Design and Evaluation of β-Cyclodextrin Nanosponges for Enhanced Oral Delivery of Eltrombopag Using a Quality by Design Approach

Design and Evaluation of β-Cyclodextrin Nanosponges for Enhanced Oral Delivery of Eltrombopag Using a Quality by Design Approach | 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 Design and Evaluation of β-Cyclodextrin Nanosponges for Enhanced Oral Delivery of Eltrombopag Using a Quality by Design Approach Amol R. Pawar¹, Nidhi P. Shah², Ujashkumar Shah³ This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8830792/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 Purpose Eltrombopag is an orally active thrombopoietin receptor agonist whose clinical performance is limited by poor aqueous solubility and variable gastrointestinal absorption caused by chelation with dietary cations. The present study was undertaken to develop and optimize β-cyclodextrin-based nanosponge carriers to improve the solubility, dissolution behavior, and oral delivery of Eltrombopag using a systematic Quality by Design (QbD) approach. Methods β-Cyclodextrin nanosponges loaded with Eltrombopag were prepared using different cross-linking agents and optimized through a Taguchi L9 experimental design. The effects of formulation and process variables on critical quality attributes, including particle size, drug entrapment efficiency, and in vitro drug release, were systematically investigated. The optimized formulation was characterized using Fourier-transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, dynamic light scattering, scanning electron microscopy, phase-solubility analysis, and in vitro dissolution studies. Results The optimized nanosponge formulation demonstrated nanoscale particle size with narrow size distribution, high drug entrapment efficiency, and a marked improvement in dissolution behavior compared to the pure drug. Compatibility studies confirmed the absence of chemical interaction between Eltrombopag and formulation excipients, while morphological evaluation revealed a porous nanosponge architecture conducive to drug encapsulation. Phase-solubility analysis showed a linear enhancement in drug solubility, and in vitro dissolution studies indicated sustained and diffusion-controlled drug release. Stability studies confirmed acceptable physicochemical stability of the optimized formulation. Conclusion The QbD-guided development of β-cyclodextrin nanosponges successfully improved the solubility and controlled release of Eltrombopag. This nanosponge-based delivery system offers a promising strategy for enhancing the oral bioavailability of dissolution-limited drugs and minimizing absorption variability associated with dietary interactions. Cyclodextrin nanosponges Quality by Design Solubility enhancement Oral drug delivery Controlled drug release Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 1. Introduction Eltrombopag is a small-molecule orally active thrombopoietin receptor agonist that is applied in treating chronic immune thrombocytopenia, severe aplastic anemia, and thrombocytopenia caused by chronic hepatitis C infection. The drug stimulates its pharmacological action on the selective stimulation of the c-Mpl receptor on megakaryocyte progenitor cells, leading to the platelet production by megakaryopoiesis stimulation [ 1 , 2 ]. Although oral administration offers clear therapeutic convenience compared with injectable biologics, formulation-related challenges, particularly inconsistent gastrointestinal absorption, can adversely affect the clinical performance of Eltrombopag [ 3 ]. The fluctuation in oral absorption may have a direct effect on systemic exposure, platelet response, and dose titration during prolonged therapy and so it is imperative to develop formulation strategies that guarantee predictable bioavailability and consistent treatment effects [ 4 ]. Eltrombopag is not aqueously soluble over physiological pH and its systemic exposure is largely dissolution-limited with a high percentage oral absorption [ 5 ]. The drug shows a very low solubility in aqueous buffers and a relatively high solubility in organic solvents, which means that it is hydrophobic and that the drug will precipitate during gastrointestinal fluids [ 6 ]. These limits of solubility can lead to incomplete solubility, delayed absorption, and high inter-individual pharmacokinetic variability of the drug after oral administration. Moreover, the low wettability and potential aggregation of Eltrombopag in aqueous conditions may negatively influence stability and reproducibility of the formulations, which makes it more difficult to develop dosage forms that may be administered chronically [ 7 ]. Drug delivery systems that are based on nanotechnology have become useful in enhancing the solubility, rate of dissolution and bioavailability of poorly water-soluble drugs [ 8 ]. Of these systems, cyclodextrin-based nanosponges have received a lot of attention owing to its highly porous, cross-linked, three-dimensional polymeric nature that allows encapsulation through both inclusion and non-inclusion processes of hydrophobic drug molecules [ 9 , 10 ]. The cavities present in the nanosponge wall allow the dispersion of the molecules, the decrease in drug crystallinity, the diffusion-controlled release, and β-cyclodextrin nanosponges are especially favorable in the use of oral drug delivery [ 11 , 12 ]. Nanosponge systems also provide better physicochemical stability and protection of entrapped drugs against early degradation in the environment and gastrointestinal environment besides improving the solubility [ 13 ]. By changing the density of the cross-linking and processing conditions, the porous polymeric framework can be used to control drug loading capacity and drug release kinetics [ 14 ]. The features allow the formulation scientists to design nanosponge architectures towards the desired therapeutic target whilst preserving scalability and reproducibility during fabrication [ 15 , 24 , 35 ]. However, the performance of nanosponge can be strongly dependent on the composition of formulations and the processing parameters that require the utilisation of systematic optimisation strategies to assure homogenisation of quality and predictable behaviour [ 16 ]. Quality by Design (QbD) is a scientific risk-based approach to developing pharmaceuticals that focuses on pre-assigned quality goals, a detailed appreciation of material properties and statistical management of process variability [ 17 ]. QbD incorporates experimental design techniques, Quality by Design (QbD) is a risk- and science-based pharmaceutical development method that focuses attention on pre-determined quality targets of the product, in-depth knowledge of the properties of materials and process variability [ 17 , 18 , 36 , 37 , 38 ]. QbD framework combines the use of experimental design, risk assessment, and multivariate statistical analysis to determine the key parameters of formulation and process that can affect critical quality attributes (CQAs) that include particle size, porosity, drug loading efficiency, and release behavior [ 19 , 20 , 39 , 45 , 46 , 47 , 48 ] 2. Materials and Methods 2.1 Materials Eltrombopag was utilized as the active drug substance in the creation of nanosponges compositions, where the polymeric scaffold is β-cyclodextrin. The cross-linking agents, that is, diphenyl carbonate (DPC) and carbonyldiimidazole (CDI), as well as citric acid, were chosen to create the nanosponges. In the preparation of analytical methods and sample processing, methanol and other analytical-grade solvents were used. The reagents and chemicals were of analytical grade, and they were added without further purification measures. 2.2 Preformulation Studies Preformulation studies were carried out to determine the main physicochemical and powder properties of Eltrombopag prior to its inclusion into nanosponges. The studies provided the necessary knowledge about the stability of the drug, solubility profile, lipophilicity, and handling characteristics, thus educating the design of the formulation, processing capability, and expected drug performance [ 21 ]. 2.2.1 Melting Point and Physical Appearance A small amount of finely powdered and dried Eltrombopag was filled into a clean capillary tube (2–3 mm height) and placed in the apparatus. The instrument is switched on and heated rapidly at first, then slowly at about 1–2°C per minute near the expected melting point. The compound was found as a reddish-brown powder with a slight characteristic smell and bitter taste, as well as possessing amorphous to semi-crystalline structures [ 22 ]. 2.2.2 Partition Coefficient To determine the lipophilicity and permeability of Eltrombopag, the partition coefficient (n-octanol/phosphate buffer, pH 7.4) shake flask method was used to evaluate the lipophilicity of Eltrombopag and its permeability through the membrane. Before the experiment, n-octanol was mixed with phosphate buffer (pH 7.4) to achieve a phase equilibrium. An equal portion of equilibrated aqueous and organic phases was transferred into a stoppered container, and a known quantity of Eltrombopag was put in. The mixture was then vigorously shaken over a defined time to enable complete parting of the drug in each of the two phases and then left to stand until the clear separation of the phases was achieved. Both samples, the n-octanol phase and the aqueous phase were then separated and sampled carefully and then spectrophotometrically analyzed at the known λmax of Eltrombopag. The logP value was determined by dividing the concentration of Eltrombopag in the aqueous with the concentration of Eltrombopag in the n-octanol phase and the percentage difference between these two concentration levels was calculated and was referred to as the partition coefficient (P) [ 23 ]. 2.2.3 Solubility Profiling Solubility experiment was conducted to establish the equilibrium solubility of Eltrombopag in different aqueous buffers and organic solvents. A certain amount of drug was added to each solvent system and constantly stirred due to a set temperature until all was saturated. Suspensions were clarified to eliminate undissolved particles and the clarified products were studied by use of UV-visible spectrophotometry [ 24 ]. 2.2.4 Micromeritic Properties The micro-meritic behavior of Eltrombopag powder was measured to determine the flow and packing behavior of Eltrombopag powder with respect to formulation processing. Bulk density- For bulk density, a known mass of powder was carefully transferred to a graduated cylinder and the initial untapped volume was noted. Tapped density was determined by tapping a cylinder of the same height until a constant volume was recorded and this constant volume was noted. The angle of repose was measured through the fixed funnel technique by letting the powder fall through a funnel onto a smooth surface in the form of a cone. The radius and height of the heap were measured and the angle of repose was determined using the normal mathematical equation. Based on the bulk and tapped density measurements, Carr index and Hausner ratio were determined to measure compressibility of powder and friction between particles and so determine the flow behaviour of Eltrombopag powder [ 21 ]. 2.3 Analytical Method Development A UV-vis spectrophotometric technique was created in the quantitative determination of Eltrombopag during solubility studies, drug loading analysis and in vitro release testing. The appropriate solvent system was chosen depending on the solubility as well as stability of the drug. Eltrombopag was mixed with methanol and scanned within the wavelength spectrum of 200-400nm with the aid of a UV-Visible spectrophotometer to identify the maximum absorbance wavelength (λmax). Eltrombopag standard stock solutions were made and diluted to give a range of working solutions in the linear range of concentration. Each solution was then measured in terms of absorbance at the chosen λmax with methanol as the blank. The calibration curve was developed with the help of plotting the absorbance versus the concentration, and the linearity of the method was assessed. The method developed had good reproducibility and was applicable in quantitative estimation during the study UV-visible absorbance measurements were carried out using a UV-visible spectrophotometer (UV-1800, Shimadzu, Japan) [ 25 ]. 2.3.1 Determination of Maximum Absorption Wavelength (λmax) A stock solution of Eltrombopag was made by dissolving 10 mg of the drug in 10 mL of methanol to produce the drug in 1000 µg/mL concentration. The stock solution was further diluted with methanol to get a working solution of 100 µg/mL. The unknown solution was analyzed in the wavelength span of 200-400nm with a UV-visible spectrophotometer with the blank being methanol. Eltrombopag was observed to show a specific absorption peak at 247 nm, and this absorption peak was chosen as the set analytical wavelength (λmax) to all the further quantitative analysis to be as sensitive and reproducible as possible [ 26 ]. 2.3.2 Calibration Curve Development Eltrombopag has a calibration curve that was prepared using standard solutions in the 5–30 µg/mL concentration range. Absorbance of individual solutions was taken at 247nm with methanol as the blank. They exhibited a linear relationship between the concentration and the absorbance within the studied range and the correlation coefficient (R²) was found to be over 0.99, which indicated a good linearity. Quantitative determination of drug content, entrapment efficiency and in vitro drug release studies were then determined using the calibration curve [ 25 ]. 2.4 Drug-Excipient Compatibility Studies Compatibility examinations on drugs and excipients were conducted to determine potential physicochemical reactions between Eltrombopag and formulation excipients that may affect the stability of the drug, its encapsulation efficiency, or release pattern. The infrared spectroscopy (FTIR) and X-ray diffraction (XRD), as well as differential scanning calorimetry (DSC), were used to determine the molecular integrity, crystallinity, and thermal behavior of the drug at the presence of excipients [ 27 ]. 2.4.1 Fourier Transform Infrared (FTIR) Analysis Compatibility examinations on drugs and excipients were conducted to determine potential physicochemical reactions between Eltrombopag and formulation excipients that may affect the stability of the drug, its encapsulation efficiency, or release pattern. The infrared spectroscopy (FTIR) and X-ray diffraction (XRD), as well as differential scanning calorimetry (DSC), were used to determine the molecular integrity, crystallinity, and thermal behavior of the drug at the presence of excipients [ 28 ]. 2.4.2 X-ray Diffraction (XRD) The Eltrombopag and its physical mixtures with excipients were investigated using X-ray diffraction to determine whether they are crystalline or amorphous. The samples were subjected to the analysis of an X-ray diffractometer with Cu-Kα radiation (λ = 1.5406 Å). Diffractograms were recorded over a diffraction angle (2θ) range of 5°-50°. The nanosponge formulations were evaluated based on the position, intensity, and broadening of characteristic diffraction peaks, intensity and broadening of the characteristic peaks to measure the extent of crystallinity alteration after nanosponge formulation [ 29 ]. 2.4.3 Differential Scanning Calorimetry (DSC) The thermal properties and solubility of Eltrombopag with formulation excipients were analyzed using the technique of differential scanning calorimetry. About 5 mg of these samples were precisely weighed and placed in aluminum pans and heated at a constant rate in an inert atmosphere. The comparison of thermograms was made with regards to the endotherms several melting changes, peak shifts, and enthalpy alterations to identify potential drug-excipient interactions and thermal stability variations [ 30 ]. 2.5 Preparation of Nanosponges The cross-linking reagents employed in the preparation of β-cyclodextrin nanosponges included diphenyl carbonate (DPC), carbonyldiimidazole (CDI), and citric acid, which were reacted with the functional groups of β-cyclodextrin at pre-established molar ratios under controlled thermal conditions. The reaction was conducted in dimethylformamide with continuous magnetic stirring at 80°C for 5 h. After completion of the reaction, the solid mass obtained was allowed to cool to room temperature, crushed, and washed successively with deionized water followed by ethanol to remove unreacted reagents and reaction by-products. The purified nanosponges were dried in a hot-air oven at 60°C for 12 h and stored in a desiccator until further use [ 31 ]. 2.5.1 Cross-Linking Process The chosen cross-linking agents, diphenyl carbonate (DPC), carbonyldiimidazole (CDI), and citric acid were reacted with β-cyclodextrin in controlled thermal conditions to create a three-dimensional nanosponge network. The mixture of the components was kept at a controlled temperature and stirred to ensure that the cross-linking and network were formed between the various polymers. The mass of nanosponge formed was then purified to eliminate any unreacted reagents and by-products and dried and then the size was reduced to generate uniform nanosponge particle. Density of cross-linking was calculated to give enough porosity, mechanical stability and drug holding capacity [ 31 , 32 ]. 2.5.2 Drug Loading Procedure Drug loading and entrapment efficiency were evaluated to assess the ability of β-cyclodextrin nanosponges to incorporate Eltrombopag. A known quantity of drug-loaded nanosponges was accurately weighed and dissolved in a suitable solvent to ensure complete extraction of the entrapped drug from the nanosponge matrix. The dispersion was then centrifuged, and the clear supernatant obtained was analyzed spectrophotometrically at 247 nm to determine the drug content. The percentage drug loading and entrapment efficiency were calculated using the following equations [ 33 ]. Drug loading (%) = (Amount of drug present in nanosponges / Total weight of drug-loaded nanosponges) × 100 Entrapment efficiency (%) = (Amount of drug entrapped / Total amount of drug used) × 100 2.6 Quality by Design The systematic development, optimization, and reproducibility of Eltrombopag-loaded β-cyclodextrin nanosponges were achieved using a Quality by Design (QbD) approach. The QbD framework was employed to identify critical quality attributes (CQAs), evaluate formulation and process variables, and establish an effective design space to achieve the desired product performance [ 34 ]. Table 1 Quality Target Product Profile (QTPP) for Eltrombopag-loaded β-cyclodextrin nanosponges Attribute Target Dosage Form Nanosponges (powder) Route of Administration Oral or topical (dispersible) Drug Content 1 g per batch Particle Size 150–300 nm Entrapment Efficiency ≥ 70% Drug Release (6 h) ≥ 80% Stability No physical/chemical degradation Table 2 Critical Quality Attributes (CQAs) identified for Eltrombopag nanosponge formulation CQA Importance Particle size (nm) High Entrapment efficiency (%) High Drug release (6 h) High Yield (%) Medium Table 3 Independent Variables and Responses Factor Code Factor Name Levels A Drug:Polymer Ratio 1:5, 1:10, 1:15 B Cross-linker Type DPC, CDI, Citric Acid C Stirring Speed (rpm) 500, 800, 1000 2.6.1 Quality Target Product Profile (QTPP) The Quality Target Product Profile (QTPP) describes the desired quality characteristics of the final formulation based on its intended clinical use and performance. In the present study, the QTPP for Eltrombopag-loaded β-cyclodextrin nanosponges included suitability for oral administration, enhancement of apparent solubility, nanoscale particle size, adequate drug entrapment efficiency, controlled drug release behavior, physicochemical stability, and reproducible manufacturing feasibility. These attributes were selected to ensure consistent therapeutic performance and reliable formulation quality (Table 1 ). 2.6.2 Critical Quality Attributes (CQAs) Critical Quality Attributes (CQAs) are the physical, chemical, or biological properties of a formulation that must be controlled within appropriate limits to ensure the desired product quality. In the present study, the CQAs identified for Eltrombopag-loaded β-cyclodextrin nanosponges included particle size and size distribution, drug entrapment efficiency, drug loading capacity, surface morphology, and in vitro drug release behavior. These attributes were considered critical because they directly influence solubility enhancement, formulation stability, and drug release performance. Therefore, careful monitoring and control of these CQAs were essential during formulation development to achieve consistent product quality and predictable therapeutic performance (Table 2 ). 2.6.3 Independent Variables Based on preliminary risk assessment and scientific understanding of the formulation process, key formulation and process parameters were selected as independent variables for optimization. In this study, the independent variables included the drug-to-polymer ratio, the type of cross-linking agent (diphenyl carbonate, carbonyldiimidazole, and citric acid), and the stirring speed used during nanosponge preparation. These variables were selected because of their expected influence on nanosponge formation, porosity, particle size distribution, drug encapsulation efficiency, and in vitro drug release behavior. Systematic variation of these parameters enabled evaluation of their individual and combined effects on the identified critical quality attributes (Table 3 ). 2.6.4 Taguchi Experimental Design Matrix - L9 A Taguchi L9 orthogonal array design was employed to systematically study the effects of the selected independent variables at three different levels while minimizing the number of experimental runs. The design allowed evaluation of three factors with three levels each using nine experimental formulations, thereby ensuring efficient use of materials and time. The experimental design enabled assessment of the influence of formulation and process variables on critical quality attributes such as particle size, drug entrapment efficiency, and in vitro drug release. Statistical analysis of the experimental responses was used to identify the optimal formulation conditions and to reduce variability in the formulation process. 2.7 Evaluation Parameters The prepared Eltrombopag-loaded β-cyclodextrin nanosponges were evaluated to determine key quality characteristics including particle size distribution, surface charge, drug entrapment efficiency, drug loading, surface morphology, and in vitro drug release behavior. These parameters are critical for assessing formulation stability, solubility enhancement, and overall performance of the nanosponge system. 2.7.1 Particle Size Analysis (Dynamic Light Scattering) Particle size distribution and polydispersity index of the nanosponge formulations were determined using dynamic light scattering (DLS). An appropriate amount of nanosponge dispersion was diluted with filtered distilled water to obtain a clear suspension. The diluted samples were sonicated briefly to prevent aggregation and equilibrated at room temperature prior to analysis. Measurements were carried out at a fixed scattering angle, and all analyses were performed in triplicate to ensure reproducibility of the results. Particle size and polydispersity index were measured using a dynamic light scattering analyzer (Zetasizer Nano ZS, Malvern Instruments Ltd., UK) [ 40 ]. 2.7.2 Entrapment Efficiency Entrapment efficiency was determined to evaluate the proportion of Eltrombopag successfully incorporated within the nanosponge matrix. A known amount of drug-loaded nanosponges was dispersed in a suitable solvent and centrifuged to separate unentrapped drug. The supernatant was analyzed spectrophotometrically at 247 nm to quantify the amount of free drug present. Entrapment efficiency was calculated based on the difference between the total drug added and the unentrapped drug fraction [ 41 ]. 2.7.3 Drug Loading Drug loading was determined by accurately weighing a fixed amount of drug-loaded nanosponges and dissolving it in methanol to ensure complete release of the entrapped drug. The resulting solution was analyzed using a UV-visible spectrophotometer at 247 nm. Drug loading was expressed as the percentage of drug present relative to the total weight of the nanosponge formulation [ 41 ]. 2.7.4 Zeta Potential Zeta potential measurements were performed to determine the surface charge and colloidal stability of the nanosponge formulations. The nanosponge dispersion was diluted with distilled water and transferred to a zeta potential cell. Measurements were carried out using a particle size analyzer equipped for electrophoretic mobility determination. Zeta potential measurements were performed using the same instrument equipped with electrophoretic light scattering capability (Zetasizer Nano ZS, Malvern Instruments Ltd., UK) [ 42 ]. 2.7.5 Scanning Electron Microscopy (SEM) Morphology The surface morphology of the optimized nanosponge formulation was examined using scanning electron microscopy. Samples were mounted on aluminum stubs using double-sided adhesive tape and coated with a thin layer of gold under vacuum. SEM images were recorded at different magnifications to observe particle shape, surface texture, and porosity. Scanning electron microscopy images were obtained using a scanning electron microscope (JSM-7610F, JEOL Ltd., Japan) [ 43 ]. 2.7.6 In Vitro Drug Release Test In vitro drug release studies were performed using a USP Type II (paddle) dissolution apparatus. An accurately weighed amount of drug-loaded nanosponges was placed in 900 mL of phosphate buffer (pH 6.8) maintained at 37 ± 0.5°C, with a paddle rotation speed of 50 rpm. Samples were withdrawn at predetermined time intervals and replaced with an equal volume of fresh dissolution medium to maintain sink conditions. The withdrawn samples were analyzed spectrophotometrically at 247 nm, and cumulative drug release was calculated as a function of time. Dissolution studies were performed using a USP Type II dissolution apparatus (Electrolab TDT-08L, Mumbai, India) [ 44 ]. 2.8 Statistical Analysis The statistical analysis was done with the help of Design-Expert® software (Version X). Mean ± standard deviation (SD) were used to represent experimental data. The analysis of variance (ANOVA) was used to determine the significance of formulation variable and the difference was statistically significant at p < 0.05. 3. Results and Discussion 3.1 Preformulation Characterization Preformulation characterization was carried out to establish the baseline physicochemical and micromeritic properties of Eltrombopag prior to nanosponge formulation. These studies provided essential information regarding the drug's physical appearance, solubility behavior, lipophilicity, and flow characteristics, which are critical for formulation design and processing considerations. Table 4 Physical and physicochemical properties of Eltrombopag Parameter Observation Colour Reddish-brown powder Odour Odourless or faint characteristic odour Taste Bitter Appearance Amorphous to slightly crystalline powder Melting Point (°C) 242°C Partition Coefficient (Log P) 1.60 Table 5 Solubility profile of Eltrombopag in different media Buffer / Solvent Tentative Solubility (µg/mL) 0.1 N HCl (pH ≈ 1) 5 (practically insoluble; denatures) Acetate buffer pH 4.5 4 (very low) Phosphate buffer pH 6.8 5 (very low soluble) Phosphate buffer pH 7.4 6 (very low soluble) Purified Water 7 (very low soluble) Ethanol 6 (very low) Methanol 10 (soluble) DMSO 6 (low soluble) Table 6 Micromeritic properties of Eltrombopag powder (mean ± SD, n = 3) Parameter Reading (Mean ± SD) Bulk Density (g/mL) 0.610 ± 0.003 Tapped Density (g/mL) 0.732 ± 0.003 Angle of Repose (°) 32.1 ± 0.67 Carr's Index (%) 16.69 ± 0.02 Hausner's Ratio 1.22 ± 0.64 3.1.1 Physical Properties Eltrombopag was observed as a reddish-brown powder with a characteristic odor and bitter taste. The drug exhibited an amorphous to slightly crystalline nature and showed a melting point of 242°C, indicating good thermal stability and purity. The partition coefficient (log P) value of 1.60 suggested moderate lipophilicity, which supports its affinity toward hydrophobic carrier systems such as β-cyclodextrin nanosponges (Table 4 ). 3.1.2 Solubility Behaviour Solubility studies demonstrated that Eltrombopag possessed very low solubility in aqueous media across different physiological pH conditions, including acidic and neutral buffers. In contrast, comparatively higher solubility was observed in organic solvents such as methanol. This solubility profile confirms the hydrophobic nature of Eltrombopag and explains its dissolution-limited absorption following oral administration. The poor aqueous solubility highlights the necessity for formulation strategies aimed at enhancing apparent solubility and dissolution performance (Table 5 ). 3.1.3 Flow Properties The micromeritic evaluation revealed that Eltrombopag powder exhibited acceptable flow properties, as indicated by bulk density, tapped density, angle of repose, Carr's index, and Hausner's ratio values. These parameters suggest that the drug possesses suitable handling and processing characteristics, which are favorable for nanosponge preparation and subsequent formulation steps (Table 6 ). 3.2 Results of the Analytical Validation The UV-visible spectrophotometric method developed for the estimation of Eltrombopag showed reliable analytical performance within the studied concentration range. Eltrombopag exhibited a distinct maximum absorbance at 247 nm, which was selected for quantitative analysis. The calibration curve constructed over the concentration range of 5–30 µg/mL demonstrated a linear relationship between absorbance and concentration, with a correlation coefficient (R²) greater than 0.99, indicating good linearity. The consistency of absorbance values across replicate measurements confirms the suitability of the method for quantitative estimation of Eltrombopag in solubility studies, drug loading determination, and in vitro drug release analysis. The calibration data are presented in Table 7 , and the corresponding calibration curve is illustrated in Fig. 2 . Table 7 Calibration curve data of Eltrombopag at 247 nm Concentration (µg/mL) Absorbance 0 0.000 5 0.105 10 0.215 15 0.350 20 0.462 25 0.590 30 0.702 The simplicity of the sample-preparation method by nature combined with a consistent baseline and reproducible absorbance values meant that there was minimum variability in the data analysis and that the method was rather easily applicable across the course of the formulation-development cycle. As described, the method was found to be sufficiently sensitive to detect small changes in concentration and maintain a reliable analysis of repeat measurements. 3.3 Compatibility Analysis Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) were employed to assess the compatibility of Eltrombopag with formulation excipients and to confirm its physicochemical stability. The FTIR spectra of pure Eltrombopag and its physical mixtures exhibited the characteristic functional group peaks of the drug without any noticeable shifting, disappearance, or appearance of new peaks, indicating the absence of chemical interaction and confirming molecular-level compatibility. The FTIR spectra of pure Eltrombopag, physical mixture, and the optimized nanosponge formulation are presented in Fig. 3 . XRD diffractograms revealed that the characteristic diffraction peaks of Eltrombopag were retained without the formation of new crystalline phases or significant distortion of peak patterns. This observation confirms that the crystalline integrity of the drug was preserved and that no polymorphic transformation occurred as a result of interaction with excipients or processing conditions. The X-ray diffraction patterns of pure Eltrombopag and the optimized nanosponge formulation are shown in Fig. 4 . DSC thermograms showed the presence of the characteristic melting endotherm of Eltrombopag with no significant shift in melting temperature or change in enthalpy. The absence of additional thermal events further supports thermal compatibility and the lack of solid-state interactions between the drug and excipients. Collectively, the FTIR, XRD, and DSC results demonstrate that Eltrombopag remains chemically and physically stable within the nanosponge formulation system, thereby validating the selection of excipients and the applied processing conditions. The DSC thermograms of pure Eltrombopag and the optimized nanosponge formulation are illustrated in Fig. 5 . 3.4 Optimization Results Phase solubility studies demonstrated a strong linear relationship between Eltrombopag solubility and nanosponge concentration, with a high correlation coefficient (R² = 0.9998; p < 0.0001), confirming an AL-type Higuchi-Connors profile. One-way ANOVA revealed a statistically significant effect of nanosponge concentration on drug solubility, indicating effective interaction between Eltrombopag and the nanosponge matrix. Based on the optimization study, formulation F7 was identified as the optimal batch, providing a balanced combination of particle size, drug entrapment efficiency, and in vitro drug release. The optimized nanosponge formulation exhibited improved solubilization capacity, structural stability, and reproducibility. Overall, the results support the application of a Quality by Design approach for systematic formulation optimization and highlight the potential of nanosponge systems to enhance the delivery performance of Eltrombopag. Table 8 A Taguchi L9 experimental design for Eltrombopag nanosponge formulations Batch Drug:Polymer Cross-linker Speed (rpm) F1 1:5 DPC 500 F2 1:5 CDI 800 F3 1:5 Citric Acid 1000 F4 1:10 DPC 800 F5 1:10 CDI 1000 F6 1:10 Citric Acid 500 F7 1:15 DPC 1000 F8 1:15 CDI 500 F9 1:15 Citric Acid 800 Table 8 B Experimental responses obtained for Eltrombopag nanosponge formulations Batch EE (%) Size (nm) Release (%) Yield (%) F1 72 215 83 85 F2 68 245 78 83 F3 66 268 81 80 F4 75 200 87 87 F5 70 235 82 86 F6 73 220 84 88 F7 78 195 89 89 F8 72 210 85 88 F9 74 205 86 90 Table 9 Phase solubility data of Eltrombopag in the presence of β-cyclodextrin nanosponges Nanosponges Conc. (% w/v) Mean Solubility (µg/mL) Enhancement 0.00 21 ± 1 1.00 0.25 34 ± 1 1.62 0.50 48 ± 2 2.29 0.75 62 ± 2 2.95 1.00 77 ± 2 3.67 1.25 91 ± 2 4.33 Particle size analysis of the Eltrombopag-loaded β-cyclodextrin nanosponges revealed that the formulations were within the nanometer range with a relatively narrow size distribution. The optimized formulation exhibited a mean particle size suitable for oral delivery applications. The polydispersity index values indicated a uniform particle size distribution, suggesting effective formulation control during nanosponge preparation. The nanoscale size of the formulations is expected to contribute to improved surface area and enhanced dissolution behavior, which may support better solubility and absorption of Eltrombopag. 3.4.2 Effect of Cross-Linker Zeta potential measurements were carried out to evaluate the surface charge and colloidal stability of the nanosponge formulations. The optimized formulation exhibited a negative zeta potential value, indicating adequate electrostatic repulsion between particles. The observed surface charge suggests that the nanosponge dispersion possesses acceptable stability, thereby reducing the likelihood of particle aggregation during storage and handling. 3.4.3 Effect of Stirring Speed Entrapment efficiency studies demonstrated that Eltrombopag was effectively incorporated within the β-cyclodextrin nanosponge matrix. The optimized formulation showed a high percentage of drug entrapment, indicating efficient interaction between the drug and the nanosponge network. Drug loading values further confirmed the suitability of the formulation approach, as a sufficient amount of Eltrombopag was retained within the nanosponges to achieve the desired therapeutic performance. The combined results reflect the effectiveness of the selected formulation parameters in achieving reproducible and efficient drug incorporation. 3.4.4 Response Surface Interpretation Response surface analysis was used to visualize the interactive effects of polymer ratio, cross-linker type, and stirring speed on key quality attributes such as particle size, entrapment efficiency, and drug release behavior. The response plots indicated that the formulation variables did not act independently but exhibited combined synergistic and antagonistic effects on nanosponge characteristics. The response surfaces identified optimal operational regions where desirable formulation performance was achieved. The smooth and consistent trends observed across the response plots confirm the robustness of the developed design space and validate the effectiveness of the Quality by Design-based optimization approach in achieving predictable and reproducible nanosponge performance. 3.5 Particle Size, Entrapment Efficiency and Drug Release Particle size analysis confirmed the formation of nanoscale Eltrombopag-loaded β-cyclodextrin nanosponges with a uniform size distribution in the optimized batch (F7). The nanoscale particle size is favorable for increasing surface area and improving wettability and dissolution behavior, thereby contributing to enhanced apparent solubility and controlled drug release. Entrapment efficiency analysis demonstrated effective incorporation of Eltrombopag within the porous nanosponge matrix. The high entrapment efficiency observed for the optimized formulation indicates stable accommodation of the drug within the polymer network, which is essential for maintaining consistent drug content and ensuring reproducible release performance. In vitro drug release studies showed sustained and controlled release of Eltrombopag from the nanosponge formulation, with improved dissolution behavior compared to the pure drug. This release pattern can be attributed to diffusion-controlled release from the porous nanosponge architecture while preserving structural integrity during dissolution. Overall, these findings support the suitability of nanosponge carriers for enhancing the delivery performance of Eltrombopag. Table 10 In vitro drug release profile of Eltrombopag-loaded β-cyclodextrin nanosponges Batch 1 h 2 h 4 h 6 h 8 h 12 h F1 18 34 58 83 92 97 F2 15 30 52 78 88 94 F3 17 32 55 81 89 95 F4 20 38 64 87 94 98 F5 18 34 60 82 91 96 F6 19 36 62 84 92 97 F7 22 42 70 89 96 99 F8 20 39 65 85 94 98 F9 21 40 67 86 95 98 3.6 SEM Morphology Interpretation SEM micrographs of the optimized nanosponge formulation revealed discrete, porous, and nearly spherical particles with uniform surface morphology and minimal aggregation. The observed surface features confirm the successful formation of nanosponges, while SEM analysis primarily provides morphological information rather than quantitative drug distribution. 3.7 Statistical Validation and Model Adequacy The reliability and strength of the optimization model used in development of the formulations were statistically validated. The phase-solubility studies displayed a strong linear correlation, (R² = 0.9998, p < 0.0001) thus supporting the predictive relationship between nanosponges concentration and enhancement of solubility. Analysis of one-way ANOVA demonstrated that the variables of formulation presented in the model had a statistically significant contribution to the model, with an extremely high F-value of 37235.12, which proves that the model is significant and the variability of the experiment is minimal. The release profile kinetic modelling suggested that the optimized formulation fits the Higuchi diffusion model (R² = 0.987), which in turn validated diffusion-controlled drug release. The released exponent of the Korsmeyer-Peppas (n = 0.61) indicated that it is related to anomalous transport that comprises diffusion as well as the polymer relaxation processes. The presence of high correlation coefficients and a consistent model fitting shows sufficient predictability as well as reliability of the model. Overall, the statistical verification proves the adequacy, reproducibility, and strength of the nanosponges formulation to be adequate, reproducible, and robust. These statistical methods were incorporated, which also guaranteed the scientific credibility of the method and allowed the rational optimisation of the formulation parameters. Table 11 Confirmatory batch validation results for optimized Eltrombopag nanosponge formulation Parameter Predicted Experimental % Error Particle Size (nm) 280 285 ± 18 1.79 Entrapment Efficiency (%) 76.5 78.2 ± 1.4 2.22 Drug Release at 6 h (%) 85.0 87.1 ± 1.9 2.47 Zeta Potential (mV) −30.0 −32.0 ± 1.1 6.67 4. Conclusion In the present study, Eltrombopag-loaded β-cyclodextrin nanosponges were successfully developed and optimized using a Quality by Design approach. Preformulation and compatibility studies confirmed the physicochemical stability of Eltrombopag within the nanosponge system. The optimized formulation exhibited nanoscale particle size, high entrapment efficiency, and controlled drug release behavior. Phase solubility and response surface analyses demonstrated a significant improvement in solubility and validated the robustness of the developed design space. The sustained and reproducible release profile observed for the optimized nanosponge formulation highlights the potential of nanosponge carriers to enhance the oral delivery performance of Eltrombopag. Overall, the findings support the applicability of QbD-guided nanosponge systems as a promising strategy for improving solubility and dissolution-limited drugs. Declarations Authors' Contributions Amol R. Pawar conducted the primary research work, including formulation development, Quality by Design optimization, data analysis, and manuscript drafting. Nidhi P. Shah provided technical input and assisted in data interpretation and manuscript review. Ujashkumar Shah supervised the study and contributed to critical revision and final approval of the manuscript. All authors approved the final version. Ethics Consent and Approval to Take Part This study did not involve human participants or live animals. Therefore, ethical approval and informed consent were not required. Conflict of Interest The authors do not have any conflict of interest. Funding Statement This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Availability of Data Statement The data created and/or processed in the course of the ongoing research can be obtained by the authorized writer on a case-by-case basis. Generative AI and AI-Assisted Technologies in Writing During the preparation of this manuscript, artificial intelligence-based tools were used only to support linguistic refinement and formatting. The authors independently reviewed all scientific content, verified the accuracy of the data, and ensured the integrity of the analysis and conclusions. References Bussel JB, Cheng G, Saleh MN, et al. Eltrombopag for the treatment of chronic immune thrombocytopenic purpura. N Engl J Med. 2007; 357:2237-2247. McHutchison JW, Dusheiko EL, Shiffman M, et al. Eltrombopag for thrombocytopenia in patients with cirrhosis associated with hepatitis C. N Engl J Med. 357 (2007) 2227-2236. McDonald K, Fields S. Pharmacokinetics and clinical application of Eltrombopag. Clin Pharmacokinet. 51 (2012) 715-729. Kuter A. Biology and clinical application of thrombopoietin receptor agonists. Int J Hematol. 96 (2012) 707-719. Ghanima J, Bussel T. Eltrombopag: A review of safety and efficacy in thrombocytopenia. Drug Des Devel Ther. 13 (2019) 2291-2303. Hiasa M, Abe T. Solubility and dissolution challenges in oral delivery of hydrophobic drugs. J Pharm Sci. 104 (2015) 2767-2778. Lipinski H. Drug-like properties and solubility limitations in oral delivery. Adv Drug Deliv Rev. 23 (2001) 3-25. Singh R, Lillard JW. Nanoparticle-based drug delivery systems. Exp Mol Pathol. 2009;86:215-223. Trotta F, Zanetti M. Cyclodextrin-based nanosponges for drug delivery. Pharmaceutics. 4 (2012) 241-274. Swaminathan A, Cavalli A, Trotta F. Cyclodextrin-based nanosponges: A versatile platform for drug delivery. J Incl Phenom Macrocycl Chem. 80 (2014) 1-15. Loftsson T, Brewster ME. Pharmaceutical applications of cyclodextrins. J Pharm Sci. 85 (1996) 1017-1025. Davis M. Cyclodextrin chemistry and drug complexation. Chem Rev. 104 (2004) 357-373. Caldera P, Trotta F, Cavalli A. Inclusion properties of cyclodextrin nanosponges. Carbohydr Polym. 89 (2012) 123-130. Pushpalatha S, Selvamuthukumar M. Nanosponges for pharmaceutical drug delivery systems. Int J Pharm Sci Rev Res. 36 (2016) 30-38. Higuchi P, Connors T. Phase solubility techniques. Adv Anal Chem Instrum. 4 (1965) 117-212. Yu J, Lionberger R, Raw S, et al. Applications of Quality by Design in pharmaceutical development. AAPS J. 10 (2008) 321-333. International Council for Harmonisation. ICH Q8(R2): Pharmaceutical Development. Geneva; 2009. ICH Q9. Quality Risk Management. International Conference on Harmonization, Geneva, 2005. Lionberger R. Quality by Design: Concepts for ANDA development. Pharm Res. 25 (2008) 781-791. Lawrence S, Rees S. Micro- and nano-structured drug delivery systems for solubility enhancement. Adv Drug Deliv Rev. 45 (2000) 89-121. Aulton ME, Taylor KMG. Pharmaceutics: The Design and Manufacture of Medicines. 4th ed. London: Churchill Livingstone Elsevier; 2013. Swarbrick J, Boylan JC. Encyclopedia of pharmaceutical technology: Preformulation and physicochemical characterization of drug substances. Marcel Dekker Inc., New York, 2002. Avdeef A. Absorption and drug development: Solubility, permeability and charge state. Wiley-Interscience, Hoboken, 2nd Ed., 2012. Florence AT, Attwood D. Physicochemical principles of pharmacy: In manufacture, formulation and clinical use. Pharmaceutical Press, London, 6th Ed., 2015. Chatwal G, Anand S. Instrumental methods of chemical analysis. Himalaya Publishing House, Mumbai, 5th Ed., 2014. Skoog DA, Holler FJ, Crouch SR. Principles of instrumental analysis. Cengage Learning, Boston, 6th Ed., 2007. Coates J. Interpretation of infrared spectra: A practical approach. Encycl Anal Chem. (2000) 10815-10837. Stuart B. Infrared spectroscopy: Fundamentals and applications. Wiley, Chichester, 2004. Cullity BD, Stock SR. Elements of X-ray diffraction. Prentice Hall, New Jersey, 3rd Ed., 2001. Brown ME. Introduction to thermal analysis: Techniques and applications. Kluwer Academic Publishers, Dordrecht, 2nd Ed., 2001. Trotta F, Tumiatti D, Cavalli R. Cross-linked cyclodextrin nanosponges as drug carriers. J Incl Phenom Macrocycl Chem. 56 (2006) 209-213. Swaminathan A, Cavalli A, Trotta F. Cyclodextrin-based nanosponges for drug delivery and targeting. Int J Pharm. 454 (2013) 189-198. Selvamuthukumar M, Anandam S, Krishnamoorthy K. Nanosponges: A novel class of drug delivery system. J Pharm Sci Res. 4 (2012) 1721-1726. Singh V, Sharma R. Development of cyclodextrin-based nanosponges for solubility enhancement of poorly soluble drugs. Int J Pharm. 514 (2016) 271-279. Celebioglu A, Uyar T. Electrospun nanofibers for drug delivery and molecular encapsulation. J Incl Phenom Macrocycl Chem. 88 (2017) 1-15. Pushpalatha S, Selvamuthukumar M. Optimization of nanosponge formulations using design of experiments approach. Drug Dev Ind Pharm. 43 (2017) 1476-1485. Jain P, Patil R. Enhancement of dissolution behavior of BCS class II drugs using nanosponge carriers. Powder Technol. 345 (2019) 368-376. Taguchi G. Introduction to quality engineering: Designing quality into products and processes. Asian Productivity Organization, Tokyo, 1986. Malvern P. Dynamic light scattering: Principles and applications in particle size analysis. Malvern Instruments Technical Note, Worcestershire, 2012. Bhattacharjee R. DLS and zeta potential -- What they are and what they are not?. J Control Release. 235 (2016) 337-351. Abdelwahed A, Degobert G, Stainmesse S, Fessi H. Freeze-drying of nanoparticles: Formulation, process and storage considerations. Adv Drug Deliv Rev. 58 (2006) 1688-1713. Honary S, Zahir F. Effect of zeta potential on the properties of nano-drug delivery systems -- A review. Trop J Pharm Res. 12 (2013) 255-264. Goldstein L, Newbury DE, Echlin P, et al. Scanning electron microscopy and X-ray microanalysis. Springer, New York, 3rd Ed., 2003. Wagner JG. Interpretation of percent dissolved-time plots derived from in vitro testing of conventional tablets and capsules. J Pharm Sci. 58 (1969) 1253-1257. Montgomery DC. Design and analysis of experiments. John Wiley & Sons, New York, 8th Ed., 2013. Steel RG, Torrie JH. Principles and procedures of statistics: A biometrical approach. McGraw-Hill, New York, 3rd Ed., 1997. Taguchi G, Chowdhury S, Taguchi S. Robust engineering: Learn how to boost quality while reducing costs and time to market. McGraw-Hill, New York, 2000. Anderson DR, Sweeney DJ, Williams TA. Statistics for business and economics. Cengage Learning, Boston, 11th Ed., 2012. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-8830792","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":619673822,"identity":"39a79d6a-9b79-4bc7-9699-32d32409a6c4","order_by":0,"name":"Amol R. Pawar¹","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4UlEQVRIiWNgGAWjYHACxgOMDSCa+eADIMnDR4weqBa2ZAOQFjYStPCYSYB1ElLOP+3wgcOFO+zyddvPmFV+zbGTYWNgfvjoBh4tErfTEg7PPJNsue1MWtlt2W3JQIexGRvn4LPmdo7BYd42ZgOzA8nbbktuYwZq4WGTxqdFHqKl3sDs/AOzYslt9YS1GEC0HDYwu5Fixvhx22HCWgzBfmk7DtTyLFmacdtxHjZmAn6Ru5188HFhWzXQYckHP/7cVm3Pz9788DFe7wMBM5zBg8IlRgvjDyJUj4JRMApGwcgDACUgS3FKMWSzAAAAAElFTkSuQmCC","orcid":"","institution":"Institute of Pharmaceutical Education and Research","correspondingAuthor":true,"prefix":"","firstName":"Amol","middleName":"R.","lastName":"Pawar¹","suffix":""},{"id":619673824,"identity":"eee621eb-80db-4069-b09c-66dcd4875674","order_by":1,"name":"Nidhi P. Shah²","email":"","orcid":"","institution":"Nootan Pharmacy College, Sankalchand Patel University","correspondingAuthor":false,"prefix":"","firstName":"Nidhi","middleName":"P.","lastName":"Shah²","suffix":""},{"id":619673825,"identity":"707056f4-9c79-41cb-b314-50f3efd273b7","order_by":2,"name":"Ujashkumar Shah³","email":"","orcid":"","institution":"Nootan Pharmacy College, Sankalchand Patel University","correspondingAuthor":false,"prefix":"","firstName":"Ujashkumar","middleName":"","lastName":"Shah³","suffix":""}],"badges":[],"createdAt":"2026-02-09 13:08:51","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8830792/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8830792/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":106615245,"identity":"d43d23c7-30be-408d-b3f1-3a209afb46d3","added_by":"auto","created_at":"2026-04-10 13:02:52","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":544820,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8830792/v1/a4ad8cfa852c7ae28bd13d62.png"},{"id":106725653,"identity":"7364047c-a7c1-4b57-b6ff-9dea1420e439","added_by":"auto","created_at":"2026-04-12 18:33:23","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":99216,"visible":true,"origin":"","legend":"\u003cp\u003eCalibration curve of Eltrombopag obtained at 247 nm using UV-visible spectrophotometry.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8830792/v1/45a93884ca6139327db2051f.png"},{"id":106728894,"identity":"babb2a5d-c3e2-4483-b756-295828b6ddbd","added_by":"auto","created_at":"2026-04-12 18:45:54","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":99607,"visible":true,"origin":"","legend":"\u003cp\u003eFTIR spectra of (a) pure Eltrombopag, (b) physical mixture with β-cyclodextrin, and (c) Eltrombopag-loaded β-cyclodextrin nanosponges.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-8830792/v1/efeb98ece58646c3afeb7107.png"},{"id":106615247,"identity":"498c973d-b93e-444b-8a59-ea20afc4c2a1","added_by":"auto","created_at":"2026-04-10 13:02:52","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":63057,"visible":true,"origin":"","legend":"\u003cp\u003eX-ray diffraction patterns of (a) pure Eltrombopag, (b) physical mixture with β-cyclodextrin, and (c) Eltrombopag-loaded β-cyclodextrin nanosponges.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-8830792/v1/9b8d35249dfd4a10e2d47aff.png"},{"id":107704773,"identity":"5026468c-ed88-425a-9d75-3e4771b74261","added_by":"auto","created_at":"2026-04-24 08:57:44","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":113019,"visible":true,"origin":"","legend":"\u003cp\u003eDifferential scanning calorimetry thermograms of (a) pure Eltrombopag, (b) physical mixture with β-cyclodextrin, and (c) Eltrombopag-loaded β-cyclodextrin nanosponges\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-8830792/v1/fae0cbaca27aa96a74be6767.png"},{"id":106726550,"identity":"a13b3ec3-7870-4c59-a175-8069f84dad96","added_by":"auto","created_at":"2026-04-12 18:36:30","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":85635,"visible":true,"origin":"","legend":"\u003cp\u003ePhase-solubility diagram of Eltrombopag in the presence of β-cyclodextrin nanosponges.\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-8830792/v1/3dc5a1dc2852d8356e8b6a8f.png"},{"id":106615249,"identity":"9adeb93d-755b-4dbb-bd92-7135a01ffe0c","added_by":"auto","created_at":"2026-04-10 13:02:52","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":173446,"visible":true,"origin":"","legend":"\u003cp\u003eIn vitro drug release profiles of Eltrombopag-loaded β-cyclodextrin nanosponge formulations.\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-8830792/v1/8de76e557c8f48b6e3af61f2.png"},{"id":106725652,"identity":"3de5ea59-5ff8-4217-bb76-19fb40f9ab9c","added_by":"auto","created_at":"2026-04-12 18:33:23","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":449971,"visible":true,"origin":"","legend":"\u003cp\u003eScanning electron micrographs of Eltrombopag-loaded β-cyclodextrin nanosponges at different magnifications. (a) SEM image at 5,000× magnification showing porous agglomerated nanosponges structure. (b) SEM image at 10,000× magnification highlighting surface roughness and nanoscale pores. (c) SEM image at 5,000× magnification illustrating uniform particle aggregation and porous texture. (d) SEM image at 10,000× magnification revealing fine surface morphology and interconnected pore network. [FIGURES TO BE INSERTED]\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-8830792/v1/aefbe083dd26e4786d7eb666.png"},{"id":106615253,"identity":"eee2cbbd-2b18-4e6d-8fc9-efebc261d23e","added_by":"auto","created_at":"2026-04-10 13:02:52","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":111038,"visible":true,"origin":"","legend":"\u003cp\u003eUnnumbered image in the Results and Discussion section.\u003c/p\u003e","description":"","filename":"unnumberfig.png","url":"https://assets-eu.researchsquare.com/files/rs-8830792/v1/cecad5ed7b2008f33f435bb8.png"},{"id":108181055,"identity":"4e166d23-2670-495e-a8b8-b948403561f2","added_by":"auto","created_at":"2026-04-30 08:56:43","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2162905,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8830792/v1/61d5642b-00b5-4131-9ec6-f6d7172fd6ea.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Design and Evaluation of β-Cyclodextrin Nanosponges for Enhanced Oral Delivery of Eltrombopag Using a Quality by Design Approach","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eEltrombopag is a small-molecule orally active thrombopoietin receptor agonist that is applied in treating chronic immune thrombocytopenia, severe aplastic anemia, and thrombocytopenia caused by chronic hepatitis C infection. The drug stimulates its pharmacological action on the selective stimulation of the c-Mpl receptor on megakaryocyte progenitor cells, leading to the platelet production by megakaryopoiesis stimulation [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Although oral administration offers clear therapeutic convenience compared with injectable biologics, formulation-related challenges, particularly inconsistent gastrointestinal absorption, can adversely affect the clinical performance of Eltrombopag [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The fluctuation in oral absorption may have a direct effect on systemic exposure, platelet response, and dose titration during prolonged therapy and so it is imperative to develop formulation strategies that guarantee predictable bioavailability and consistent treatment effects [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Eltrombopag is not aqueously soluble over physiological pH and its systemic exposure is largely dissolution-limited with a high percentage oral absorption [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. The drug shows a very low solubility in aqueous buffers and a relatively high solubility in organic solvents, which means that it is hydrophobic and that the drug will precipitate during gastrointestinal fluids [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. These limits of solubility can lead to incomplete solubility, delayed absorption, and high inter-individual pharmacokinetic variability of the drug after oral administration. Moreover, the low wettability and potential aggregation of Eltrombopag in aqueous conditions may negatively influence stability and reproducibility of the formulations, which makes it more difficult to develop dosage forms that may be administered chronically [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Drug delivery systems that are based on nanotechnology have become useful in enhancing the solubility, rate of dissolution and bioavailability of poorly water-soluble drugs [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Of these systems, cyclodextrin-based nanosponges have received a lot of attention owing to its highly porous, cross-linked, three-dimensional polymeric nature that allows encapsulation through both inclusion and non-inclusion processes of hydrophobic drug molecules [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. The cavities present in the nanosponge wall allow the dispersion of the molecules, the decrease in drug crystallinity, the diffusion-controlled release, and β-cyclodextrin nanosponges are especially favorable in the use of oral drug delivery [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Nanosponge systems also provide better physicochemical stability and protection of entrapped drugs against early degradation in the environment and gastrointestinal environment besides improving the solubility [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eBy changing the density of the cross-linking and processing conditions, the porous polymeric framework can be used to control drug loading capacity and drug release kinetics [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. The features allow the formulation scientists to design nanosponge architectures towards the desired therapeutic target whilst preserving scalability and reproducibility during fabrication [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. However, the performance of nanosponge can be strongly dependent on the composition of formulations and the processing parameters that require the utilisation of systematic optimisation strategies to assure homogenisation of quality and predictable behaviour [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eQuality by Design (QbD) is a scientific risk-based approach to developing pharmaceuticals that focuses on pre-assigned quality goals, a detailed appreciation of material properties and statistical management of process variability [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. QbD incorporates experimental design techniques, Quality by Design (QbD) is a risk- and science-based pharmaceutical development method that focuses attention on pre-determined quality targets of the product, in-depth knowledge of the properties of materials and process variability [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. QbD framework combines the use of experimental design, risk assessment, and multivariate statistical analysis to determine the key parameters of formulation and process that can affect critical quality attributes (CQAs) that include particle size, porosity, drug loading efficiency, and release behavior [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e, \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e, \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e, \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e, \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e]\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"2. Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Materials\u003c/h2\u003e \u003cp\u003eEltrombopag was utilized as the active drug substance in the creation of nanosponges compositions, where the polymeric scaffold is β-cyclodextrin. The cross-linking agents, that is, diphenyl carbonate (DPC) and carbonyldiimidazole (CDI), as well as citric acid, were chosen to create the nanosponges. In the preparation of analytical methods and sample processing, methanol and other analytical-grade solvents were used. The reagents and chemicals were of analytical grade, and they were added without further purification measures.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Preformulation Studies\u003c/h2\u003e \u003cp\u003ePreformulation studies were carried out to determine the main physicochemical and powder properties of Eltrombopag prior to its inclusion into nanosponges. The studies provided the necessary knowledge about the stability of the drug, solubility profile, lipophilicity, and handling characteristics, thus educating the design of the formulation, processing capability, and expected drug performance [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section3\"\u003e \u003ch2\u003e2.2.1 Melting Point and Physical Appearance\u003c/h2\u003e \u003cp\u003eA small amount of finely powdered and dried Eltrombopag was filled into a clean capillary tube (2\u0026ndash;3 mm height) and placed in the apparatus. The instrument is switched on and heated rapidly at first, then slowly at about 1\u0026ndash;2\u0026deg;C per minute near the expected melting point. The compound was found as a reddish-brown powder with a slight characteristic smell and bitter taste, as well as possessing amorphous to semi-crystalline structures [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003e2.2.2 Partition Coefficient\u003c/h2\u003e \u003cp\u003eTo determine the lipophilicity and permeability of Eltrombopag, the partition coefficient (n-octanol/phosphate buffer, pH 7.4) shake flask method was used to evaluate the lipophilicity of Eltrombopag and its permeability through the membrane. Before the experiment, n-octanol was mixed with phosphate buffer (pH 7.4) to achieve a phase equilibrium.\u003c/p\u003e \u003cp\u003eAn equal portion of equilibrated aqueous and organic phases was transferred into a stoppered container, and a known quantity of Eltrombopag was put in. The mixture was then vigorously shaken over a defined time to enable complete parting of the drug in each of the two phases and then left to stand until the clear separation of the phases was achieved.\u003c/p\u003e \u003cp\u003eBoth samples, the n-octanol phase and the aqueous phase were then separated and sampled carefully and then spectrophotometrically analyzed at the known λmax of Eltrombopag. The logP value was determined by dividing the concentration of Eltrombopag in the aqueous with the concentration of Eltrombopag in the n-octanol phase and the percentage difference between these two concentration levels was calculated and was referred to as the partition coefficient (P) [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section3\"\u003e \u003ch2\u003e2.2.3 Solubility Profiling\u003c/h2\u003e \u003cp\u003eSolubility experiment was conducted to establish the equilibrium solubility of Eltrombopag in different aqueous buffers and organic solvents. A certain amount of drug was added to each solvent system and constantly stirred due to a set temperature until all was saturated. Suspensions were clarified to eliminate undissolved particles and the clarified products were studied by use of UV-visible spectrophotometry [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section3\"\u003e \u003ch2\u003e2.2.4 Micromeritic Properties\u003c/h2\u003e \u003cp\u003eThe micro-meritic behavior of Eltrombopag powder was measured to determine the flow and packing behavior of Eltrombopag powder with respect to formulation processing. Bulk density- For bulk density, a known mass of powder was carefully transferred to a graduated cylinder and the initial untapped volume was noted. Tapped density was determined by tapping a cylinder of the same height until a constant volume was recorded and this constant volume was noted. The angle of repose was measured through the fixed funnel technique by letting the powder fall through a funnel onto a smooth surface in the form of a cone. The radius and height of the heap were measured and the angle of repose was determined using the normal mathematical equation. Based on the bulk and tapped density measurements, Carr index and Hausner ratio were determined to measure compressibility of powder and friction between particles and so determine the flow behaviour of Eltrombopag powder [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Analytical Method Development\u003c/h2\u003e \u003cp\u003eA UV-vis spectrophotometric technique was created in the quantitative determination of Eltrombopag during solubility studies, drug loading analysis and in vitro release testing. The appropriate solvent system was chosen depending on the solubility as well as stability of the drug. Eltrombopag was mixed with methanol and scanned within the wavelength spectrum of 200-400nm with the aid of a UV-Visible spectrophotometer to identify the maximum absorbance wavelength (λmax).\u003c/p\u003e \u003cp\u003eEltrombopag standard stock solutions were made and diluted to give a range of working solutions in the linear range of concentration. Each solution was then measured in terms of absorbance at the chosen λmax with methanol as the blank. The calibration curve was developed with the help of plotting the absorbance versus the concentration, and the linearity of the method was assessed. The method developed had good reproducibility and was applicable in quantitative estimation during the study UV-visible absorbance measurements were carried out using a UV-visible spectrophotometer (UV-1800, Shimadzu, Japan) [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e2.3.1 Determination of Maximum Absorption Wavelength (λmax)\u003c/h2\u003e \u003cp\u003eA stock solution of Eltrombopag was made by dissolving 10 mg of the drug in 10 mL of methanol to produce the drug in 1000 \u0026micro;g/mL concentration. The stock solution was further diluted with methanol to get a working solution of 100 \u0026micro;g/mL. The unknown solution was analyzed in the wavelength span of 200-400nm with a UV-visible spectrophotometer with the blank being methanol. Eltrombopag was observed to show a specific absorption peak at 247 nm, and this absorption peak was chosen as the set analytical wavelength (λmax) to all the further quantitative analysis to be as sensitive and reproducible as possible [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e \u003ch2\u003e2.3.2 Calibration Curve Development\u003c/h2\u003e \u003cp\u003eEltrombopag has a calibration curve that was prepared using standard solutions in the 5\u0026ndash;30 \u0026micro;g/mL concentration range. Absorbance of individual solutions was taken at 247nm with methanol as the blank. They exhibited a linear relationship between the concentration and the absorbance within the studied range and the correlation coefficient (R\u0026sup2;) was found to be over 0.99, which indicated a good linearity. Quantitative determination of drug content, entrapment efficiency and in vitro drug release studies were then determined using the calibration curve [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Drug-Excipient Compatibility Studies\u003c/h2\u003e \u003cp\u003eCompatibility examinations on drugs and excipients were conducted to determine potential physicochemical reactions between Eltrombopag and formulation excipients that may affect the stability of the drug, its encapsulation efficiency, or release pattern. The infrared spectroscopy (FTIR) and X-ray diffraction (XRD), as well as differential scanning calorimetry (DSC), were used to determine the molecular integrity, crystallinity, and thermal behavior of the drug at the presence of excipients [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e].\u003c/p\u003e \u003cdiv id=\"Sec13\" class=\"Section3\"\u003e \u003ch2\u003e2.4.1 Fourier Transform Infrared (FTIR) Analysis\u003c/h2\u003e \u003cp\u003eCompatibility examinations on drugs and excipients were conducted to determine potential physicochemical reactions between Eltrombopag and formulation excipients that may affect the stability of the drug, its encapsulation efficiency, or release pattern. The infrared spectroscopy (FTIR) and X-ray diffraction (XRD), as well as differential scanning calorimetry (DSC), were used to determine the molecular integrity, crystallinity, and thermal behavior of the drug at the presence of excipients [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section3\"\u003e \u003ch2\u003e2.4.2 X-ray Diffraction (XRD)\u003c/h2\u003e \u003cp\u003eThe Eltrombopag and its physical mixtures with excipients were investigated using X-ray diffraction to determine whether they are crystalline or amorphous. The samples were subjected to the analysis of an X-ray diffractometer with Cu-Kα radiation (λ\u0026thinsp;=\u0026thinsp;1.5406 \u0026Aring;). Diffractograms were recorded over a diffraction angle (2θ) range of 5\u0026deg;-50\u0026deg;. The nanosponge formulations were evaluated based on the position, intensity, and broadening of characteristic diffraction peaks, intensity and broadening of the characteristic peaks to measure the extent of crystallinity alteration after nanosponge formulation [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section3\"\u003e \u003ch2\u003e2.4.3 Differential Scanning Calorimetry (DSC)\u003c/h2\u003e \u003cp\u003eThe thermal properties and solubility of Eltrombopag with formulation excipients were analyzed using the technique of differential scanning calorimetry. About 5 mg of these samples were precisely weighed and placed in aluminum pans and heated at a constant rate in an inert atmosphere.\u003c/p\u003e \u003cp\u003eThe comparison of thermograms was made with regards to the endotherms several melting changes, peak shifts, and enthalpy alterations to identify potential drug-excipient interactions and thermal stability variations [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e2.5 Preparation of Nanosponges\u003c/h2\u003e \u003cp\u003eThe cross-linking reagents employed in the preparation of β-cyclodextrin nanosponges included diphenyl carbonate (DPC), carbonyldiimidazole (CDI), and citric acid, which were reacted with the functional groups of β-cyclodextrin at pre-established molar ratios under controlled thermal conditions.\u003c/p\u003e \u003cp\u003eThe reaction was conducted in dimethylformamide with continuous magnetic stirring at 80\u0026deg;C for 5 h. After completion of the reaction, the solid mass obtained was allowed to cool to room temperature, crushed, and washed successively with deionized water followed by ethanol to remove unreacted reagents and reaction by-products. The purified nanosponges were dried in a hot-air oven at 60\u0026deg;C for 12 h and stored in a desiccator until further use [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e \u003cdiv id=\"Sec17\" class=\"Section3\"\u003e \u003ch2\u003e2.5.1 Cross-Linking Process\u003c/h2\u003e \u003cp\u003eThe chosen cross-linking agents, diphenyl carbonate (DPC), carbonyldiimidazole (CDI), and citric acid were reacted with β-cyclodextrin in controlled thermal conditions to create a three-dimensional nanosponge network. The mixture of the components was kept at a controlled temperature and stirred to ensure that the cross-linking and network were formed between the various polymers. The mass of nanosponge formed was then purified to eliminate any unreacted reagents and by-products and dried and then the size was reduced to generate uniform nanosponge particle. Density of cross-linking was calculated to give enough porosity, mechanical stability and drug holding capacity [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section3\"\u003e \u003ch2\u003e2.5.2 Drug Loading Procedure\u003c/h2\u003e \u003cp\u003eDrug loading and entrapment efficiency were evaluated to assess the ability of β-cyclodextrin nanosponges to incorporate Eltrombopag. A known quantity of drug-loaded nanosponges was accurately weighed and dissolved in a suitable solvent to ensure complete extraction of the entrapped drug from the nanosponge matrix. The dispersion was then centrifuged, and the clear supernatant obtained was analyzed spectrophotometrically at 247 nm to determine the drug content. The percentage drug loading and entrapment efficiency were calculated using the following equations [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDrug loading (%) = (Amount of drug present in nanosponges / Total weight of drug-loaded nanosponges) \u0026times; 100\u003c/p\u003e \u003cp\u003eEntrapment efficiency (%) = (Amount of drug entrapped / Total amount of drug used) \u0026times; 100\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003e2.6 Quality by Design\u003c/h2\u003e \u003cp\u003eThe systematic development, optimization, and reproducibility of Eltrombopag-loaded β-cyclodextrin nanosponges were achieved using a Quality by Design (QbD) approach. The QbD framework was employed to identify critical quality attributes (CQAs), evaluate formulation and process variables, and establish an effective design space to achieve the desired product performance [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\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\u003eQuality Target Product Profile (QTPP) for Eltrombopag-loaded β-cyclodextrin nanosponges\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAttribute\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTarget\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDosage Form\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNanosponges (powder)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRoute of Administration\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOral or topical (dispersible)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDrug Content\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 g per batch\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParticle Size\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e150\u0026ndash;300 nm\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEntrapment Efficiency\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;70%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDrug Release (6 h)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;80%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStability\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNo physical/chemical degradation\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\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\u003eCritical Quality Attributes (CQAs) identified for Eltrombopag nanosponge formulation\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCQA\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eImportance\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParticle size (nm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEntrapment efficiency (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDrug release (6 h)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHigh\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYield (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMedium\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\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\u003eIndependent Variables and Responses\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFactor Code\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFactor Name\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLevels\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDrug:Polymer Ratio\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1:5, 1:10, 1:15\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eB\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCross-linker Type\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDPC, CDI, Citric Acid\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStirring Speed (rpm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e500, 800, 1000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec20\" class=\"Section3\"\u003e \u003ch2\u003e2.6.1 Quality Target Product Profile (QTPP)\u003c/h2\u003e \u003cp\u003eThe Quality Target Product Profile (QTPP) describes the desired quality characteristics of the final formulation based on its intended clinical use and performance. In the present study, the QTPP for Eltrombopag-loaded β-cyclodextrin nanosponges included suitability for oral administration, enhancement of apparent solubility, nanoscale particle size, adequate drug entrapment efficiency, controlled drug release behavior, physicochemical stability, and reproducible manufacturing feasibility. These attributes were selected to ensure consistent therapeutic performance and reliable formulation quality (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section3\"\u003e \u003ch2\u003e2.6.2 Critical Quality Attributes (CQAs)\u003c/h2\u003e \u003cp\u003eCritical Quality Attributes (CQAs) are the physical, chemical, or biological properties of a formulation that must be controlled within appropriate limits to ensure the desired product quality. In the present study, the CQAs identified for Eltrombopag-loaded β-cyclodextrin nanosponges included particle size and size distribution, drug entrapment efficiency, drug loading capacity, surface morphology, and in vitro drug release behavior.\u003c/p\u003e \u003cp\u003eThese attributes were considered critical because they directly influence solubility enhancement, formulation stability, and drug release performance. Therefore, careful monitoring and control of these CQAs were essential during formulation development to achieve consistent product quality and predictable therapeutic performance (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec22\" class=\"Section3\"\u003e \u003ch2\u003e2.6.3 Independent Variables\u003c/h2\u003e \u003cp\u003eBased on preliminary risk assessment and scientific understanding of the formulation process, key formulation and process parameters were selected as independent variables for optimization. In this study, the independent variables included the drug-to-polymer ratio, the type of cross-linking agent (diphenyl carbonate, carbonyldiimidazole, and citric acid), and the stirring speed used during nanosponge preparation.\u003c/p\u003e \u003cp\u003eThese variables were selected because of their expected influence on nanosponge formation, porosity, particle size distribution, drug encapsulation efficiency, and in vitro drug release behavior. Systematic variation of these parameters enabled evaluation of their individual and combined effects on the identified critical quality attributes (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec23\" class=\"Section3\"\u003e \u003ch2\u003e2.6.4 Taguchi Experimental Design Matrix - L9\u003c/h2\u003e \u003cp\u003eA Taguchi L9 orthogonal array design was employed to systematically study the effects of the selected independent variables at three different levels while minimizing the number of experimental runs. The design allowed evaluation of three factors with three levels each using nine experimental formulations, thereby ensuring efficient use of materials and time.\u003c/p\u003e \u003cp\u003eThe experimental design enabled assessment of the influence of formulation and process variables on critical quality attributes such as particle size, drug entrapment efficiency, and in vitro drug release. Statistical analysis of the experimental responses was used to identify the optimal formulation conditions and to reduce variability in the formulation process.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec24\" class=\"Section2\"\u003e \u003ch2\u003e2.7 Evaluation Parameters\u003c/h2\u003e \u003cp\u003eThe prepared Eltrombopag-loaded β-cyclodextrin nanosponges were evaluated to determine key quality characteristics including particle size distribution, surface charge, drug entrapment efficiency, drug loading, surface morphology, and in vitro drug release behavior. These parameters are critical for assessing formulation stability, solubility enhancement, and overall performance of the nanosponge system.\u003c/p\u003e \u003cdiv id=\"Sec25\" class=\"Section3\"\u003e \u003ch2\u003e2.7.1 Particle Size Analysis (Dynamic Light Scattering)\u003c/h2\u003e \u003cp\u003eParticle size distribution and polydispersity index of the nanosponge formulations were determined using dynamic light scattering (DLS). An appropriate amount of nanosponge dispersion was diluted with filtered distilled water to obtain a clear suspension. The diluted samples were sonicated briefly to prevent aggregation and equilibrated at room temperature prior to analysis.\u003c/p\u003e \u003cp\u003eMeasurements were carried out at a fixed scattering angle, and all analyses were performed in triplicate to ensure reproducibility of the results. Particle size and polydispersity index were measured using a dynamic light scattering analyzer (Zetasizer Nano ZS, Malvern Instruments Ltd., UK) [\u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec26\" class=\"Section3\"\u003e \u003ch2\u003e2.7.2 Entrapment Efficiency\u003c/h2\u003e \u003cp\u003eEntrapment efficiency was determined to evaluate the proportion of Eltrombopag successfully incorporated within the nanosponge matrix. A known amount of drug-loaded nanosponges was dispersed in a suitable solvent and centrifuged to separate unentrapped drug. The supernatant was analyzed spectrophotometrically at 247 nm to quantify the amount of free drug present. Entrapment efficiency was calculated based on the difference between the total drug added and the unentrapped drug fraction [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec27\" class=\"Section3\"\u003e \u003ch2\u003e2.7.3 Drug Loading\u003c/h2\u003e \u003cp\u003eDrug loading was determined by accurately weighing a fixed amount of drug-loaded nanosponges and dissolving it in methanol to ensure complete release of the entrapped drug. The resulting solution was analyzed using a UV-visible spectrophotometer at 247 nm. Drug loading was expressed as the percentage of drug present relative to the total weight of the nanosponge formulation [\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec28\" class=\"Section3\"\u003e \u003ch2\u003e2.7.4 Zeta Potential\u003c/h2\u003e \u003cp\u003eZeta potential measurements were performed to determine the surface charge and colloidal stability of the nanosponge formulations. The nanosponge dispersion was diluted with distilled water and transferred to a zeta potential cell. Measurements were carried out using a particle size analyzer equipped for electrophoretic mobility determination. Zeta potential measurements were performed using the same instrument equipped with electrophoretic light scattering capability (Zetasizer Nano ZS, Malvern Instruments Ltd., UK) [\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec29\" class=\"Section3\"\u003e \u003ch2\u003e2.7.5 Scanning Electron Microscopy (SEM) Morphology\u003c/h2\u003e \u003cp\u003eThe surface morphology of the optimized nanosponge formulation was examined using scanning electron microscopy. Samples were mounted on aluminum stubs using double-sided adhesive tape and coated with a thin layer of gold under vacuum. SEM images were recorded at different magnifications to observe particle shape, surface texture, and porosity. Scanning electron microscopy images were obtained using a scanning electron microscope (JSM-7610F, JEOL Ltd., Japan) [\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec30\" class=\"Section3\"\u003e \u003ch2\u003e2.7.6 In Vitro Drug Release Test\u003c/h2\u003e \u003cp\u003eIn vitro drug release studies were performed using a USP Type II (paddle) dissolution apparatus. An accurately weighed amount of drug-loaded nanosponges was placed in 900 mL of phosphate buffer (pH 6.8) maintained at 37\u0026thinsp;\u0026plusmn;\u0026thinsp;0.5\u0026deg;C, with a paddle rotation speed of 50 rpm.\u003c/p\u003e \u003cp\u003eSamples were withdrawn at predetermined time intervals and replaced with an equal volume of fresh dissolution medium to maintain sink conditions. The withdrawn samples were analyzed spectrophotometrically at 247 nm, and cumulative drug release was calculated as a function of time. Dissolution studies were performed using a USP Type II dissolution apparatus (Electrolab TDT-08L, Mumbai, India) [\u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec31\" class=\"Section2\"\u003e \u003ch2\u003e2.8 Statistical Analysis\u003c/h2\u003e \u003cp\u003eThe statistical analysis was done with the help of Design-Expert\u0026reg; software (Version X). Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD) were used to represent experimental data. The analysis of variance (ANOVA) was used to determine the significance of formulation variable and the difference was statistically significant at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results and Discussion","content":"\u003cdiv id=\"Sec33\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Preformulation Characterization\u003c/h2\u003e \u003cp\u003ePreformulation characterization was carried out to establish the baseline physicochemical and micromeritic properties of Eltrombopag prior to nanosponge formulation. These studies provided essential information regarding the drug's physical appearance, solubility behavior, lipophilicity, and flow characteristics, which are critical for formulation design and processing considerations.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePhysical and physicochemical properties of Eltrombopag\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eObservation\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eColour\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eReddish-brown powder\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOdour\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOdourless or faint characteristic odour\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTaste\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBitter\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAppearance\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAmorphous to slightly crystalline powder\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMelting Point (\u0026deg;C)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e242\u0026deg;C\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePartition Coefficient (Log P)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.60\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\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSolubility profile of Eltrombopag in different media\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBuffer / Solvent\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTentative Solubility (\u0026micro;g/mL)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.1 N HCl (pH\u0026thinsp;\u0026asymp;\u0026thinsp;1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 (practically insoluble; denatures)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAcetate buffer pH 4.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (very low)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhosphate buffer pH 6.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 (very low soluble)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhosphate buffer pH 7.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 (very low soluble)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePurified Water\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7 (very low soluble)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEthanol\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 (very low)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMethanol\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10 (soluble)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDMSO\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 (low soluble)\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\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMicromeritic properties of Eltrombopag powder (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD, n\u0026thinsp;=\u0026thinsp;3)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eReading (Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBulk Density (g/mL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.610\u0026thinsp;\u0026plusmn;\u0026thinsp;0.003\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTapped Density (g/mL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.732\u0026thinsp;\u0026plusmn;\u0026thinsp;0.003\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAngle of Repose (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e32.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.67\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCarr's Index (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e16.69\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHausner's Ratio\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e1.22\u0026thinsp;\u0026plusmn;\u0026thinsp;0.64\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cdiv id=\"Sec34\" class=\"Section3\"\u003e \u003ch2\u003e3.1.1 Physical Properties\u003c/h2\u003e \u003cp\u003eEltrombopag was observed as a reddish-brown powder with a characteristic odor and bitter taste. The drug exhibited an amorphous to slightly crystalline nature and showed a melting point of 242\u0026deg;C, indicating good thermal stability and purity. The partition coefficient (log P) value of 1.60 suggested moderate lipophilicity, which supports its affinity toward hydrophobic carrier systems such as β-cyclodextrin nanosponges (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec35\" class=\"Section3\"\u003e \u003ch2\u003e3.1.2 Solubility Behaviour\u003c/h2\u003e \u003cp\u003eSolubility studies demonstrated that Eltrombopag possessed very low solubility in aqueous media across different physiological pH conditions, including acidic and neutral buffers. In contrast, comparatively higher solubility was observed in organic solvents such as methanol. This solubility profile confirms the hydrophobic nature of Eltrombopag and explains its dissolution-limited absorption following oral administration. The poor aqueous solubility highlights the necessity for formulation strategies aimed at enhancing apparent solubility and dissolution performance (Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec36\" class=\"Section3\"\u003e \u003ch2\u003e3.1.3 Flow Properties\u003c/h2\u003e \u003cp\u003eThe micromeritic evaluation revealed that Eltrombopag powder exhibited acceptable flow properties, as indicated by bulk density, tapped density, angle of repose, Carr's index, and Hausner's ratio values. These parameters suggest that the drug possesses suitable handling and processing characteristics, which are favorable for nanosponge preparation and subsequent formulation steps (Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec37\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Results of the Analytical Validation\u003c/h2\u003e \u003cp\u003eThe UV-visible spectrophotometric method developed for the estimation of Eltrombopag showed reliable analytical performance within the studied concentration range. Eltrombopag exhibited a distinct maximum absorbance at 247 nm, which was selected for quantitative analysis.\u003c/p\u003e \u003cp\u003eThe calibration curve constructed over the concentration range of 5\u0026ndash;30 \u0026micro;g/mL demonstrated a linear relationship between absorbance and concentration, with a correlation coefficient (R\u0026sup2;) greater than 0.99, indicating good linearity. The consistency of absorbance values across replicate measurements confirms the suitability of the method for quantitative estimation of Eltrombopag in solubility studies, drug loading determination, and in vitro drug release analysis.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe calibration data are presented in Table\u0026nbsp;\u003cspan refid=\"Tab7\" class=\"InternalRef\"\u003e7\u003c/span\u003e, and the corresponding calibration curve is illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab7\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 7\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCalibration curve data of Eltrombopag at 247 nm\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eConcentration (\u0026micro;g/mL)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAbsorbance\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.000\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=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.105\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=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.215\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=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.350\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=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.462\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=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.590\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.702\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\u003eThe simplicity of the sample-preparation method by nature combined with a consistent baseline and reproducible absorbance values meant that there was minimum variability in the data analysis and that the method was rather easily applicable across the course of the formulation-development cycle. As described, the method was found to be sufficiently sensitive to detect small changes in concentration and maintain a reliable analysis of repeat measurements.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec38\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Compatibility Analysis\u003c/h2\u003e \u003cp\u003eFourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) were employed to assess the compatibility of Eltrombopag with formulation excipients and to confirm its physicochemical stability. The FTIR spectra of pure Eltrombopag and its physical mixtures exhibited the characteristic functional group peaks of the drug without any noticeable shifting, disappearance, or appearance of new peaks, indicating the absence of chemical interaction and confirming molecular-level compatibility. The FTIR spectra of pure Eltrombopag, physical mixture, and the optimized nanosponge formulation are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eXRD diffractograms revealed that the characteristic diffraction peaks of Eltrombopag were retained without the formation of new crystalline phases or significant distortion of peak patterns. This observation confirms that the crystalline integrity of the drug was preserved and that no polymorphic transformation occurred as a result of interaction with excipients or processing conditions. The X-ray diffraction patterns of pure Eltrombopag and the optimized nanosponge formulation are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eDSC thermograms showed the presence of the characteristic melting endotherm of Eltrombopag with no significant shift in melting temperature or change in enthalpy. The absence of additional thermal events further supports thermal compatibility and the lack of solid-state interactions between the drug and excipients. Collectively, the FTIR, XRD, and DSC results demonstrate that Eltrombopag remains chemically and physically stable within the nanosponge formulation system, thereby validating the selection of excipients and the applied processing conditions. The DSC thermograms of pure Eltrombopag and the optimized nanosponge formulation are illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec39\" class=\"Section2\"\u003e \u003ch2\u003e3.4 Optimization Results\u003c/h2\u003e \u003cp\u003ePhase solubility studies demonstrated a strong linear relationship between Eltrombopag solubility and nanosponge concentration, with a high correlation coefficient (R\u0026sup2; = 0.9998; p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001), confirming an AL-type Higuchi-Connors profile. One-way ANOVA revealed a statistically significant effect of nanosponge concentration on drug solubility, indicating effective interaction between Eltrombopag and the nanosponge matrix.\u003c/p\u003e \u003cp\u003eBased on the optimization study, formulation F7 was identified as the optimal batch, providing a balanced combination of particle size, drug entrapment efficiency, and in vitro drug release. The optimized nanosponge formulation exhibited improved solubilization capacity, structural stability, and reproducibility. Overall, the results support the application of a Quality by Design approach for systematic formulation optimization and highlight the potential of nanosponge systems to enhance the delivery performance of Eltrombopag.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab8\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 8\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cb\u003eA\u003c/b\u003e Taguchi L9 experimental design for Eltrombopag nanosponge formulations\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBatch\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDrug:Polymer\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCross-linker\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSpeed (rpm)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDPC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCDI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e800\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCitric Acid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDPC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e800\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCDI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCitric Acid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDPC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCDI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e500\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1:15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCitric Acid\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e800\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\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab9\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 8\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u003cb\u003eB\u003c/b\u003e Experimental responses obtained for Eltrombopag nanosponge formulations\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" 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=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBatch\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEE (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSize (nm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eRelease (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eYield (%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e215\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e85\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e245\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e83\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e268\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e80\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e87\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e235\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e86\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e220\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e88\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e195\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e89\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e89\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e210\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e88\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e74\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e205\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e90\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\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab10\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 9\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePhase solubility data of Eltrombopag in the presence of β-cyclodextrin nanosponges\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNanosponges Conc. (% w/v)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean Solubility (\u0026micro;g/mL)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eEnhancement\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e21\u0026thinsp;\u0026plusmn;\u0026thinsp;1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e34\u0026thinsp;\u0026plusmn;\u0026thinsp;1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.62\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e48\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.29\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e0.75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e62\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.95\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e77\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3.67\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e91\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e4.33\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\u003e \u003c/p\u003e \u003cp\u003eParticle size analysis of the Eltrombopag-loaded β-cyclodextrin nanosponges revealed that the formulations were within the nanometer range with a relatively narrow size distribution. The optimized formulation exhibited a mean particle size suitable for oral delivery applications. The polydispersity index values indicated a uniform particle size distribution, suggesting effective formulation control during nanosponge preparation.\u003c/p\u003e \u003cp\u003eThe nanoscale size of the formulations is expected to contribute to improved surface area and enhanced dissolution behavior, which may support better solubility and absorption of Eltrombopag.\u003c/p\u003e \u003cdiv id=\"Sec40\" class=\"Section3\"\u003e \u003ch2\u003e3.4.2 Effect of Cross-Linker\u003c/h2\u003e \u003cp\u003eZeta potential measurements were carried out to evaluate the surface charge and colloidal stability of the nanosponge formulations. The optimized formulation exhibited a negative zeta potential value, indicating adequate electrostatic repulsion between particles. The observed surface charge suggests that the nanosponge dispersion possesses acceptable stability, thereby reducing the likelihood of particle aggregation during storage and handling.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec41\" class=\"Section3\"\u003e \u003ch2\u003e3.4.3 Effect of Stirring Speed\u003c/h2\u003e \u003cp\u003eEntrapment efficiency studies demonstrated that Eltrombopag was effectively incorporated within the β-cyclodextrin nanosponge matrix. The optimized formulation showed a high percentage of drug entrapment, indicating efficient interaction between the drug and the nanosponge network.\u003c/p\u003e \u003cp\u003eDrug loading values further confirmed the suitability of the formulation approach, as a sufficient amount of Eltrombopag was retained within the nanosponges to achieve the desired therapeutic performance. The combined results reflect the effectiveness of the selected formulation parameters in achieving reproducible and efficient drug incorporation.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec42\" class=\"Section3\"\u003e \u003ch2\u003e3.4.4 Response Surface Interpretation\u003c/h2\u003e \u003cp\u003eResponse surface analysis was used to visualize the interactive effects of polymer ratio, cross-linker type, and stirring speed on key quality attributes such as particle size, entrapment efficiency, and drug release behavior. The response plots indicated that the formulation variables did not act independently but exhibited combined synergistic and antagonistic effects on nanosponge characteristics.\u003c/p\u003e \u003cp\u003eThe response surfaces identified optimal operational regions where desirable formulation performance was achieved. The smooth and consistent trends observed across the response plots confirm the robustness of the developed design space and validate the effectiveness of the Quality by Design-based optimization approach in achieving predictable and reproducible nanosponge performance.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec43\" class=\"Section2\"\u003e \u003ch2\u003e3.5 Particle Size, Entrapment Efficiency and Drug Release\u003c/h2\u003e \u003cp\u003eParticle size analysis confirmed the formation of nanoscale Eltrombopag-loaded β-cyclodextrin nanosponges with a uniform size distribution in the optimized batch (F7). The nanoscale particle size is favorable for increasing surface area and improving wettability and dissolution behavior, thereby contributing to enhanced apparent solubility and controlled drug release.\u003c/p\u003e \u003cp\u003eEntrapment efficiency analysis demonstrated effective incorporation of Eltrombopag within the porous nanosponge matrix. The high entrapment efficiency observed for the optimized formulation indicates stable accommodation of the drug within the polymer network, which is essential for maintaining consistent drug content and ensuring reproducible release performance.\u003c/p\u003e \u003cp\u003eIn vitro drug release studies showed sustained and controlled release of Eltrombopag from the nanosponge formulation, with improved dissolution behavior compared to the pure drug. This release pattern can be attributed to diffusion-controlled release from the porous nanosponge architecture while preserving structural integrity during dissolution. Overall, these findings support the suitability of nanosponge carriers for enhancing the delivery performance of Eltrombopag.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab11\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 10\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eIn vitro drug release profile of Eltrombopag-loaded β-cyclodextrin nanosponges\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=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" 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=\"char\" char=\".\" 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\"\u003e \u003cp\u003eBatch\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 h\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2 h\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4 h\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6 h\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e8 h\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003e12 h\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e97\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e94\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e89\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e95\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e98\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e96\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e97\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e89\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e96\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e99\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e98\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eF9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e98\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\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec44\" class=\"Section2\"\u003e \u003ch2\u003e3.6 SEM Morphology Interpretation\u003c/h2\u003e \u003cp\u003eSEM micrographs of the optimized nanosponge formulation revealed discrete, porous, and nearly spherical particles with uniform surface morphology and minimal aggregation. The observed surface features confirm the successful formation of nanosponges, while SEM analysis primarily provides morphological information rather than quantitative drug distribution.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec45\" class=\"Section2\"\u003e \u003ch2\u003e3.7 Statistical Validation and Model Adequacy\u003c/h2\u003e \u003cp\u003eThe reliability and strength of the optimization model used in development of the formulations were statistically validated. The phase-solubility studies displayed a strong linear correlation, (R\u0026sup2; = 0.9998, p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001) thus supporting the predictive relationship between nanosponges concentration and enhancement of solubility. Analysis of one-way ANOVA demonstrated that the variables of formulation presented in the model had a statistically significant contribution to the model, with an extremely high F-value of 37235.12, which proves that the model is significant and the variability of the experiment is minimal. The release profile kinetic modelling suggested that the optimized formulation fits the Higuchi diffusion model (R\u0026sup2; = 0.987), which in turn validated diffusion-controlled drug release. The released exponent of the Korsmeyer-Peppas (n\u0026thinsp;=\u0026thinsp;0.61) indicated that it is related to anomalous transport that comprises diffusion as well as the polymer relaxation processes. The presence of high correlation coefficients and a consistent model fitting shows sufficient predictability as well as reliability of the model.\u003c/p\u003e \u003cp\u003eOverall, the statistical verification proves the adequacy, reproducibility, and strength of the nanosponges formulation to be adequate, reproducible, and robust. These statistical methods were incorporated, which also guaranteed the scientific credibility of the method and allowed the rational optimisation of the formulation parameters.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab12\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 11\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eConfirmatory batch validation results for optimized Eltrombopag nanosponge formulation\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\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=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePredicted\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eExperimental\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e% Error\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParticle Size (nm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e280\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e285\u0026thinsp;\u0026plusmn;\u0026thinsp;18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1.79\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEntrapment Efficiency (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e76.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e78.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.22\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDrug Release at 6 h (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e85.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e87.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.47\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eZeta Potential (mV)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026minus;30.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e\u0026minus;32.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e6.67\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"},{"header":"4. Conclusion","content":"\u003cp\u003eIn the present study, Eltrombopag-loaded β-cyclodextrin nanosponges were successfully developed and optimized using a Quality by Design approach. Preformulation and compatibility studies confirmed the physicochemical stability of Eltrombopag within the nanosponge system. The optimized formulation exhibited nanoscale particle size, high entrapment efficiency, and controlled drug release behavior.\u003c/p\u003e \u003cp\u003ePhase solubility and response surface analyses demonstrated a significant improvement in solubility and validated the robustness of the developed design space. The sustained and reproducible release profile observed for the optimized nanosponge formulation highlights the potential of nanosponge carriers to enhance the oral delivery performance of Eltrombopag. Overall, the findings support the applicability of QbD-guided nanosponge systems as a promising strategy for improving solubility and dissolution-limited drugs.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthors' Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAmol R. Pawar conducted the primary research work, including formulation development, Quality by Design optimization, data analysis, and manuscript drafting. Nidhi P. Shah provided technical input and assisted in data interpretation and manuscript review. Ujashkumar Shah supervised the study and contributed to critical revision and final approval of the manuscript. All authors approved the final version.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics Consent and Approval to Take Part\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study did not involve human participants or live animals. Therefore, ethical approval and informed consent were not required.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of Interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors do not have any conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of Data Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data created and/or processed in the course of the ongoing research can be obtained by the authorized writer on a case-by-case basis.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eGenerative AI and AI-Assisted Technologies in Writing\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDuring the preparation of this manuscript, artificial intelligence-based tools were used only to support linguistic refinement and formatting. The authors independently reviewed all scientific content, verified the accuracy of the data, and ensured the integrity of the analysis and conclusions.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eBussel JB, Cheng G, Saleh MN, et al. Eltrombopag for the treatment of chronic immune thrombocytopenic purpura. N Engl J Med. 2007; 357:2237-2247.\u003c/li\u003e\n\u003cli\u003eMcHutchison JW, Dusheiko EL, Shiffman M, et al. Eltrombopag for thrombocytopenia in patients with cirrhosis associated with hepatitis C. N Engl J Med. 357 (2007) 2227-2236.\u003c/li\u003e\n\u003cli\u003eMcDonald K, Fields S. Pharmacokinetics and clinical application of Eltrombopag. Clin Pharmacokinet. 51 (2012) 715-729.\u003c/li\u003e\n\u003cli\u003eKuter A. Biology and clinical application of thrombopoietin receptor agonists. Int J Hematol. 96 (2012) 707-719.\u003c/li\u003e\n\u003cli\u003eGhanima J, Bussel T. Eltrombopag: A review of safety and efficacy in thrombocytopenia. 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Trop J Pharm Res. 12 (2013) 255-264.\u003c/li\u003e\n\u003cli\u003eGoldstein L, Newbury DE, Echlin P, et al. Scanning electron microscopy and X-ray microanalysis. Springer, New York, 3rd Ed., 2003.\u003c/li\u003e\n\u003cli\u003eWagner JG. Interpretation of percent dissolved-time plots derived from in vitro testing of conventional tablets and capsules. J Pharm Sci. 58 (1969) 1253-1257.\u003c/li\u003e\n\u003cli\u003eMontgomery DC. Design and analysis of experiments. John Wiley \u0026amp; Sons, New York, 8th Ed., 2013.\u003c/li\u003e\n\u003cli\u003eSteel RG, Torrie JH. Principles and procedures of statistics: A biometrical approach. McGraw-Hill, New York, 3rd Ed., 1997.\u003c/li\u003e\n\u003cli\u003eTaguchi G, Chowdhury S, Taguchi S. Robust engineering: Learn how to boost quality while reducing costs and time to market. McGraw-Hill, New York, 2000.\u003c/li\u003e\n\u003cli\u003eAnderson DR, Sweeney DJ, Williams TA. Statistics for business and economics. Cengage Learning, Boston, 11th Ed., 2012.\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":"Cyclodextrin nanosponges, Quality by Design, Solubility enhancement, Oral drug delivery, Controlled drug release","lastPublishedDoi":"10.21203/rs.3.rs-8830792/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8830792/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eEltrombopag is an orally active thrombopoietin receptor agonist whose clinical performance is limited by poor aqueous solubility and variable gastrointestinal absorption caused by chelation with dietary cations. The present study was undertaken to develop and optimize β-cyclodextrin-based nanosponge carriers to improve the solubility, dissolution behavior, and oral delivery of Eltrombopag using a systematic Quality by Design (QbD) approach.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eβ-Cyclodextrin nanosponges loaded with Eltrombopag were prepared using different cross-linking agents and optimized through a Taguchi L9 experimental design. The effects of formulation and process variables on critical quality attributes, including particle size, drug entrapment efficiency, and in vitro drug release, were systematically investigated. The optimized formulation was characterized using Fourier-transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, dynamic light scattering, scanning electron microscopy, phase-solubility analysis, and in vitro dissolution studies.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe optimized nanosponge formulation demonstrated nanoscale particle size with narrow size distribution, high drug entrapment efficiency, and a marked improvement in dissolution behavior compared to the pure drug. Compatibility studies confirmed the absence of chemical interaction between Eltrombopag and formulation excipients, while morphological evaluation revealed a porous nanosponge architecture conducive to drug encapsulation. Phase-solubility analysis showed a linear enhancement in drug solubility, and in vitro dissolution studies indicated sustained and diffusion-controlled drug release. Stability studies confirmed acceptable physicochemical stability of the optimized formulation.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThe QbD-guided development of β-cyclodextrin nanosponges successfully improved the solubility and controlled release of Eltrombopag. This nanosponge-based delivery system offers a promising strategy for enhancing the oral bioavailability of dissolution-limited drugs and minimizing absorption variability associated with dietary interactions.\u003c/p\u003e","manuscriptTitle":"Design and Evaluation of β-Cyclodextrin Nanosponges for Enhanced Oral Delivery of Eltrombopag Using a Quality by Design Approach","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-10 13:02:42","doi":"10.21203/rs.3.rs-8830792/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":"2c03295f-1ee2-4057-84cc-136adbc2e54e","owner":[],"postedDate":"April 10th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-04-28T00:53:48+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-10 13:02:42","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8830792","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8830792","identity":"rs-8830792","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}