo;s Compressibility Index (%) = (Tapped Density -Bulk Density)/Tapped Density*100\u003c/p\u003e \u003cp\u003eHausner Ratio =Tapped Density/Bulk Density\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section3\"\u003e \u003ch2\u003e2.2.10 In vitro drug release, drug release kinetic study and mean dissolution time\u003c/h2\u003e \u003cp\u003eThe \u003cem\u003ein vitro\u003c/em\u003e drug release studies of trial batches were carried out using a USP Type 1 \u003cem\u003ein vitro\u003c/em\u003e drug dissolution testing apparatus at 100 rpm, maintained at a temperature of 37.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5\u0026deg;C. Multi-particulates containing an equivalent of a 400 mg dose of IBU were taken from each trial batch based upon the %-DEE and were studied first in 900 ml of SGF (pH 1.2) for the initial 2 hours, then in 900 ml of SSIF (pH 6.8) for another 3 hours, and finally in SCF (pH 7.4) for an additional 7 hours. As the main object of the current study is to rely on GI transit time and pH variations to trigger the colonic release of the drug beyond ileocecal segment irrespective of colonic microflora diversity and enzymes, neither human faecal nor animal faecal or caecal content nor pro-biotic bacterial cultures in FTM nor any colonic bacterial enzyme such as pectinase were added. Later the best single and dual coated batches were reassessed \u003cem\u003ein vitro\u003c/em\u003e using probiotic biomix-I previously incubated in FTM and then added in the SCF to simulate colonic microbial conditions \u003cem\u003ein vitro\u003c/em\u003e as per the biorelevant animal sparing published protocols of Singh S. et al. (2015) and Yadav A. et al. (2017) [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. The data was later compared and analysed. Throughout the \u003cem\u003ein vitro\u003c/em\u003e dissolution process, samples of 5 ml were withdrawn at predetermined time intervals using a sample ejector and replaced with 5 ml of fresh corresponding buffer to maintain the sink condition. The concentration of IBU in each sample was determined using the UV-visible spectrophotometer. The cumulative percentage of drug release data and the corresponding time intervals were used to understand the mechanism of drug release and drug release kinetics from the coated multi-particulate pellets. These data were plotted in various mathematical models like zero-order, first-order, Higuchi, and Korsmeyer-Peppas models to obtain the best fit [\u003cspan additionalcitationids=\"CR36 CR37\" citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTo determine the efficiency of the polymeric coatings in retarding the release of IBU in the simulated upper gastrointestinal (GI) conditions and to assess the characteristics of the rate of drug release through these polymeric coatings on the coated pellets, MDT (mean dissolution time) of all trial batches was calculated using the equation mentioned below [\u003cspan additionalcitationids=\"CR40\" citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eMDT = (n/n\u0026thinsp;+\u0026thinsp;1). K\u003csup\u003e\u0026minus;\u0026thinsp;1/n\u003c/sup\u003e [\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section3\"\u003e \u003ch2\u003e2.2.11 Surface morphology by Scanning electron microscopy (SEM)\u003c/h2\u003e \u003cp\u003eThe surface topography of coated pellets was studied using SEM. Samples from uncoated pellets and coated pellets showing the best colon targeting efficiency prior to and post in vitro dissolution were taken to study the effects of polymeric coatings over uncoated surfaces and the effects of simulated GI fluids on the polymeric coatings. The samples were attached to a stub with a double-sided tape coated with a thin layer of gold using a sputter coater. The coated samples were then observed under the scanning electron microscope (Zeiss GeminiSEM 300, Germany) at various magnifications, and images were taken for further analysis [\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec22\" class=\"Section3\"\u003e \u003ch2\u003e2.2.12 Statistical analysis\u003c/h2\u003e \u003cp\u003eOne-way and Two-way ANOVA were used to statistically analyse and compare the \u003cem\u003ein vitro\u003c/em\u003e drug release from the various formulation trial batches utilising the GraphPad Prism statistical software. A probability level value of less than 0.05 (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05) was regarded as statistically significant [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e]. Based on the data obtained from the statistical analysis, the best double coated trial batch was selected and the colon targeting efficiency of the statistically significant batch was further evaluated in \u003cem\u003ein vivo\u003c/em\u003e conditions using New Zealand white rabbits.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec23\" class=\"Section3\"\u003e \u003ch2\u003e2.2.13 In vivo animal study conditions\u003c/h2\u003e \u003cp\u003e The animal study protocol (IAEC/KSOP/2023-24/16, dated 18/11/2023) was duly approved by the Institutional Animal Ethical Committee of KIET School of Pharmacy, Ghaziabad, India, which is registered with CCSEA (Reg. no. 1099/PO/Re/S/07/CPCSEA). All in vivo animal studies in living animals must adhere to the guidelines laid down by the CCSEA (Committee for Control and Supervision of Experiments on Animals) in India and need to follow the OECD (Organization for Economic Co-operation and Development) test guidelines. These guidelines, rules, and regulations are at par with the international standards like EU Directive 2010/63/EU, the National Research Council's Guide for the Care and Use of Laboratory Animals, the ARRIVE guidelines (National Centre for the Replacement, Refinement, and Reduction of Animals in Research), and the U.K. Animals (Scientific Procedures) Act, 1986 [\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e]. Several previously published protocols involving in vivo evaluation of CTDDSs have highlighted the benefits of using New Zealand white rabbit-based models, including adequate belly size for imaging techniques, ease of administration of multi-particulates via the oral route, and the possibility for the collection of sufficient amounts of blood for plasma analysis. Thus, New Zealand white rabbits were used for the in vivo X-ray roentgenography study and in vivo animal plasma analysis study [\u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e, \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec24\" class=\"Section3\"\u003e \u003ch2\u003e2.2.13.1 In vivo X-ray Roentgenography study\u003c/h2\u003e \u003cp\u003eTwelve well-acclimatized white New Zealand rabbits of either sex (average weight 3\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5 kg) were taken and divided into two groups of six animals each as trial and control groups. The animals were fasted overnight prior to study and allowed only water. The coated multi-particulate batch showing the best colon targeting efficiency as per the statistical analysis was again freshly prepared, but the entrapped IBU inside was replaced with the X-ray contrasting agent barium sulphate (BaSO\u003csub\u003e4\u003c/sub\u003e). The non-toxic radiopaque BaSO\u003csub\u003e4\u003c/sub\u003e is generally used to obtain the X-ray images of the GI tract, as it is generally considered safe and does not get absorbed through the GIT [\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e]. Coated pellets suspended in 10 ml of distilled water were orally fed to the animals of the trial group, whereas the other group was kept as the control. A high-frequency X-ray machine (GME 500), set at 4 MAS and 50 KV, was used to capture the X-ray roentgenography images of coated pellets transversing through the GIT at predetermined time intervals, and these abdominal scans were later studied to determine the efficiency of the colon-targeted coated multi-particulates [\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e, \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec25\" class=\"Section3\"\u003e \u003ch2\u003e2.2.13.2 In vivo plasma analysis\u003c/h2\u003e \u003cp\u003ePreviously established methods by YILIMAZ B. et al. (2009) and Rachmawati, Heni, et al. (2012) were adopted to perform the \u003cem\u003ein vivo\u003c/em\u003e plasma analysis with minor modifications. Properly acclimatized, twelve white albino New Zealand rabbits (of either sex) were taken and divided into two groups of six animals each. The animals were 4\u0026ndash;6 months of age with 2.5 to 3.5 kg of bodyweight. One group was kept as a control while the other group was used for the trials. The animals in both groups were fasted for 12 hr overnight prior to the study with access to only water. The freshly prepared, best-performing, dual-coated formulation batch and uncoated pellets, both carrying an equivalent animal dose of 20 mg/kg of IBU [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e], were administered via the oral route into the rabbits in the trial group using a polyethylene cannula of 2 mm diameter along with 1 ml of distilled water. The rabbits in the control group were given water only. No food was allowed during the study, but the animals were allowed to freely move inside the cage with access to plenty of drinking water. The concentrations of IBU in plasma were ascertained in the Agilent 1120 Compact reversed-phase HPLC (high-performance chromatography) with a C18 column (HC-C18(2) Column, 4.6 x 150 mm, 5 \u0026micro;m, 400 bar). At previously determined specific time points, i.e., just before the oral administration (0 hr) and at 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 15, and 18 hr post oral administration, about 1 ml of blood samples were collected from the marginal ear veins of the rabbits in heparinized tubes, vortexed immediately for 1 min, and centrifuged at 10,000xg for 10 min. The separated plasma samples were transferred inside the microcentrifuge tubes. From these 0.2 mL plasma samples, aliquots were taken into separate glass tubes with Teflon-lined caps. 0.6 mL of acetonitrile was added into each of the aliquots and vortexed for 5 min, followed by centrifugation at 10,000xg for 5 min. The obtained organic supernatant layers were again transferred into another 5 ml tube and dried by evaporation under the stream of nitrogen (N\u003csub\u003e2\u003c/sub\u003e) gas at 40\u0026ordm;C. The dried residues were redissolved in 0.2 mL of mobile phase, vortexed for 1 min, and then centrifuged for 3 min at 10,000 xg. Aliquots of 0.02 ml from each sample were injected into the HPLC system to determine the IBU concentration in the rabbit plasma at various time intervals. The mobile phase used was composed of 20 mM phosphate buffer (pH 7) and acetonitrile (60:40, v/v) with 0.1% trifluoroacetic acid (TFA). The filtered mobile phase was pumped at a 1 ml/min flow rate. The eluent was monitored using a UV detector at 221 nm. Naproxen was used as an internal standard (IS). After a 15-day washing-out period, in vivo plasma analysis for the uncoated IBU pellets was performed similarly and compared with the previous result of the dual-coated pellets [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e]. The mean plasma concentrations of IBU in rabbits following the oral administration of best performing batch (F\u003csub\u003eD16\u003c/sub\u003e) and the uncoated drug loaded pellets were plotted alongside their corresponding time points and analysed.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"3. Results and Discussions","content":"\u003cp\u003e\u003cem\u003e3.1 UV-visible spectrophotometry study and standard calibration curve\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe \u0026lambda;\u003csub\u003emax\u0026nbsp;\u003c/sub\u003eof IBU was obtained at 221 nm (Figure 1a). All standard curves plotted in various simulated GI fluids as mentioned above were found to be linear and followed Beer-Lambert\u0026rsquo;s law at the concentration range from 1 to 19 \u0026mu;g/ml (Figure 1b\u0026ndash;1e) [52,53].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3.2. FT-IR Study\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe FT-IR spectra of pure IBU, individual polymers, and drug polymer physical mixture (representing the best dual-coated batch) are displayed in Figure 1f to Figure 1k, respectively. The pure IBU showed its characteristic peaks at 3778.55 cm⁻\u0026sup1; due to single bond O-H stretch, at 2630.91 cm⁻\u0026sup1; for single bond C-H stretch, at 2943.37 cm⁻\u0026sup1; for CH bending, and at 1226.73 cm⁻\u0026sup1; and 2872 cm⁻\u0026sup1; due to C-C and C-H groups. The iso-propionic acid group of IBU also had displayed the characteristic infrared band at 1718.58 cm⁻\u0026sup1; of carbonyl stretching [54]. The FT-IR spectra of the drug-polymer physical mixture also showed similar characteristic peaks of IBU in its FTIR spectra without any major changes, and the remaining peaks due to the polymers used were also at par with the characteristic FT-IR spectra of pure polymers [54].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3.3 DSC study\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eDSC thermographs of the drug IBU and the polymers Eudragit L100, Eudragit S100, HPC-HXF, and EC45 (Figure 1l to 1q) showed endothermic peaks at 81.376\u0026deg;C, 92.887\u0026deg;C, 90.549\u0026deg;C, 132.716\u0026deg;C, and 139.199\u0026deg;C, respectively. The IBU present in the drug-physical mixture showed a minor shift in its endothermic peak at 79.607\u0026deg;C [55].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3.4 Percentage drug entrapment efficiency\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe best single-coated time-dependent batch (FTm16) had a %-DEE of 95.06\u0026plusmn;0.69%. Similarly, the best pH-based single-coated formulation batch (FpH24) had shown a drug entrapment efficiency of 96.96\u0026plusmn;0.73%. Among all double-coated batches, the %-DEE had varied between 85.93\u0026plusmn;0.52% (FD16) and 96.77\u0026plusmn;0.67% (Table 4). \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3.5 Loose surface crystal (LSC) study\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe best time-dependent (F\u003csub\u003eTm16\u003c/sub\u003e) and pH-dependent (F\u003csub\u003epH24\u003c/sub\u003e) batches had shown %-LSC of 1.154 \u0026plusmn; 0.11% and 1.162 \u0026plusmn; 0.09%, respectively. The best double-coated batch, F\u003csub\u003eD16\u003c/sub\u003e, showed %-LCS of 0.746 \u0026plusmn; 0.08%, and the %-LSC varied from 0.645 \u0026plusmn; 0.05% to 1.123 \u0026plusmn; 0.13% across all double-coated batches (Table 4). \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 4. Drug entrapment efficiency, loose surface crystal, micrometric properties of coated multi-particulates (n=3).\u003c/strong\u003e\u003c/p\u003e\n\u003cdiv align=\"\"\u003e\u003cimg src=\"https://myfiles.space/user_files/58895_8739fc6c57c1c19a/58895_custom_files/img1771838241.png\" width=\"953\" height=\"611\"\u003e\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3.6\u0026nbsp;\u003c/em\u003e\u003cem\u003eMicromeritic properties and Particle Size and Size Distribution\u003c/em\u003e\u003cem\u003e\u0026nbsp;(PSD)\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eMost of the coated multi-particulates fell within the 1000 to 1300 \u0026micro;m particle size range, with PSD found to be varying between 69.53\u0026plusmn;0.16% and 80.58\u0026plusmn;0.09% in the #12 mesh size range across all dual-coated pellet batches (Figure 2). The Hausner ratio and the Carr\u0026rsquo;s compressibility index were determined for all coated multi-particulate batches using the respective tapped and bulk densities and are shown in Table 4. The best dual-coated batch showed an excellent Carr\u0026rsquo;s index value of 9.074\u0026plusmn;0.090 and a Hausner ratio of 1.100\u0026plusmn;0.02.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3.7. In vitro drug release study\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eUpon analyzing the \u003cem\u003ein vitro\u0026nbsp;\u003c/em\u003edrug release from the single coated multi-particulate batches first had yielded the batches F\u003csub\u003epH24\u003c/sub\u003e (pH-dependent) and F\u003csub\u003eTm16\u003c/sub\u003e (time-dependent) to be with the best colon targeting potential in their respective classes. The batches F\u003csub\u003eTm16\u003c/sub\u003e and F \u003csub\u003epH24\u0026nbsp;\u003c/sub\u003ehad \u003cem\u003ein vitro\u003c/em\u003e cumulative percentages of IBU release of 1.794\u0026plusmn;0.037% vs 2.727\u0026plusmn;0.052% in SGF, 12.873\u0026plusmn;2.157% vs 18.697\u0026plusmn;2.356% in SSIF and 85.773\u0026plusmn;6.654% vs 95.335\u0026plusmn;3.544% in SCF with MDTs of 17.4064 hr. vs 15.9866 hr. respectively. In both the time and pH-dependent categories, the single coated multi-particulates with 5%-TWG of coating thicknesses were unable to restrict the early release of IBU in simulated upper GI conditions \u003cem\u003ein vitro\u003c/em\u003e and hence their data were not reported in this study. Thus, the polymeric ratio inside these batches were considered to prepare the dual coated multi-particulate batches. The best dual coated batch (F\u003csub\u003eD16\u003c/sub\u003e) had shown even lesser amount of IBU release i.e., up to 1.563\u0026plusmn;0.038% in SGF, up to 6.163\u0026plusmn;0.227% in SSIF and up to 96.637\u0026plusmn;4.361% in SCF. The best batch was able to localize almost 90% of the drug under \u003cem\u003ein vitro\u003c/em\u003e simulated colonic conditions using GI pH and transit time.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe best pH-dependent, time-dependent and dual coated multi-particulate batches were again sent for \u003cem\u003ein vitro\u003c/em\u003e dissolution studies in the presence of colonic bacterial enzymatic environment simulated \u003cem\u003ein vitro\u0026nbsp;\u003c/em\u003eby the addition of biomix-I culture in FTM. The cumulative amount of IBU release in the simulated \u003cem\u003ein vitro\u003c/em\u003e upper GI conditions was found to be lowest in the best dual coated batch. The use of biomix-I culture to artificially simulate the colonic microflora, and its enzymatic conditions is a biorelevant and animal sparing alternative that have already been established by Singh S. et al. 2015 [33]. Thus, the published protocol of Singh S. et al. 2015 and Yadav et al. 2017 were used to simulate the colonic bacterial enzymatic environment \u003cem\u003ein vitro\u0026nbsp;\u003c/em\u003eby adding FTM containing biomix-I culture in the SCF [34]. The cumulative percentage of IBU release from the best double-coated batch (F\u003csub\u003eD16\u003c/sub\u003e) in presence of simulated colonic microflora was found to be up to\u0026nbsp;1.671\u0026plusmn;0.042%\u0026nbsp;in SGF (pH 1.2), up to 5.786\u0026plusmn;0.231% in SSIF (pH 6.8) and up to 97.108\u0026plusmn;4.47% in SCF (pH 7.4) with colonic microflora. Thus, the best dual coated\u0026nbsp;F\u003csub\u003eD16\u003c/sub\u003e batch was able to localize about 92% of IBU in presence of colonic microflora in SCF vs 90% of IBU in absence of colonic microflora in SCF depending solely on variations in GI pH and GI transit time (Figure 3 d). Thus, the batch F\u003csub\u003eD16\u003c/sub\u003e had the lowest amount of IBU release in both SGF and SSIF amongst all double-coated batches and had been taken forward for the in vivo X-ray roentgenography and plasma analysis studies in New Zealand white rabbits for the further verification of its colon targeting efficiency under actual \u003cem\u003ein vivo\u003c/em\u003e conditions. The cumulative percentage of IBU release from all trial batches is shown in Table 5 as well as graphically represented in Figure 3.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3.8 Drug release kinetics and the MDT (mean dissolution time)\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAll under trial single and double coated formulation batches including the best dual coated batch F\u003csub\u003eD16\u0026nbsp;\u003c/sub\u003ehad followed zero order drug release model with Korsmeyer-Peppas super case-II transports mechanism (n\u0026gt;1). The highest mean dissolution time of 29.319 hr was observed in case of the best dual coated batch F\u003csub\u003eD16\u003c/sub\u003e. The drug release kinetics data including MDT for all trial batches has been reported in Table 5.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3.9 Statistical analysis\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe difference in \u003cem\u003ein vitro\u0026nbsp;\u003c/em\u003eIBU release from the single coated F\u003csub\u003eTM16\u003c/sub\u003e, F \u003csub\u003epH24\u003c/sub\u003e, and dual coated F\u003csub\u003eD16\u003c/sub\u003e batches in SGF was found to statistically non-significant (\u003cem\u003ep\u003c/em\u003e = 0.1605) using One-way Anova. Two-way Anova also yielded same non-significant \u003cem\u003ep\u003c/em\u003e values in SGF (Row factor \u003cem\u003ep\u003c/em\u003e=0.1228, column factor \u003cem\u003ep\u003c/em\u003e=0.0663). \u0026nbsp; But, one-way Anova has yielded a significant difference between the cumulative percentages in \u003cem\u003ein vitro\u0026nbsp;\u003c/em\u003eIBU releases between the best dual coated F\u003csub\u003eD16\u0026nbsp;\u003c/sub\u003ebatch and the selected single coated (F\u003csub\u003eTM16\u003c/sub\u003e and F \u003csub\u003epH24\u003c/sub\u003e) batches in SSIF (\u003cem\u003ep\u003c/em\u003e = 0.0100) at its 5\u003csup\u003eth\u003c/sup\u003e hr end point. In Two-way Anova, the differences between them were also significant (Row factor \u003cem\u003ep\u003c/em\u003e=0.0346, column factor \u003cem\u003ep\u003c/em\u003e=0.0021) in SSIF. Two-way Anova test of amount of IBU release from the above-mentioned batches in SCF had shown a significant difference (Row factor \u003cem\u003ep\u003c/em\u003e\u0026lt;0.0001, column factor \u003cem\u003ep\u003c/em\u003e=0.0447) in favour of the dual coated formulation batch.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3.10 The surface topography of coated\u0026nbsp;\u003c/em\u003e\u003cem\u003ePellets\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eCaptured surface images of the pellets by SEM at various stages of their preparation and evaluation, with each having unique surface topography has been reported in Figure 1r to Figure 1u. SEM surface images of uncoated pellets just after drug loading (1r), up on the application of inner time-dependent coating layer (1s), after the outer pH-dependent coating layer (1t) before subjecting them to the \u003cem\u003ein-vitro\u003c/em\u003e dissolution studies and after going through the \u003cem\u003ein-vitro\u003c/em\u003e dissolution studies (1u) had provided a detailed outlook on their surface topographies.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3.12.1. In vivo\u0026nbsp;\u003c/em\u003e\u003cem\u003eX-Ray Roentgenography\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAt specific predetermined time intervals of 1.5 hr., 3.5 hr., 4 hr., and 7 hr., X-ray Roentgenographic images were captured for the orally fed statistically significant batch F\u003csub\u003eD16\u003c/sub\u003e to monitor the GI transit behavior of the double coated BaSO\u003csub\u003e4\u003c/sub\u003e loaded pellets through the stomach, small intestine, and colon \u003cem\u003ein vivo\u003c/em\u003e. Despite containing a small amount of X-ray opaque material BaSO\u003csub\u003e4\u003c/sub\u003e, the coated pellets became visible in the X-ray images (Figure 4a to 4d). \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 5. Comparative data of percentage drug release, drug-release kinetics and mean dissolution time of trial batches (n=6).\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"1064\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFormulation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 119px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSGF\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 111px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSSIF\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSCF\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 128px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eZero Order Model\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 128px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFirst Order Model\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 128px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eHiguchi Model\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" style=\"width: 192px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eKorsmeyer- Peppas Model\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMDT\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCode\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 119px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e(2 hr)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 111px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e(5 hr)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e(12 hr)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u003cstrong\u003er2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ek\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u003cstrong\u003er2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ek\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 58px;\"\u003e\n \u003cp\u003e\u003cstrong\u003er2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 70px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ek\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 55px;\"\u003e\n \u003cp\u003e\u003cstrong\u003er2\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 73px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ek\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 64px;\"\u003e\n \u003cp\u003e\u003cstrong\u003en\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e(hr.)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003eF\u003csub\u003eTm16\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 119px;\"\u003e\n \u003cp\u003e1.794\u0026plusmn;0.037\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 111px;\"\u003e\n \u003cp\u003e12.873\u0026plusmn;2.157\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e94.563\u0026plusmn;6.654\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.889\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e8.933\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.758\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.173\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 58px;\"\u003e\n \u003cp\u003e0.770\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 70px;\"\u003e\n \u003cp\u003e33.292\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 55px;\"\u003e\n \u003cp\u003e0.9852\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e0.007260\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.05292\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e17.4064\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003eF\u003csub\u003epH24\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 119px;\"\u003e\n \u003cp\u003e2.727\u0026plusmn;0.052\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 111px;\"\u003e\n \u003cp\u003e18.697\u0026plusmn;2.356\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e98.475\u0026plusmn;3.544\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.948\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e10.612\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.795\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.261\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 58px;\"\u003e\n \u003cp\u003e0.862\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 70px;\"\u003e\n \u003cp\u003e40.538\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 55px;\"\u003e\n \u003cp\u003e0.8431\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e0.007905\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.24269\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e15.9866\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003eF\u003csub\u003eD1\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 119px;\"\u003e\n \u003cp\u003e2.065\u0026plusmn;0.012\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 111px;\"\u003e\n \u003cp\u003e13.161\u0026plusmn;0.102\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e99.362\u0026plusmn;4.112\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.870\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e8.833\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.529\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.104\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 58px;\"\u003e\n \u003cp\u003e0.751\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 70px;\"\u003e\n \u003cp\u003e32.088\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 55px;\"\u003e\n \u003cp\u003e0.9910\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e0.00730\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.01760\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e17.6568\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003eF\u003csub\u003eD2\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 119px;\"\u003e\n \u003cp\u003e1.796\u0026plusmn;0.021\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 111px;\"\u003e\n \u003cp\u003e12.569\u0026plusmn;0.116\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e99.232\u0026plusmn;3.112\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.881\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e9.456\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.621\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.103\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 58px;\"\u003e\n \u003cp\u003e0.762\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 70px;\"\u003e\n \u003cp\u003e34.377\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 55px;\"\u003e\n \u003cp\u003e0.9852\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e0.00553\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.02126\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e18.7563\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003eF\u003csub\u003eD3\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 119px;\"\u003e\n \u003cp\u003e1.447\u0026plusmn;0.051\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 111px;\"\u003e\n \u003cp\u003e11.681\u0026plusmn;0.654\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e98.319\u0026plusmn;4.117\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.855\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e8.893\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.638\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.086\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 58px;\"\u003e\n \u003cp\u003e0.730\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 70px;\"\u003e\n \u003cp\u003e32.124\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 55px;\"\u003e\n \u003cp\u003e0.9900\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e0.00380\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.02907\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e20.4418\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003eF\u003csub\u003eD4\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 119px;\"\u003e\n \u003cp\u003e1.016\u0026plusmn;0.037\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 111px;\"\u003e\n \u003cp\u003e10.156\u0026plusmn;0.741\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e97.161\u0026plusmn;4.223\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.809\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e7.981\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.585\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.073\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 58px;\"\u003e\n \u003cp\u003e0.678\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 70px;\"\u003e\n \u003cp\u003e28.553\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 55px;\"\u003e\n \u003cp\u003e0.9903\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e0.00278\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.02994\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e22.1575\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003eF\u003csub\u003eD5\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 119px;\"\u003e\n \u003cp\u003e1.824\u0026plusmn;0.025\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 111px;\"\u003e\n \u003cp\u003e12.125\u0026plusmn;0.417\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e99.361\u0026plusmn;3.745\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.878\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e9.273\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.612\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 58px;\"\u003e\n \u003cp\u003e0.753\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 70px;\"\u003e\n \u003cp\u003e33.586\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 55px;\"\u003e\n \u003cp\u003e0.9917\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e0.00387\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.02711\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e20.3786\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003eF\u003csub\u003eD6\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 119px;\"\u003e\n \u003cp\u003e1.607\u0026plusmn;0.039\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 111px;\"\u003e\n \u003cp\u003e11.174\u0026plusmn;0.645\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e98.150\u0026plusmn;4.325\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.866\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e8.850\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.626\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.086\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 58px;\"\u003e\n \u003cp\u003e0.739\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 70px;\"\u003e\n \u003cp\u003e31.961\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 55px;\"\u003e\n \u003cp\u003e0.9578\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e0.002298\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.03674\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e23.2447\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003eF\u003csub\u003eD7\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 119px;\"\u003e\n \u003cp\u003e1.604\u0026plusmn;0.048\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 111px;\"\u003e\n \u003cp\u003e10.355\u0026plusmn;0.517\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e97.676\u0026plusmn;4.256\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.855\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e8.390\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.611\u003c/p\u003e\n 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55px;\"\u003e\n \u003cp\u003e0.9808\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e0.001409\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.04157\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e26.7265\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003eF\u003csub\u003eD9\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 119px;\"\u003e\n \u003cp\u003e2.133\u0026plusmn;0.135\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 111px;\"\u003e\n \u003cp\u003e12.714\u0026plusmn;0.524\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e98.747\u0026plusmn;4.521\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.859\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e8.775\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.602\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.089\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 58px;\"\u003e\n \u003cp\u003e0.733\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 70px;\"\u003e\n \u003cp\u003e31.687\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 55px;\"\u003e\n \u003cp\u003e0.9922\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e0.003500\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.03016\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e20.8595\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n 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103px;\"\u003e\n \u003cp\u003e96.135\u0026plusmn;4.117\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.808\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e7.741\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.560\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.069\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 58px;\"\u003e\n \u003cp\u003e0.675\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 70px;\"\u003e\n \u003cp\u003e27.658\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 55px;\"\u003e\n \u003cp\u003e\u003cem\u003e0.9911\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e0.00128\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.04188\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e27.4927\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003eF\u003csub\u003eD12\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 119px;\"\u003e\n \u003cp\u003e1.567\u0026plusmn;0.047\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 111px;\"\u003e\n \u003cp\u003e8.049\u0026plusmn;0.423\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e95.828\u0026plusmn;3.776\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.779\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e7.381\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n 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119px;\"\u003e\n \u003cp\u003e1.990\u0026plusmn;0.042\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 111px;\"\u003e\n \u003cp\u003e11.262\u0026plusmn;0.515\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e99.565\u0026plusmn;4.256\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.866\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e8.777\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.649\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.083\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 58px;\"\u003e\n \u003cp\u003e0.740\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 70px;\"\u003e\n \u003cp\u003e31.727\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 55px;\"\u003e\n \u003cp\u003e0.9915\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e0.003337\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.03236\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e21.0867\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003eF\u003csub\u003eD14\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 119px;\"\u003e\n \u003cp\u003e1.811\u0026plusmn;0.045\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 111px;\"\u003e\n \u003cp\u003e10.340\u0026plusmn;0.603\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e98.739\u0026plusmn;4.223\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.849\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e8.285\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.658\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.072\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 58px;\"\u003e\n \u003cp\u003e0.721\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 70px;\"\u003e\n \u003cp\u003e29.840\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 55px;\"\u003e\n \u003cp\u003e0.9938\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e0.001546\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.04151\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e25.9838\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003eF\u003csub\u003eD15\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 119px;\"\u003e\n \u003cp\u003e1.930\u0026plusmn;0.044\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 111px;\"\u003e\n \u003cp\u003e9.734\u0026plusmn;0.417\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e97.512\u0026plusmn;4.569\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.835\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e7.749\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.645\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.063\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 58px;\"\u003e\n \u003cp\u003e0.705\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 70px;\"\u003e\n \u003cp\u003e27.823\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 55px;\"\u003e\n \u003cp\u003e0.9896\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e0.00125\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.04456\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e27.6739\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 93px;\"\u003e\n \u003cp\u003eF\u003csub\u003eD16\u003c/sub\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 119px;\"\u003e\n \u003cp\u003e1.563\u0026plusmn;0.038\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 111px;\"\u003e\n \u003cp\u003e6.163\u0026plusmn;0.227\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 103px;\"\u003e\n \u003cp\u003e96.637\u0026plusmn;4.361\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.763\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e7.017\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.593\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 64px;\"\u003e\n \u003cp\u003e0.055\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 58px;\"\u003e\n \u003cp\u003e0.627\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 70px;\"\u003e\n \u003cp\u003e24.879\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 55px;\"\u003e\n \u003cp\u003e0.9775\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003e0.00104\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 64px;\"\u003e\n \u003cp\u003e2.04485\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 62px;\"\u003e\n \u003cp\u003e29.3190\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cem\u003e3.12.2.\u0026nbsp;\u003c/em\u003e\u003cem\u003eIn vivo Plasma analysis\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eFigure 4e. represents the \u003cem\u003ein vivo\u0026nbsp;\u003c/em\u003emean plasma concentration of IBU after oral administration of uncoated IBU-loaded pellets and dual-coated multi-particulates of the best-performing batch F\u003csub\u003eD16\u003c/sub\u003e as per \u003cem\u003ein vitro\u003c/em\u003e dissolution studies. According to the obtained data, a notable difference in C\u003cem\u003e\u003csub\u003emax\u003c/sub\u003e\u003c/em\u003e and T\u003cem\u003e\u003csub\u003emax\u003c/sub\u003e\u003c/em\u003e was observed between the uncoated and the double-coated formulation batches. At 4\u003csup\u003eth\u003c/sup\u003e and 5\u003csup\u003eth\u003c/sup\u003e hr, the mean plasma concentrations of IBU were 0.31\u0026plusmn;0.02 \u0026mu;g/ml and 0.38\u0026plusmn;0.02 \u0026mu;g/ml when, according to the X-ray roentgenography study, the coated multi-particles were inside the small intestine. Whereas at 6\u003csup\u003eth\u003c/sup\u003e, 7\u003csup\u003eth\u003c/sup\u003e, and 8\u003csup\u003eth\u003c/sup\u003e hr the mean plasma concentrations of IBU were 0.48\u0026plusmn;0.02 \u0026mu;g/ml, 0.54\u0026plusmn;0.03 \u0026mu;g/ml, and 0.66\u0026plusmn;0.06 \u0026mu;g/ml, when the coated multi-particles would have been inside the cecum. At 9\u003csup\u003eth\u003c/sup\u003e hr onwards a sudden increase in the mean plasma concentration of IBU was observed and the maximum mean plasma concentration (C\u003csub\u003emax\u003c/sub\u003e) was found to be at 5.97\u0026plusmn;0.41 \u0026mu;g/ml for the best dual-coated batch (F\u003csub\u003eD16\u003c/sub\u003e) but was retarded till the 12\u003csup\u003eth\u003c/sup\u003e hr (Tmax) of the study when the coated pellets would have been deep inside the colon. On the contrary, the uncoated IBU-loaded pellets had demonstrated the maximum mean plasma IBU concentration of 6.07\u0026plusmn;0.36 \u0026mu;g/ml, which was reached early at 2\u003csup\u003end\u003c/sup\u003e hr (Tmax) of the study. The mean plasma concentrations of IBU gradually kept getting reduced thereafter at the end of the 18\u003csup\u003eth\u003c/sup\u003e hr for both the batches.\u003c/p\u003e"},{"header":"4. Discussions","content":"\u003cp\u003eThe λ\u003csub\u003emax\u003c/sub\u003e of ibuprofen was obtained at 221 nm. All standard curves plotted were found to be linear and followed Beer- Lambert\u0026rsquo;s at a concentration range from 1\u0026ndash;19 \u0026micro;g/ml [\u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e]. Several characteristic peaks in the IBU's FT-IR spectra are representative of the compound's distinctive pharmacological activity and can interact with the polymers being used. The presence of similar FT-IR peaks in the drug-polymer physical mixture without any major shifts and absence of any new peaks indicates drug-polymer compatibility. The minor shift observed in the endothermic DSC thermograph peaks of IBU and the polymers in the drug-polymer physical mixture compared to their individual DSC thermographs can be due to exceedingly weak physical interactions between the polymers and drug, a phenomenon that is common in polymers-coated formulations. Lack of new peaks and significant shifts reflects drug-polymer compatibility [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Thus, the drug-polymer compatibility can be ensured from these results. PVP K30D in 5% w/v solution had sufficient activity as binder to adhere the powdered drug over the inert sugar seeds with over 85 %-DEE, ver negligible %-LSC (\u0026lt;\u0026thinsp;1.5%), and fair to excellent flow properties and compressibility as per Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. The concentration of the binder had not impacted the \u003cem\u003ein vitro\u003c/em\u003e and \u003cem\u003ein vivo\u003c/em\u003e release of IBU while minimizing the %-LSC which would have caused irregular drug release. These results collaborated with the previous studies using powder layering technology [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e2\u003c/span\u003e also indicates majority of the prepared coated pellets had lied within a uniform size range. These factors might be helpful in either incorporating the prepared coated pellets inside capsules or compressing them into tablets. Both the prepared coating solutions were found to be sprayable and were not too viscous (200\u0026ndash;450 cp). An increase in EC 45 had slightly increased the viscosity of these solutions. As per the \u003cem\u003ein vitro\u003c/em\u003e drug release data obtained, the best dual coated batch was able to minimize the release of IBU in simulated upper GI conditions while released maximum amount of the drug at pH 7.4 and after 5 hr in SCF in the absence of colonic microflora. The presence of colonic microflora had not impacted the release of IBU form the coated pellets as these bacteria only secretes enzymes to degrade complex polysaccharides and not the time- and pH-dependent polymers used in the current study. Thus, the release of the drug from the dual coated pellets were controlled by the pH and time. The SEM images had showed rough surface of uncoated pellets turned smoother with the application of successive coating layers (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e1\u003c/span\u003er-\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e1\u003c/span\u003et). These images also indicate the swelling, erosion and degradation of polymeric coating layers post \u003cem\u003ein vitro\u003c/em\u003e dissolution (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e1\u003c/span\u003eu) which corelates with the zero-order Korsmeyer-Peppas super case 2 transport model as seen in the drug release kinetic studies in Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. The minimum IBU release in the upper GIT and maximum IBU release in the SCF was found be statistically significant in the best batch F\u003csub\u003eD16\u003c/sub\u003e compared to all single and double coated trial batches. \u003cem\u003eIn vivo\u003c/em\u003e plasma analysis indicates almost negligible IBU in plasma in first 2 hr of the study indicating safe transit of the dual coated pellets through the stomach and initial parts of the intestine. The traces of IBU may be due to the loose surface crystals adhered on the surface of the coated pellets. A very negligible but increasing amount of IBU was found from the 2nd to 9th hr of the study which corelates with the increase in the pH as the coated pellets migrated through the small intestine. This might be attributed to the swelling of the polymeric coating layers as indicated by the drug release kinetics data suggesting Korsmeyer-Peppas super case 2 transport model. A sudden rise in the plasma concentration of IBU after 9th hr indicates degradation of inner time-dependent coating layer and release of the drug. The data also suggests between 2nd to 9th hr the outer pH-dependent layer had first degraded at higher distal small intestinal pH and then the exposed inner time-dependent layer was able to retard the maximum IBU release till 9th hr (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ee) beyond the cecum. The X-ray roentgenography images also shows intact orally administered multi-particulates in stomach after 1.5 hr (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea), in small intestine after 3.5 hr (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eb), transversing through the small intestine and ileocecal segment after 4 hr (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ec) and started to reach colon from cecum after 7th hr (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ed) still intact. After 9th hr post oral administration possible disintegration of coated multi-particulates inside the colon made them undetectable in the subsequent X-ray images thereafter. These X-ray images also collaborate with the \u003cem\u003ein vivo\u003c/em\u003e plasma analysis data as the plasma IBU concentration was still very low between 6th to 9th hr and only had a sudden rise after 9th hr. The maximum release of IBU was observed between 9th and 15th hr with the maximum plasma concentration at 12th hr indicates maximum release of the drug inside the colon. This precise level of colon targeting was found to be relatively better than previous studies with single or double compression coated tablets, single coated multi-particulates or coated hot melt extruded pellets using either pH or GI transit time or combination of pH and colonic bacterial enzymes [\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e, \u003cspan additionalcitationids=\"CR57\" citationid=\"CR56\" class=\"CitationRef\"\u003e56\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e58\u003c/span\u003e].\u003c/p\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eIn conclusion, the potential of dual coated multi-particulates as effective CTDDS has been highlighted. A more precise colon specific release of drug was achieved with a double failsafe mechanism for early dose dumping. The FT-IR and DSC results show stability of IBU inside the polymeric coatings. Uniformity in PSD and higher amount of %-DEE indicates consisted performance of the dual coated pellets. Both \u003cem\u003ein vitro\u003c/em\u003e and \u003cem\u003ein vivo\u003c/em\u003e studies have highlighted the superior colon targeting efficiency of the dual coated pellets. Both the SEM and \u003cem\u003ein vitro\u003c/em\u003e drug release kinetics studies highlighted the zero-order Korsmeyer-Peppas super case 2 transport model which attributes to the swelling, erosion or degradation of polymeric surface coatings. The above findings propose the prospects of inner time- and outer pH-dependent dual-coated preparations as a potentially promising approach for successful CTDDSs containing various other potent drugs, proteins, peptides and chemotherapeutic agents.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNA\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization-Debaprasad Ghosh \u0026amp; Ashu Mittal; Methodology- Debaprasad Ghosh \u0026amp; Deepti Katiyar; Validation and formal analysis- Sanjeev Kumar; Writing\u0026mdash;original draft preparation- Nikhil Kumar Singh \u0026amp; Debaprasad Ghosh; review and editing- Vinay Kumar.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAll authors have read and agreed to the published version of the manuscript.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe Mendeley cite was used for arranging the references of this manuscript. The manuscript was reviewed, and content was edited as per the requirement. The authors take full responsibility for the content of this publication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe animal study was performed with proper approval and permission from the IAEC.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of Competing Interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe research data will be made available on request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAppendixes\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgement\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors acknowledge the valuable support from the KIET School of Pharmacy, Ghaziabad.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eChourasia MK, Jain SK. Pharmaceutical approaches to colon targeted drug delivery systems. J Pharm Pharm Sci. 2003;6(1):33\u0026ndash;66. \u003c/li\u003e\n\u003cli\u003ePatel MM, Amin AF. Formulation and development of release modulated colon targeted system of meloxicam for potential application in the prophylaxis of colorectal cancer. Drug Deliv. 2011 May;18(4):281\u0026ndash;93. \u003c/li\u003e\n\u003cli\u003eHibberd AA, Lyra A, Ouwehand AC, Rolny P, Lindegren H, Cedg\u0026aring;rd L, et al. Intestinal microbiota is altered in patients with colon cancer and modified by probiotic intervention. BMJ Open Gastroenterol. 2017;4(1):e000145. \u003c/li\u003e\n\u003cli\u003eKang RK, Mishr N, Rai VK. Guar Gum Micro-particles for Targeted Co-delivery of Doxorubicin and Metformin HCL for Improved Specificity and Efficacy Against Colon Cancer: In Vitro and In Vivo Studies. AAPS PharmSciTech. 2020 Feb 3;21(2):48. \u003c/li\u003e\n\u003cli\u003eNicze M, Bor\u0026oacute;wka M, Dec A, Niemiec A, Bułdak Ł, Okopień B. The Current and Promising Oral Delivery Methods for Protein- and Peptide-Based Drugs. Int J Mol Sci. 2024 Jan 9;25(2):815. \u003c/li\u003e\n\u003cli\u003eYuan H, Guo C, Liu L, Zhao L, Zhang Y, Yin T, et al. Progress and prospects of polysaccharide-based nanocarriers for oral delivery of proteins/peptides. Carbohydr Polym. 2023 Jul;312:120838. \u003c/li\u003e\n\u003cli\u003ede Alencar RG, de Oliveira AC, Lima EM, da Cunha-Filho MSS, Taveira SF, Marreto RN. Compacted Multiparticulate Systems for Colon-Specific Delivery of Ketoprofen. AAPS PharmSciTech. 2017 Aug;18(6):2260\u0026ndash;8. \u003c/li\u003e\n\u003cli\u003eDey N, Majumdar S, Rao M. Multiparticulate Drug Delivery Systems for Controlled Release. Tropical Journal of Pharmaceutical Research. 2008 Sep 11;7(3). \u003c/li\u003e\n\u003cli\u003eMoutaharrik S, Maroni A, Melocchi A, Zema L, Foppoli A, Cerea M, et al. Oral colon delivery platform based on a novel combination approach: Design concept and preliminary evaluation. J Drug Deliv Sci Technol. 2021 Dec;66:102919. \u003c/li\u003e\n\u003cli\u003eLu E, Li S, Wang Z. Biorelevant test for supersaturable formulation. Asian J Pharm Sci. 2017 Jan;12(1):9\u0026ndash;20. \u003c/li\u003e\n\u003cli\u003eHeni Rachmawati, Diky Mudhakir, Janti Kusuma. Combination of inulin-shellac as a unique coating formulation for design of colonic delivery dosage form of ibuprofen. International Journal of Research in Pharmaceutical Sciences. 2012;3(1):17\u0026ndash;23. \u003c/li\u003e\n\u003cli\u003eBodmeier R, Chen H. Preparation and characterization of microspheres containing the anti-inflammatory agents, indomethacin, ibuprofen, and ketoprofen. Journal of Controlled Release. 1989 Nov;10(2):167\u0026ndash;75. \u003c/li\u003e\n\u003cli\u003eMajumdar S, Roy S, Ghosh B. Design and gamma scintigraphic evaluation of colon specific pectin-EC pellets of secnidazole prepared by powder layering technology. 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Application of Liquisolid Pellets Technology for Improving Dissolution of Posaconazole: A DoE Based Process Optimization. J Pharm Innov. 2024 Jun 24;19(3):23. \u003c/li\u003e\n\u003cli\u003eChandiran Irisappan S, Pavan Kumar B, Narasimha Jayaveera K. Characterization of Glibenclamide loaded cellulose acetate microparticles prepared by an emulsion solvent evaporation method. J Pharm Res. 2013 Aug;7(8):766\u0026ndash;73. \u003c/li\u003e\n\u003cli\u003eSingh SK, Yadav AK, Prudhviraj G, Gulati M, Kaur P, Vaidya Y. A novel dissolution method for evaluation of polysaccharide based colon specific delivery systems: A suitable alternative to animal sacrifice. Eur J Pharm Sci. 2015 Jun 20;73:72\u0026ndash;80. \u003c/li\u003e\n\u003cli\u003eYadav A, Sadora M, Singh S, Gulati M, Maharshi P, Sharma A, et al. Novel biorelevant dissolution medium as a prognostic tool for polysaccharide-based colon-targeted drug delivery system. 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Intelligent Pharmacy. 2024 Jun;2(3):339\u0026ndash;45. \u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Ibuprofen, colon targeted drug delivery, Eudragit L100, Eudragit S100, hydroxypropyl cellulose, ethyl cellulose","lastPublishedDoi":"10.21203/rs.3.rs-8691710/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8691710/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe purpose of the current novel study is to develop dual-coated multi-particulates with a combination of time-dependent inner and pH-dependent outer coating layers to control the release of the entrapped drug from the ascending colon onwards. Ibuprofen-loaded pellets prepared via powder layering technology were coated initially with time-dependent hydroxypropyl cellulose and ethyl cellulose-based inner polymeric layers and afterwards with the Eudragit L100 and Eudragit S100 based outer pH-dependent coating layers and evaluated. The best double coated batch showed nominal \u003cem\u003ein vitro\u003c/em\u003e release of 6.163\u0026thinsp;\u0026plusmn;\u0026thinsp;0.227% in simulated upper GI conditions, with surface morphology collaborating with kinetics data. \u003cem\u003eIn-vivo\u003c/em\u003e animal X-Ray Roentgenography and plasma analysis studies revealed intact multi-particulates arriving inside the colon with maximum plasma concentration of 5.97\u0026thinsp;\u0026plusmn;\u0026thinsp;0.41 \u0026micro;g/ml (C\u003csub\u003emax\u003c/sub\u003e), retarded till 12th hr (T\u003csub\u003emax\u003c/sub\u003e). Results suggest that these dual-coated multi-particulates can be more efficient for colon specific targeting of various potent drugs.\u003c/p\u003e","manuscriptTitle":"A Novel Inner Time and Outer pH-Dependent Dual Coated Multi-Particulate Approach for Colon Specific Delivery of Ibuprofen Beyond Ileocecal Segment in Reduced Colonic Bacterial Diversity","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-23 09:30:20","doi":"10.21203/rs.3.rs-8691710/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"2debb9f7-4cbc-42e1-8dd1-0ac4a22efcb9","owner":[],"postedDate":"February 23rd, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-04-28T00:53:58+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-23 09:30:20","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8691710","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8691710","identity":"rs-8691710","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}