GMP compliant simplified fast and high yielding automated synthesis of [18F]Fallypride without the need of HPLC purification

GMP compliant simplified fast and high yielding automated synthesis of [18F]Fallypride without the need of HPLC purification | 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 GMP compliant simplified fast and high yielding automated synthesis of [18F]Fallypride without the need of HPLC purification Ammar Alfteimi, Yi Zhao, Ulf Lützen, Alexander Helm, Michael Jüptner, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6062704/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 04 May, 2025 Read the published version in EJNMMI Radiopharmacy and Chemistry → Version 1 posted 5 You are reading this latest preprint version Abstract Background [ 18 F]Fallypride PET has been used to study D2/3 receptor occupancy and density in neuropsychiatric disorders including Huntington’s disease (HD) and aging in humans. Nevertheless, the various synthetic methods including those provided by commercial synthesizers for [ 18 F]Fallypride exhibit a disadvantage concerning the necessity using a HPLC purification step, which causes difficulties in the automation, leads to long synthesis times and moderate yields. Therefore utilizing the purification step by SPE cartridges is considered highly desirable for future commercialization of radiopharmaceutical cassettes. In our lab we have developed a simplified reliable automatic radio synthesis of [ 18 F]Fallypride by using SPE cartridges for the purification step without the need of HPLC. Results A simplified radio synthesis of [ 18 F]Fallypride has been developed without the use of HPLC for both a commercial cassette based synthesis system (AllinOne (AiO) system, Trasis, Belgium) and a research synthesis module with fixed tubing (RNplus, Synthra, Germany). The cleaning step involves a serial combination of several SPE cartridges. The synthesis time was shortened by 44% compared to synthesis using HPLC. At the same time the not decay corrected yield increases from 44% to 59% by using TBAHCO 3 as phase transfer catalysts and from 17% to 31% for the synthesis with K 2 CO 3 /Kryptofix-[2.2.2] compared to synthesis using HPLC. The radio chemical purity was always >98% and all quality control parameters (e.g. sterility, endotoxin, stability and radio chemical purity) were conform to the European Pharmacopoeia. Conclusions A GMP compliant automatic synthesis of [ 18 F]Fallypride including purification using simple solid phase extraction cartridges instead of HPLC was developed and evaluated. The implementation of the simplified synthesis in both used commercial modules allows efficient and reproducible radio synthesis of [ 18 F]Fallypride and leads to short synthesis times and high radiochemical yields with high radiochemical purity. Automated radiosynthesis Fallypride D2/D3 receptors F-18 Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Background [ 18 F]Fallypride is a widely used positron emission tomographic (PET) radio tracer for imaging the dopaminergic system in the brain (Slifstein, et al., 2004 ; Honer, et al., 2004). It is a selective, high-affinity antagonist for D2/D3 receptors and has been employed to measure striatal and extrastriatal D2/D3 receptor. Its high specific in vivo uptake in brain regions containing DA D2/3 receptors as well as the reversibility of its in vivo binding to the receptors allows quantitation of their levels in striatal and extrastriatal brain regions using reversible kinetic modeling methods (Christian, et al., 2009 ; Mukherjee, et al., 1999 ; Constantinescu, et al., 2011 ; Siessmeier, et al., 2005). The first approach for the synthesis of [ 18 F]Fallypride was reported by Mukherjee and coworkers, performing manual synthesis (Mukherjee, et al., 1995 ). The radiochemical yields were between 20% and 40% (decay corrected) with 33–63 GBq/mmol of specific activity and relatively long reaction time of about 30 minutes. Moreover, a cleaning step had to be introduced, which takes up to additional 30 minutes. Later, a fully automated synthesis of [ 18 F]Fallypride by using the synthesizer TracerLab FX-FN (GE Healthcare) was proposed by Ansari et al (Ansari, et al., 2006). They could show that [ 18 F]Fallypride can be successfully carried out by one-step radiochemical synthesis with a tosylate precursor. The radiochemical yields were low (5–20%) and the synthesis time was 60 minutes. In this method also, considerable efforts were required to ensure the purification using high performance liquid chromatography (HPLC) causing long synthesis times and low yields. In 2008, the first automated synthesis of [ 18 F]Fallypride using only SPE purification was reported by Yang et al. (Yang, et al., 2008) with low radiochemical yield low of only 15%. Unfortunately, we were only able to find the abstract of this work containing very limited information on synthesis, purification method and quality control and therefore not sufficient to assess whether this method substantially complies with current good manufacturing practice (cGMP) guidelines. The highest yield (68% decay corrected) was reported two years later by Moon, et al. (Moon, et al., 2010 ). They carried out the synthesis by heating of 2 mg of tosyl-fallypride and [ 18 F]Fluoride in acetonitrile (1 mL) at 100 0 C for 10 min using 10 µL of 40% tetrabutylammoniumbicarbonate (TBAHCO 3 ) as a phase transfer catalyst with a total synthesis time of 51 min, including HPLC purification and solid-phase purification for the final formulation. The radiochemical purity was 97%. In all described cases, considerable efforts were required to ensure the purification using HPLC causing long synthesis times and low yields. Currently, the most synthesis module suppliers are moving from synthesizer with solid tubing to cassette systems. Single-use cassette-based systems allow the radiochemist to purchase pre-configured cassettes and software programs to avoid the intensive cleaning procedures, resulting in simplified operations and faster GMP compliance by eliminating the need for a validated cleaning method (Boschi, et al., 2013; Krasikova, et al., 2007). Another advantage of the cassette-based systems is that multiple syntheses can be easily performed even for various tracers and with different radionuclides by changing the cassette. At the same time, the use of cassettes provides improved microbiological safety and eliminates the risk of cross-contamination, thereby achieving better GMP compliance (Lepareur, 2022 ; Velikyan, 2015 ). A constraint of the synthesis of [ 18 F]Fallypride, even by using cassette-based platforms, is the continued need for HPLC equipment for the purification step. This causes radio syntheses to become more complex and increases the number of required steps. Therefore, the introduction of SPE cartridges for purification instead of HPLC is considered to be a way to improve radio synthesis and represents a desirable option to increase future commercialization of radiopharmaceutical cassettes. The aim of our study is to develop a GMP production of [ 18 F]Fallypride without HPLC purification step by using common commercial synthesizers. Methods & Materials Two commercially available synthesizers were used in this study. The first one is the Synthra RNplus research module with fixed tubing operated by the SynthraView software (Synthra, Hamburg, Germany) and the second is AllinOne synthesis module from Trasis with customized single use cassette operated by the software Trasis Supervision® (Trasis, Ans, Belgium). All single-use cassettes and reagent kits for the radio synthesis were sterile and manufactured under GMP conditions. The precursor (S)-N-[(1-allyl-2-pyrrolidinyl)methyl]-5-(3-toluenesulfonyloxypropyl)-2,3-dimethoxybenzamide (Tosyl-fallypride) and (S)-N-[(1-allyl-2-pyrrolidinyl)methyl]-5-(3-fluoropropyl)-2,3-dimethoxybenzamide (fallypride) were purchased from ABX (Radeberg; Germany). Sep Pak Light Alumina N Cartridges, Sep Pak Plus C18 Cartridges and Sep Pak Light C18 Cartridges were purchased from Waters (Eschborn, Germany). Other chemicals were purchased from commercial sources and were used without further purification. [ 18 F]Fluoride was produced via the 18 O(p,n) 18 F reaction with a CTI RDS 112 cyclotron (Berlin). Automated synthesis of [ 18 F]Fallypride using AllinOne Modul of Trasis For the fully automated synthesis of [ 18 F]Fallypride employing the Trasis AllinOne synthesizer, single-use cassettes for the synthesis of [ 18 F]-Choline supplied by Trasis (Trasis, Ans, Belgium) were used after modification. As usual with the AllinOne, the cassette was placed on the platform, the reagents loaded on it and the cartridges installed in the correct position as shown in the Fig. 1 . Automated synthesis of [F]Fallypride using RNplus Research module of Synthra The RNplus Research module from Synthra shown in Fig. 2 was used for the automated synthesis of [ 18 F]Fallypride. Prior to the synthesis, the module was cleaned by two automated methods. Firstly, washing with water to remove water-soluble contaminants from the peptide vial and the reaction vessel. Secondly, washing with an organic solvent (ethanol) to rinse all valves, the peptide vial and the reaction vessel. Finally, all module components were dried using nitrogen gas flow. Synthesis of [F]Fallypride using the phase transfer catalyst system KCO / Kryptofix-[2.2.2]: 20–25 GBq (n = 3, mean: 20.7 ± 4) [ 18 F]fluoride were delivered to the synthesis module (AllinOne or RNplus) as a solution in [ 18 O]H 2 O (1.8 mL). This solution was passed through a small anion exchange column (30 mg, HCO 3 -form) to trap the [ 18 F]fluoride. The [ 18 F]fluoride was then eluted into the reactor using a mixture of a solution of Kryptofix-[2.2.2] (15 mg in 0,8 mL acetonitrile) and a solution of aqueous potassium carbonate (200 µL, 0.1M). The solvent was then evaporated for 3 minutes at 70°C under vacuum with helium stream and further 3 minutes at 115°C followed by additional 3 min without helium flow under vacuum. The tosyl-Fallypride precursor (2mg) in acetonitrile (1ml) was then added to the dried [ 18 F]KF–K222 and the mixture was heated at 90°C for 20 minutes. Afterwards the reactor was cooled to 40°C. The reaction mixture was then passed through three cartridges connected in series: Alumina N Plus Light, Sep Pak Plus C18 and Sep Pak Light C18 cartridges. The cartridges were then washed with 40 mL of water. [ 18 F]Fallypride was eluted from the cartridges by 1 ml of ethanol, then passed through a 0.22 µm sterile filter and collected in the product vial before being further diluted with 12 ml of 0.9% aq. NaCl to obtain 6.8 ± 0.9Gbq (n = 3) of [ 18 F]Fallypride ready for human use in approximately 40 min (yield = 31 ± 3%, not decay corrected). The radiochemical purity was > 98%. Synthesis of [F]Fallypride using the phase transfer catalyst system TBAHCO: 2–5 GBq (n = 3, mean: 3.2 ± 1.4) [ 18 F]fluoride were delivered to the synthesis module (AllinOne or RNplus) as a solution in [ 18 O]H 2 O (1.8 mL). This solution was passed through a small anion exchange column (30 mg, HCO 3 - form) to trap the [ 18 F]fluoride. Then it was eluted to the reactor with a 10µL of 40% TBAHCO 3 in MeOH/H 2 O (1.0/0.2 mL). The eluate was evaporated to dryness in the reactor at 95°C within 6 minutes under vacuum and a stream of helium. Tosyl-Fallypride (2mg) in acetonitrile (1ml) were then added to the reactor and the mixture was heated at 95°C for 10 minutes. Afterwards the reactor was cooled to 40°C. The reaction mixture was then passed through three cartridges connected in series: Alumina N Plus Light, Sep Pak Plus C18 and Sep Pak Light C18 Cartridges. The cartridges were then washed with 40 mL of water. The [ 18 F]Fallypride was eluted from the cartridges by 1 ml of Ethanol, passed through a 0.22 µm sterile filter and collected in the product vial before being further diluted with 12 ml of 0.9% aq. NaCl to obtain 1.9 ± 0.Gbq (n = 3) of [ 18 F]Fallypride ready for human use in approximately 28 min (yield = 59 ± 4%, not decay corrected). The radiochemical purity was > 98%. [F]Fallypride Quality Control The quality control (QC) procedures performed for [ 18 F]Fallypride are based on the current requirements for radiopharmaceuticals set out in the European Pharmacopoeia for the manufacture of radiopharmaceuticals and the quality control release criteria and are summarized below. (Table 1 ). Table 1 Summary of the product specifications and validation results for three consecutive productions for [18F]Fallypride QC Test Release Criteria [ 18 F]Fallypride with TBA + (40%) (n = 3) [ 18 F]Fallypride with Kryptofix (n = 3) Yield % N/A 59% 31% Visual Inspection Clear, colorless Clear, colorless Clear, colorless Radiochemical Identity RRT = 0.9–1.1 1.01 1.01 Radiochemical Purity > 95% > 98,1 > 98,6 Residual Solvent Analysis Aceton < 5000 ppm - < 5000 ppm Ethanol No limit established ≤ 7,7% ≤ 7,7% Acetonitrile ≤ 410 ppm ≤ 410 ppm ≤ 410 ppm Dose pH 4.5–7.5 6.8 6.5 Residual Kryptofix ≤50 µg / mL TBA + ≤260 µg/mL ≤260 µg / mL ≤50 µg / mL Sterile Filter Integrity Test > 3,2 bar > 3,2 bar > 3,2 bar Radionuclidic Identity (t 1/2 ) 105–115 min 109 min 108 min Endotoxin Analysis ≤17.5 EU/mL < 5.0 EU/ml < 5.0 EU/ml Sterility Testing No colony growth out to 14 days passed passed Radio Chemical Identity and Purity HPLC analysis of the radiochemical identity was conducted using a System Gold HPLC System (Beckman Coulter, USA) fitted with an UV detector set to 265 nm and HERM LB 500 γ-detector (Berthold Technologies GmbH & Co. KG, Germany). The HPLC column was Chromolith HR RP-18 100x3 mm (Merck KGaA, Germany), Solvents: A: H 2 O (0.1% TFA); B: acetonitrile (0.1% TFA); gradient: 0–8 minutes 0-100%B; flow rate: 2.0 mL/min). The retention time of [ 18 F]Fallypride was compared to that of the [ 19 F]Fallypride reference standard (ABX GmbH, Germany). Representative analytical HPLC traces are displayed in Fig. 3 . TLC analysis The thin layer chromatography analysis (TLC) of the radiochemical purity was conducted using an Elysia-Raytest linear analyser detector RITA (Elysia-Raytest GmbH, Germany). Radio TLC was performed on Tec-Control Dark Green (Biodex Medical Systems, USA) developed with acetonitrile − 0.9% NaCl (1v/1v). Sterile filter integrity test: The sterile filter (with needle still attached) was connected to a nitrogen supply via a regulator. The needle was submerged in water and the nitrogen pressure was gradually increased. If the pressure was raised above the filter acceptance pressure (3.2 bars) without seeing a stream of bubbles, the filter was considered intact (Table 1 ). Dose pH The pH of a small amount of the [ 18 F]Fallypride solution was determined using Macherey-Nagel® pH 2.0–9.0 non-bleeding pH-indicator strips by visual comparison to the scale provided. As listed in Table 1 , the pH was ranging between 6.5 and 7.5. Endotoxin Analysis The endotoxin content in the synthesized [ 18 F]Fallypride was analyzed using a Endosafe® nexgen-PTS™ from Charles River. Doses had to contain ≤ 175 Endotoxin Units (EU) / mL to be deemed acceptable. Limulus-amoebocyte-lysate (LAL) test for bacterial endotoxin resulted < 17.5 EU/ml in all analyzed samples (Table 1 ). Sterility Testing Fluid thioglycolate media (FTM) plates and soybean casein digest agar media (SCDM) plates were treated with samples of [ 18 F]Fallypride. FTM plates were used to test for anaerobes, aerobes and micro aerophiles whilst SCDM plates were used to test for non-fastidious and fastidious microorganisms. [ 18 F]Fallypride-treated plates were incubated with positive and negative controls for 14 days. FTM plates were incubated at 32°C and SCDM plates were incubated at 22°C according to the European Pharmacopoeia (Ph. Eur.). Plates were visually inspected on the 3rd, the 8th and the 14th day of the test and compared to the positive and negative standards. Positive standards had to show growth (turbidity) on the plates and [ 18 F]Fallypride negative controls had to have no culture growth after 14 days to be indicative of sterility. All samples met the sterility specifications (Table 1 ). Thin layer chromatography spot test for determination of kryptofix-[2.2.2] and TBAHCO 3 content The Kryptofix-[2.2.2] content was determined by using the thin layer chromatography technique on POLYGRAM® SIL G / UV254, 4 x 8 cm plate using a mixture of methanol and 25% ammonium hydroxide solution in water (90:10 v / v) as the mobile phase. Spots of 1,0 µL of standard solution of Kryptofix-[2.2.2] or TBAHCO 3 in the concentration of 50 µg/mL, sample of [ 18 F]Fallypride, solvent (water: EtOH: 9:1) and positive control (500 µg/mL) were applied established 1 cm from the lower edge of the chromatographic sheet by means of an Eppendorf micro pipette. The samples were then dried with the aid of a hot air blower. The sheet was developed with the mobile phase and the dried sheets were then placed on a holder inside a glass chamber homogenously saturated with iodine vapor (ca. 5 gr) for 1 minute. Any spot had not to be more intense than the reference solution, consequently containing only an equal or lower than 50 µg/mL of Kryptofix-[2.2.2] or TBAHCO 3 to meet Ph. Eur. requirements for the limit of Kryptofix-[2.2.2] impurities in 18 F-labelled radiopharmaceuticals. RESULTS An improved GMP compliant synthesis method for [ 18 F]Fallypride has been developed for both the cassette based synthesis system AllinOne (AiO) and the research synthesis module with fixed tubing (RNplus). [ 18 F]Fallypride could be obtained ready for human use as physiological solution after purification on Alumina N Plus Light, Sep Pak Plus C18 and Sep Pak Light C18 cartridges and formulation with 1ml ethanol. The Radiochemical purity was > 98% and no contamination of the sterile solution with chemicals or solvents used during the synthesis was detected (Table 1 ). Representative chromatograms of radio HPLC and radio TLC are presented in Figs. 3 and 4 b. Repeated analyzes up to 4 h after synthesis showed that the radiochemical purity was still > 95%.The method involves the abandonment of HPLC purification in favor of a faster and more convenient SPE purification method that led to [ 18 F]Fallypride as physiological solution ready for human use meeting all required specifications for radiopharmaceuticals. For both synthesizers (AiO and RNplus) the optimization of the synthesis parameters in combination with the SPE cartridge purification results in [ 18 F]Fallypride in high radiochemical yield (59% not decay corrected) in only 28 minutes when using TBAHCO 3 as phase transfer catalyst system and 31% (not decay corrected) in 40 minutes when using K 2 CO 3 / Kryptofix-[2.2.2] (Table 1 ). The studies on the effect of the reaction temperature (Fig. 5 ), precursor amount (Fig. 6 ) and reaction time (Fig. 7 ) show that the maximum radiochemical yield is reached at 95°, with 2 mg precursor and 10 minutes reaction time. DISCUSSION In recent decades there has been a shift in the field of automated synthesis modules for radiopharmaceuticals from the fixed tubing system, in which the liquid flow is regulated by inert gas, to a sterile disposable cassette system, in which the liquid flow is regulated by a syringe pump. One of the key advantages of the cassette system approach is that it provides greater microbiological safety and eliminates the risk of cross-contamination compared to the fixed tube approach. In this way, the GMP requirements are met better. However, cassette systems also have some disadvantages compared to fixed tubing systems. The main disadvantage of using disposable cassettes is their high cost and the dependency on the cassette manufacturers. Though, for both systems, in many cases, purification of the product using HPLC is necessary, which means additional complications and long synthesis times. In these cases, the possibility of using SPE cartridges instead of HPLC is highly desirable as it significantly simplifies the synthesis and increases flexibility. In a previous work by Moon et al. from 2010 the radio synthesis of [ 18 F]Fallypride was carried out by a labeling reaction using the phase transfer catalyst TBAHCO 3 (Moon, et al., 2010 ). They reported maximum radiochemical yield of approximately 45% (not decay corrected) at 100°C and a reaction duration of 51 minutes. Due to the need to use HPLC for the purification of the final product, this method is quite complex and needs long syntheses time. This circumstance may limit the application of [ 18 F]Fallypride in clinical practice and leads to relatively high dose cost rate. For this reason, we turned our attention to develop a simplified fast and high yielding automated synthesis using appropriate cartridges for the purification instead of an HPLC run. Using the Synthra RNplus research module with fixed tubing, we started with the synthesis of [ 18 F]Fallypride described by Moon et al. (Moon, et al., 2010 ) and replaced the HPLC purification by a Sep-Pak plus C-18 cartridge purification as described by Yang et al. (Yang, et al., 2008). However We found out that the recovery of [ 18 F]Fallypride was only 85%. Accordingly, 15% of the product was not retained by the cartridge and was lost as it was eluted through the Sep-Pak plus C-18 cartridge into the waste. In addition, the determined radiochemical purity using radio TLC analysis reveals a radiochemical purity of only ~ 94% [ 18 F]Fallypride (Fig. 4 a). For this reason, we introduced two modifications to the purification process. Firstly, we added a Sep-Pak Alumina-N cartridge as this was suggested to eliminate the non-reacted [ 18 F]fluoride (Shao, et al., 2011 ) and secondly, we added a second Sep Pak Light C18 cartridge to increase the trapping efficiency of [ 18 F]Fallypride and minimize its loss of into the waste. In this way the loss of [ 18 F]Fallypride into the waste was reduced to 98%. (Figs. 3 and 4 b) Next, we focused on optimizing the labelling conditions to increase the radiochemical yield and to reduce the reaction time by optimizing the reaction temperature. We carried out two series of syntheses under different reaction temperatures using both the phase transfer catalysts systems TBAHCO 3 and K 2 CO 3 /Kryptofix-[2.2.2]. The results are shown in Fig. 5 and show an optimal reaction temperature of about 95°C. The influence of precursor amounts on yields was then subsequently studied with five different precursor amounts of 1mg, 2mg, 2,5mg, 3mg, 4mg and 5mg at a reaction temperature of 95°C. The results are represented in Fig. 6 . The maximum yield of [ 18 F]Fallypride was achieved when using 2 mg of precursor. The radiochemical purity was higher than 98% as shown in a representative HPLC- and TLC-radio chromatogram in Figs. 3 and 4 b. This chromatogram shows a main peak corresponding to [ 18 F]Fallypride with a retention time of 4.25 min accompanied by a small shoulder after this main peak. This poorly separated shoulder, which is probably caused by radiolysis, increased to about 3% of the total radioactivity when more than 3 mg of precursor was used. For this reason, the amount of precursor should not exceed 2 mg. Applying the already found best conditions for the reaction temperature and precursor amounts (95°C with TBAHCO 3 ; 90°C with K 2 CO 3 /Kryptofix-[2.2.2]; 2 mg precursor) the effect of the reaction time was then examined. The experiments showed an optimal reaction time of 10 minutes with TBAHCO 3 and 20 min with K 2 CO 3 /Kryptofix-[2.2.2] (Fig. 7 ). Since GMP regulations for radiopharmaceuticals tend to support single-use cassette systems, cartridge cleaning instead of HPLC cleaning in these systems simplifies operations and facilitates GMP compliance. In addition, the use of synthesizers with disposable cassettes increases reliability and enables rapid training of production personnel. Therefore, we transferred the conditions for the [ 18 F]Fallypride synthesis obtained with the Synthra RNplus Research module to the AllinOne module from Trasis. The [ 18 F]Fallypride synthesis with the AllinOne module applying these conditions and using the parameters as shown in Fig. 1 gave the same results as with the RNplus Research module. Conclusion We could successfully demonstrate that the synthesis of [ 18 F]Fallypride is practicable on commercial cassette-based systems as well as on customized modules with fixed tubing systems without the need for HPLC purification. The fully automated protocols are in accordance to GMP standards and allow the synthesis of [ 18 F]Fallypride without HPLC within 28 min including purification and formulation steps with high labeling yield as well as high radio chemical and radionuclide purity. Abbreviations GMP good manufacturing practice HPLC high performance liquid chromatography PET positron emission tomography Ph Eur European pharmacopeia QC Quality control TLC thin-layer chromatography Declarations Acknowledgement Not Applicable. Funding Not Applicable. Author information Affiliations Department of Nuclear Medicine, Molecular Diagnostic Imaging and Therapy, University Hospital of Schleswig-Holstein (UKSH), Karl Lennert Cancer Center North, D-24105 Kiel, Germany Ammar Alfteimi*, Yi Zhao*, Ulf Lützen, Alexander Helm, Michael Jüptner, Maaz Zuhayra Contributions MZ: Conception and design of the work and oversaw the research project and approved the final manuscript. AA*: performed the chemistry and radiochemistry experiments and analyzed the results. YZ*, UL, AH and MJ contributed in writing and revising the manuscript and interpretation of the data. All authors read and approved the final manuscript. *: Both authors contributed equally to this manuscript Corresponding author: Prof. Dr. Maaz Zuhayra Ethics declarations Ethical approval and consent to participate This work does not contain any clinical study. Consent for publication Not applicable. Competing interests No competing interests. Availability of data and materials All data generated or analyzed during this study are included in this published article. References Ansari, M., Kessler, R., Clanton, J., Paulis, T. D., & Baldwin, R. (2006, May 1). Comparison of three [18f]Fallypride methods intended for automated remote chemistry modules. Journal of Nuclear Medicine. https://jnm.snmjournals.org/content/47/suppl_1/159P.1 Boschi, S., Lodi, F., Malizia, C., Cicoria, G., & Marengo, M. (2013a). 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Journal of Labelled Compounds and Radiopharmaceuticals , 54 (6), 292–307. https://doi.org/10.1002/jlcr.1865 Siessmeier, T., Zhou, Y., Buchholz, H.-G., Landvogt, C., Vernaleken, I., Piel, M., Schirrmacher, R., Rösch, F., Schreckenberger, M., Wong, D. F., Cumming, P., Gründer, G., & Bartenstein, P. (2005, June 1). Parametric mapping of binding in human brain of D2 receptor ligands of different affinities. Journal of Nuclear Medicine. https://jnm.snmjournals.org/content/46/6/964/tab-article-info Slifstein, M., Hwang, D.-R., Huang, Y., Guo, N., Sudo, Y., Narendran, R., Talbot, P., & Laruelle, M. (2004). In vivo affinity of [18F]Fallypride for striatal and extrastriatal dopamine D2 receptors in nonhuman primates. Psychopharmacology, 175(3), 274–286. https://doi.org/10.1007/s00213-004-1830-x Velikyan, I. (2015). 68ga-based radiopharmaceuticals: Production and application relationship. Molecules, 20(7), 12913–12943. https://doi.org/10.3390/molecules200712913 Yang, M., Xu, Y., Pan, D., & Luo, S. (2008, May 1). Simplified radiosynthesis of 18F-Fallypride. Journal of Nuclear Medicine. https://jnm.snmjournals.org/content/49/supplement_1/307P.1 Cite Share Download PDF Status: Published Journal Publication published 04 May, 2025 Read the published version in EJNMMI Radiopharmacy and Chemistry → Version 1 posted Editorial decision: Major revision 17 Mar, 2025 Reviewers agreed at journal 27 Feb, 2025 Reviewers invited by journal 27 Feb, 2025 Editor assigned by journal 26 Feb, 2025 First submitted to journal 25 Feb, 2025 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. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6062704","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":421763512,"identity":"72324895-2bd0-4bbb-8055-a5be365d9479","order_by":0,"name":"Ammar Alfteimi","email":"","orcid":"","institution":"Universitätsklinikum Schleswig-Holstein: Universitatsklinikum Schleswig-Holstein","correspondingAuthor":false,"prefix":"","firstName":"Ammar","middleName":"","lastName":"Alfteimi","suffix":""},{"id":421763513,"identity":"b351068c-c496-4eeb-b28c-b2e240ee9ffb","order_by":1,"name":"Yi Zhao","email":"","orcid":"","institution":"University Hospital Schleswig Holstein: Universitatsklinikum Schleswig-Holstein","correspondingAuthor":false,"prefix":"","firstName":"Yi","middleName":"","lastName":"Zhao","suffix":""},{"id":421763514,"identity":"524bebfb-2686-4a3e-809b-885ed10d455a","order_by":2,"name":"Ulf Lützen","email":"","orcid":"","institution":"University Hospital Schleswig Holstein: Universitatsklinikum Schleswig-Holstein","correspondingAuthor":false,"prefix":"","firstName":"Ulf","middleName":"","lastName":"Lützen","suffix":""},{"id":421763515,"identity":"2b4a9041-4c2e-462d-a1a8-f48f30dd6a4d","order_by":3,"name":"Alexander Helm","email":"","orcid":"","institution":"University Hospital Schleswig Holstein: Universitatsklinikum Schleswig-Holstein","correspondingAuthor":false,"prefix":"","firstName":"Alexander","middleName":"","lastName":"Helm","suffix":""},{"id":421763516,"identity":"f1c5ca9f-b7ad-45d4-926f-7ec832ce7668","order_by":4,"name":"Michael Jüptner","email":"","orcid":"","institution":"University Hospital Schleswig Holstein: Universitatsklinikum Schleswig-Holstein","correspondingAuthor":false,"prefix":"","firstName":"Michael","middleName":"","lastName":"Jüptner","suffix":""},{"id":421763517,"identity":"b235d7ed-cb4a-47f7-9433-9c570b7070ff","order_by":5,"name":"Maaz Zuhayra","email":"data:image/png;base64,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","orcid":"","institution":"Universitätsklinikum Schleswig-Holstein: Universitatsklinikum Schleswig-Holstein","correspondingAuthor":true,"prefix":"","firstName":"Maaz","middleName":"","lastName":"Zuhayra","suffix":""}],"badges":[],"createdAt":"2025-02-19 09:35:38","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6062704/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6062704/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s41181-025-00343-w","type":"published","date":"2025-05-04T15:57:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":77747796,"identity":"cbac0981-5e2d-4699-a479-6a4340392f19","added_by":"auto","created_at":"2025-03-05 07:00:43","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":50634,"visible":true,"origin":"","legend":"\u003cp\u003eScheme of the automated synthesizer of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride using AllinOne synthesis module\u003c/p\u003e","description":"","filename":"1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6062704/v1/24c5289648c5b9634f56994c.jpg"},{"id":77746603,"identity":"e86a0625-88c0-4aef-9520-48ba58ccfccf","added_by":"auto","created_at":"2025-03-05 06:44:43","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":101120,"visible":true,"origin":"","legend":"\u003cp\u003eScheme of the automated synthesizer of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride using Synthra RNplus Research module\u003c/p\u003e","description":"","filename":"2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6062704/v1/bc563aa7655a9620325d1d72.jpg"},{"id":77748503,"identity":"19743097-f73d-4766-ab44-e389842942cc","added_by":"auto","created_at":"2025-03-05 07:08:52","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":34737,"visible":true,"origin":"","legend":"\u003cp\u003eRadiochemical purity detection of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride analized via HPLC with UV detector at 220 nm and radioactivity detector (NaI)\u003c/p\u003e","description":"","filename":"3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6062704/v1/2ba33b5f7f0d37d077890b1a.jpg"},{"id":77746606,"identity":"dde7640f-66c1-4783-904a-552e123ed489","added_by":"auto","created_at":"2025-03-05 06:44:43","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":97458,"visible":true,"origin":"","legend":"\u003cp\u003eRadiochemical purity analyzed with radio TLC scanner\u003c/p\u003e\n\u003cp\u003eA: for [\u003csup\u003e18\u003c/sup\u003eF]Fallypride purified using only a Sep-Pak plus C-18 cartridge\u003c/p\u003e\n\u003cp\u003eB: the same as A, but with addition of a Sep-Pak Alumina-N cartridge and Sep Pak Light C18 Cartridge.\u003c/p\u003e","description":"","filename":"4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6062704/v1/aa05362e52a15183c2cfff14.jpg"},{"id":77746877,"identity":"b3e16b47-e13f-423e-a98a-034917e8ff0c","added_by":"auto","created_at":"2025-03-05 06:52:43","extension":"jpg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":35947,"visible":true,"origin":"","legend":"\u003cp\u003eRadiochemical yield of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride at versus temperature using 2mg precursor and 10 minutes reaction time with TBAHCO\u003csub\u003e3\u003c/sub\u003e as well as 20 minutes reaction time with K\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e/Kryptofix-[2.2.2].\u003c/p\u003e","description":"","filename":"5.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6062704/v1/83962843bc7cd7f5d2e4d8ac.jpg"},{"id":77746872,"identity":"925eea3f-7b79-454c-921e-9698e7474ab2","added_by":"auto","created_at":"2025-03-05 06:52:43","extension":"jpg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":41213,"visible":true,"origin":"","legend":"\u003cp\u003eDependence of the radiochemical yield of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride on the quantity of precursor for 10 minutes reaction time with TBAHCO\u003csub\u003e3\u003c/sub\u003e and 20 min with K\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e/Kryptofix-[2.2.2] at reaction time 95°C.\u003c/p\u003e","description":"","filename":"6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6062704/v1/8a258ca4ed03814a8ec197ca.jpg"},{"id":77746878,"identity":"e5f027a3-b0d0-45f3-b8f9-07758d5a1751","added_by":"auto","created_at":"2025-03-05 06:52:43","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":34671,"visible":true,"origin":"","legend":"\u003cp\u003eDependence of the radiochemical yield of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride on reaction time using 2 mg of precursor at 95°C.\u003c/p\u003e","description":"","filename":"7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6062704/v1/43338e1d5c22b2f6075ba39c.jpg"},{"id":81987827,"identity":"aaa58cb1-df65-407c-8cee-b66b9991761d","added_by":"auto","created_at":"2025-05-05 16:06:24","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1175837,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6062704/v1/34ad1582-0acc-43b5-80a5-d0e2474cfee6.pdf"}],"financialInterests":"","formattedTitle":"GMP compliant simplified fast and high yielding automated synthesis of [18F]Fallypride without the need of HPLC purification","fulltext":[{"header":"Background","content":"\u003cp\u003e[\u003csup\u003e18\u003c/sup\u003eF]Fallypride is a widely used positron emission tomographic (PET) radio tracer for imaging the dopaminergic system in the brain (Slifstein, et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Honer, et al., 2004). It is a selective, high-affinity antagonist for D2/D3 receptors and has been employed to measure striatal and extrastriatal D2/D3 receptor. Its high specific in vivo uptake in brain regions containing DA D2/3 receptors as well as the reversibility of its in vivo binding to the receptors allows quantitation of their levels in striatal and extrastriatal brain regions using reversible kinetic modeling methods (Christian, et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Mukherjee, et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; Constantinescu, et al., \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Siessmeier, et al., 2005).\u003c/p\u003e \u003cp\u003eThe first approach for the synthesis of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride was reported by Mukherjee and coworkers, performing manual synthesis (Mukherjee, et al., \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1995\u003c/span\u003e). The radiochemical yields were between 20% and 40% (decay corrected) with 33\u0026ndash;63 GBq/mmol of specific activity and relatively long reaction time of about 30 minutes. Moreover, a cleaning step had to be introduced, which takes up to additional 30 minutes. Later, a fully automated synthesis of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride by using the synthesizer TracerLab FX-FN (GE Healthcare) was proposed by Ansari et al (Ansari, et al., 2006). They could show that [\u003csup\u003e18\u003c/sup\u003eF]Fallypride can be successfully carried out by one-step radiochemical synthesis with a tosylate precursor. The radiochemical yields were low (5\u0026ndash;20%) and the synthesis time was 60 minutes. In this method also, considerable efforts were required to ensure the purification using high performance liquid chromatography (HPLC) causing long synthesis times and low yields. In 2008, the first automated synthesis of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride using only SPE purification was reported by Yang et al. (Yang, et al., 2008) with low radiochemical yield low of only 15%. Unfortunately, we were only able to find the abstract of this work containing very limited information on synthesis, purification method and quality control and therefore not sufficient to assess whether this method substantially complies with current good manufacturing practice (cGMP) guidelines.\u003c/p\u003e \u003cp\u003eThe highest yield (68% decay corrected) was reported two years later by Moon, et al. (Moon, et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). They carried out the synthesis by heating of 2 mg of tosyl-fallypride and [\u003csup\u003e18\u003c/sup\u003eF]Fluoride in acetonitrile (1 mL) at 100 \u003csup\u003e0\u003c/sup\u003eC for 10 min using 10 \u0026micro;L of 40% tetrabutylammoniumbicarbonate (TBAHCO\u003csub\u003e3\u003c/sub\u003e) as a phase transfer catalyst with a total synthesis time of 51 min, including HPLC purification and solid-phase purification for the final formulation. The radiochemical purity was 97%. In all described cases, considerable efforts were required to ensure the purification using HPLC causing long synthesis times and low yields.\u003c/p\u003e \u003cp\u003eCurrently, the most synthesis module suppliers are moving from synthesizer with solid tubing to cassette systems. Single-use cassette-based systems allow the radiochemist to purchase pre-configured cassettes and software programs to avoid the intensive cleaning procedures, resulting in simplified operations and faster GMP compliance by eliminating the need for a validated cleaning method (Boschi, et al., 2013; Krasikova, et al., 2007). Another advantage of the cassette-based systems is that multiple syntheses can be easily performed even for various tracers and with different radionuclides by changing the cassette. At the same time, the use of cassettes provides improved microbiological safety and eliminates the risk of cross-contamination, thereby achieving better GMP compliance (Lepareur, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Velikyan, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2015\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eA constraint of the synthesis of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride, even by using cassette-based platforms, is the continued need for HPLC equipment for the purification step. This causes radio syntheses to become more complex and increases the number of required steps. Therefore, the introduction of SPE cartridges for purification instead of HPLC is considered to be a way to improve radio synthesis and represents a desirable option to increase future commercialization of radiopharmaceutical cassettes. The aim of our study is to develop a GMP production of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride without HPLC purification step by using common commercial synthesizers.\u003c/p\u003e"},{"header":"Methods \u0026 Materials","content":"\u003cp\u003eTwo commercially available synthesizers were used in this study. The first one is the Synthra RNplus research module with fixed tubing operated by the SynthraView software (Synthra, Hamburg, Germany) and the second is AllinOne synthesis module from Trasis with customized single use cassette operated by the software Trasis Supervision\u0026reg; (Trasis, Ans, Belgium). All single-use cassettes and reagent kits for the radio synthesis were sterile and manufactured under GMP conditions.\u003c/p\u003e \u003cp\u003eThe precursor (S)-N-[(1-allyl-2-pyrrolidinyl)methyl]-5-(3-toluenesulfonyloxypropyl)-2,3-dimethoxybenzamide (Tosyl-fallypride) and (S)-N-[(1-allyl-2-pyrrolidinyl)methyl]-5-(3-fluoropropyl)-2,3-dimethoxybenzamide (fallypride) were purchased from ABX (Radeberg; Germany). Sep Pak Light Alumina N Cartridges, Sep Pak Plus C18 Cartridges and Sep Pak Light C18 Cartridges were purchased from Waters (Eschborn, Germany). Other chemicals were purchased from commercial sources and were used without further purification. [\u003csup\u003e18\u003c/sup\u003eF]Fluoride was produced via the \u003csup\u003e18\u003c/sup\u003eO(p,n)\u003csup\u003e18\u003c/sup\u003eF reaction with a CTI RDS 112 cyclotron (Berlin).\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eAutomated synthesis of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride using AllinOne Modul of Trasis\u003c/h2\u003e \u003cp\u003eFor the fully automated synthesis of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride employing the Trasis AllinOne synthesizer, single-use cassettes for the synthesis of [\u003csup\u003e18\u003c/sup\u003eF]-Choline supplied by Trasis (Trasis, Ans, Belgium) were used after modification. As usual with the AllinOne, the cassette was placed on the platform, the reagents loaded on it and the cartridges installed in the correct position as shown in the Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eAutomated synthesis of [F]Fallypride using RNplus Research module of Synthra\u003c/h3\u003e\n\u003cp\u003eThe RNplus Research module from Synthra shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e was used for the automated synthesis of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride. Prior to the synthesis, the module was cleaned by two automated methods. Firstly, washing with water to remove water-soluble contaminants from the peptide vial and the reaction vessel. Secondly, washing with an organic solvent (ethanol) to rinse all valves, the peptide vial and the reaction vessel. Finally, all module components were dried using nitrogen gas flow.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eSynthesis of [F]Fallypride using the phase transfer catalyst system KCO / Kryptofix-[2.2.2]:\u003c/h3\u003e\n\u003cp\u003e20\u0026ndash;25 GBq (n\u0026thinsp;=\u0026thinsp;3, mean: 20.7\u0026thinsp;\u0026plusmn;\u0026thinsp;4) [\u003csup\u003e18\u003c/sup\u003eF]fluoride were delivered to the synthesis module (AllinOne or RNplus) as a solution in [\u003csup\u003e18\u003c/sup\u003eO]H\u003csub\u003e2\u003c/sub\u003eO (1.8 mL). This solution was passed through a small anion exchange column (30 mg, HCO\u003csub\u003e3\u003c/sub\u003e-form) to trap the [\u003csup\u003e18\u003c/sup\u003eF]fluoride. The [\u003csup\u003e18\u003c/sup\u003eF]fluoride was then eluted into the reactor using a mixture of a solution of Kryptofix-[2.2.2] (15 mg in 0,8 mL acetonitrile) and a solution of aqueous potassium carbonate (200 \u0026micro;L, 0.1M). The solvent was then evaporated for 3 minutes at 70\u0026deg;C under vacuum with helium stream and further 3 minutes at 115\u0026deg;C followed by additional 3 min without helium flow under vacuum. The tosyl-Fallypride precursor (2mg) in acetonitrile (1ml) was then added to the dried [\u003csup\u003e18\u003c/sup\u003eF]KF\u0026ndash;K222 and the mixture was heated at 90\u0026deg;C for 20 minutes. Afterwards the reactor was cooled to 40\u0026deg;C. The reaction mixture was then passed through three cartridges connected in series: Alumina N Plus Light, Sep Pak Plus C18 and Sep Pak Light C18 cartridges. The cartridges were then washed with 40 mL of water. [\u003csup\u003e18\u003c/sup\u003eF]Fallypride was eluted from the cartridges by 1 ml of ethanol, then passed through a 0.22 \u0026micro;m sterile filter and collected in the product vial before being further diluted with 12 ml of 0.9% aq. NaCl to obtain 6.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9Gbq (n\u0026thinsp;=\u0026thinsp;3) of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride ready for human use in approximately 40 min (yield\u0026thinsp;=\u0026thinsp;31\u0026thinsp;\u0026plusmn;\u0026thinsp;3%, not decay corrected). The radiochemical purity was \u0026gt;\u0026thinsp;98%.\u003c/p\u003e\n\u003ch3\u003eSynthesis of [F]Fallypride using the phase transfer catalyst system TBAHCO:\u003c/h3\u003e\n\u003cp\u003e2\u0026ndash;5 GBq (n\u0026thinsp;=\u0026thinsp;3, mean: 3.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.4) [\u003csup\u003e18\u003c/sup\u003eF]fluoride were delivered to the synthesis module (AllinOne or RNplus) as a solution in [\u003csup\u003e18\u003c/sup\u003eO]H\u003csub\u003e2\u003c/sub\u003eO (1.8 mL). This solution was passed through a small anion exchange column (30 mg, HCO\u003csub\u003e3\u003c/sub\u003e\u003csup\u003e-\u003c/sup\u003eform) to trap the [\u003csup\u003e18\u003c/sup\u003eF]fluoride. Then it was eluted to the reactor with a 10\u0026micro;L of 40% TBAHCO\u003csub\u003e3\u003c/sub\u003e in MeOH/H\u003csub\u003e2\u003c/sub\u003eO (1.0/0.2 mL). The eluate was evaporated to dryness in the reactor at 95\u0026deg;C within 6 minutes under vacuum and a stream of helium.\u003c/p\u003e \u003cp\u003eTosyl-Fallypride (2mg) in acetonitrile (1ml) were then added to the reactor and the mixture was heated at 95\u0026deg;C for 10 minutes. Afterwards the reactor was cooled to 40\u0026deg;C. The reaction mixture was then passed through three cartridges connected in series: Alumina N Plus Light, Sep Pak Plus C18 and Sep Pak Light C18 Cartridges. The cartridges were then washed with 40 mL of water. The [\u003csup\u003e18\u003c/sup\u003eF]Fallypride was eluted from the cartridges by 1 ml of Ethanol, passed through a 0.22 \u0026micro;m sterile filter and collected in the product vial before being further diluted with 12 ml of 0.9% aq. NaCl to obtain 1.9\u0026thinsp;\u0026plusmn;\u0026thinsp;0.Gbq (n\u0026thinsp;=\u0026thinsp;3) of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride ready for human use in approximately 28 min (yield\u0026thinsp;=\u0026thinsp;59\u0026thinsp;\u0026plusmn;\u0026thinsp;4%, not decay corrected). The radiochemical purity was \u0026gt;\u0026thinsp;98%.\u003c/p\u003e\n\u003ch3\u003e[F]Fallypride Quality Control\u003c/h3\u003e\n\u003cp\u003eThe quality control (QC) procedures performed for [\u003csup\u003e18\u003c/sup\u003eF]Fallypride are based on the current requirements for radiopharmaceuticals set out in the European Pharmacopoeia for the manufacture of radiopharmaceuticals and the quality control release criteria and are summarized below. (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\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\u003c/div\u003e\u003cdiv\u003eSummary of the product specifications and validation results for three consecutive productions for [18F]Fallypride \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=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQC Test\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRelease Criteria\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e[\u003csup\u003e18\u003c/sup\u003eF]Fallypride with TBA\u003csup\u003e+\u003c/sup\u003e(40%)\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;3)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e[\u003csup\u003e18\u003c/sup\u003eF]Fallypride with Kryptofix\u003c/p\u003e \u003cp\u003e(n\u0026thinsp;=\u0026thinsp;3)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eYield %\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e59%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e31%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVisual Inspection\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eClear, colorless\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eClear, colorless\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eClear, colorless\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRadiochemical Identity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRRT\u0026thinsp;=\u0026thinsp;0.9\u0026ndash;1.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.01\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRadiochemical Purity\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;95%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;98,1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;98,6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e \u003cp\u003eResidual Solvent\u003c/p\u003e \u003cp\u003eAnalysis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAceton\u003c/p\u003e \u003cp\u003e\u0026lt;\u0026thinsp;5000 ppm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;5000 ppm\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEthanol\u003c/p\u003e \u003cp\u003eNo limit established\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026le; 7,7%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026le; 7,7%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAcetonitrile\u003c/p\u003e \u003cp\u003e\u0026le;\u0026thinsp;410 ppm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026le;\u0026thinsp;410 ppm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026le;\u0026thinsp;410 ppm\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDose pH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.5\u0026ndash;7.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eResidual\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eKryptofix \u0026le;50 \u0026micro;g / mL\u003c/p\u003e \u003cp\u003eTBA\u003csup\u003e+\u003c/sup\u003e\u0026le;260 \u0026micro;g/mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026le;260 \u0026micro;g / mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026le;50 \u0026micro;g / mL\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSterile Filter\u003c/p\u003e \u003cp\u003eIntegrity Test\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;3,2 bar\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;3,2 bar\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;3,2 bar\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRadionuclidic Identity (t\u003csub\u003e1/2\u003c/sub\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e105\u0026ndash;115 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e109 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e108 min\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEndotoxin Analysis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026le;17.5 EU/mL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;5.0 EU/ml\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;5.0 EU/ml\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSterility Testing\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNo colony growth out to 14 days\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003epassed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003epassed\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=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eRadio Chemical Identity and Purity\u003c/h2\u003e \u003cp\u003eHPLC analysis of the radiochemical identity was conducted using a System Gold HPLC System (Beckman Coulter, USA) fitted with an UV detector set to 265 nm and HERM LB 500 γ-detector (Berthold Technologies GmbH \u0026amp; Co. KG, Germany). The HPLC column was Chromolith HR RP-18 100x3 mm (Merck KGaA, Germany), Solvents: A: H\u003csub\u003e2\u003c/sub\u003eO (0.1% TFA); B: acetonitrile (0.1% TFA); gradient: 0\u0026ndash;8 minutes 0-100%B; flow rate: 2.0 mL/min).\u003c/p\u003e \u003cp\u003eThe retention time of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride was compared to that of the [\u003csup\u003e19\u003c/sup\u003eF]Fallypride reference standard (ABX GmbH, Germany). Representative analytical HPLC traces are displayed in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eTLC analysis\u003c/h3\u003e\n\u003cp\u003eThe thin layer chromatography analysis (TLC) of the radiochemical purity was conducted using an Elysia-Raytest linear analyser detector RITA (Elysia-Raytest GmbH, Germany). Radio TLC was performed on Tec-Control Dark Green (Biodex Medical Systems, USA) developed with acetonitrile \u0026minus;\u0026thinsp;0.9% NaCl (1v/1v).\u003c/p\u003e\n\u003ch3\u003eSterile filter integrity test:\u003c/h3\u003e\n\u003cp\u003eThe sterile filter (with needle still attached) was connected to a nitrogen supply via a regulator. The needle was submerged in water and the nitrogen pressure was gradually increased. If the pressure was raised above the filter acceptance pressure (3.2 bars) without seeing a stream of bubbles, the filter was considered intact (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eDose pH\u003c/h2\u003e \u003cp\u003eThe pH of a small amount of the [\u003csup\u003e18\u003c/sup\u003eF]Fallypride solution was determined using Macherey-Nagel\u0026reg; pH 2.0\u0026ndash;9.0 non-bleeding pH-indicator strips by visual comparison to the scale provided. As listed in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, the pH was ranging between 6.5 and 7.5.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eEndotoxin Analysis\u003c/h2\u003e \u003cp\u003eThe endotoxin content in the synthesized [\u003csup\u003e18\u003c/sup\u003eF]Fallypride was analyzed using a Endosafe\u0026reg; nexgen-PTS\u0026trade; from Charles River. Doses had to contain\u0026thinsp;\u0026le;\u0026thinsp;175 Endotoxin Units (EU) / mL to be deemed acceptable. Limulus-amoebocyte-lysate (LAL) test for bacterial endotoxin resulted\u0026thinsp;\u0026lt;\u0026thinsp;17.5 EU/ml in all analyzed samples (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eSterility Testing\u003c/h2\u003e \u003cp\u003eFluid thioglycolate media (FTM) plates and soybean casein digest agar media (SCDM) plates were treated with samples of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride. FTM plates were used to test for anaerobes, aerobes and micro aerophiles whilst SCDM plates were used to test for non-fastidious and fastidious microorganisms. [\u003csup\u003e18\u003c/sup\u003eF]Fallypride-treated plates were incubated with positive and negative controls for 14 days. FTM plates were incubated at 32\u0026deg;C and SCDM plates were incubated at 22\u0026deg;C according to the European Pharmacopoeia (Ph. Eur.). Plates were visually inspected on the 3rd, the 8th and the 14th day of the test and compared to the positive and negative standards. Positive standards had to show growth (turbidity) on the plates and [\u003csup\u003e18\u003c/sup\u003eF]Fallypride negative controls had to have no culture growth after 14 days to be indicative of sterility. All samples met the sterility specifications (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eThin layer chromatography spot test for determination of kryptofix-[2.2.2] and TBAHCO\u003csub\u003e3\u003c/sub\u003e content\u003c/h2\u003e \u003cp\u003eThe Kryptofix-[2.2.2] content was determined by using the thin layer chromatography technique on POLYGRAM\u0026reg; SIL G / UV254, 4 x 8 cm plate using a mixture of methanol and 25% ammonium hydroxide solution in water (90:10 v / v) as the mobile phase.\u003c/p\u003e \u003cp\u003eSpots of 1,0 \u0026micro;L of standard solution of Kryptofix-[2.2.2] or TBAHCO\u003csub\u003e3\u003c/sub\u003e in the concentration of 50 \u0026micro;g/mL, sample of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride, solvent (water: EtOH: 9:1) and positive control (500 \u0026micro;g/mL) were applied established 1 cm from the lower edge of the chromatographic sheet by means of an Eppendorf micro pipette. The samples were then dried with the aid of a hot air blower. The sheet was developed with the mobile phase and the dried sheets were then placed on a holder inside a glass chamber homogenously saturated with iodine vapor (ca. 5 gr) for 1 minute.\u003c/p\u003e \u003cp\u003eAny spot had not to be more intense than the reference solution, consequently containing only an equal or lower than 50 \u0026micro;g/mL of Kryptofix-[2.2.2] or TBAHCO\u003csub\u003e3\u003c/sub\u003e to meet Ph. Eur. requirements for the limit of Kryptofix-[2.2.2] impurities in \u003csup\u003e18\u003c/sup\u003eF-labelled radiopharmaceuticals.\u003c/p\u003e \u003c/div\u003e"},{"header":"RESULTS","content":"\u003cp\u003eAn improved GMP compliant synthesis method for [\u003csup\u003e18\u003c/sup\u003eF]Fallypride has been developed for both the cassette based synthesis system AllinOne (AiO) and the research synthesis module with fixed tubing (RNplus). [\u003csup\u003e18\u003c/sup\u003eF]Fallypride could be obtained ready for human use as physiological solution after purification on Alumina N Plus Light, Sep Pak Plus C18 and Sep Pak Light C18 cartridges and formulation with 1ml ethanol. The Radiochemical purity was \u0026gt;\u0026thinsp;98% and no contamination of the sterile solution with chemicals or solvents used during the synthesis was detected (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Representative chromatograms of radio HPLC and radio TLC are presented in Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eb. Repeated analyzes up to 4 h after synthesis showed that the radiochemical purity was still\u0026thinsp;\u0026gt;\u0026thinsp;95%.The method involves the abandonment of HPLC purification in favor of a faster and more convenient SPE purification method that led to [\u003csup\u003e18\u003c/sup\u003eF]Fallypride as physiological solution ready for human use meeting all required specifications for radiopharmaceuticals.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFor both synthesizers (AiO and RNplus) the optimization of the synthesis parameters in combination with the SPE cartridge purification results in [\u003csup\u003e18\u003c/sup\u003eF]Fallypride in high radiochemical yield (59% not decay corrected) in only 28 minutes when using TBAHCO\u003csub\u003e3\u003c/sub\u003e as phase transfer catalyst system and 31% (not decay corrected) in 40 minutes when using K\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e / Kryptofix-[2.2.2] (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe studies on the effect of the reaction temperature (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e), precursor amount (Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e) and reaction time (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e) show that the maximum radiochemical yield is reached at 95\u0026deg;, with 2 mg precursor and 10 minutes reaction time.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eIn recent decades there has been a shift in the field of automated synthesis modules for radiopharmaceuticals from the fixed tubing system, in which the liquid flow is regulated by inert gas, to a sterile disposable cassette system, in which the liquid flow is regulated by a syringe pump. One of the key advantages of the cassette system approach is that it provides greater microbiological safety and eliminates the risk of cross-contamination compared to the fixed tube approach. In this way, the GMP requirements are met better. However, cassette systems also have some disadvantages compared to fixed tubing systems. The main disadvantage of using disposable cassettes is their high cost and the dependency on the cassette manufacturers. Though, for both systems, in many cases, purification of the product using HPLC is necessary, which means additional complications and long synthesis times. In these cases, the possibility of using SPE cartridges instead of HPLC is highly desirable as it significantly simplifies the synthesis and increases flexibility.\u003c/p\u003e \u003cp\u003eIn a previous work by Moon et al. from 2010 the radio synthesis of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride was carried out by a labeling reaction using the phase transfer catalyst TBAHCO\u003csub\u003e3\u003c/sub\u003e (Moon, et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). They reported maximum radiochemical yield of approximately 45% (not decay corrected) at 100\u0026deg;C and a reaction duration of 51 minutes. Due to the need to use HPLC for the purification of the final product, this method is quite complex and needs long syntheses time. This circumstance may limit the application of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride in clinical practice and leads to relatively high dose cost rate. For this reason, we turned our attention to develop a simplified fast and high yielding automated synthesis using appropriate cartridges for the purification instead of an HPLC run.\u003c/p\u003e \u003cp\u003eUsing the Synthra RNplus research module with fixed tubing, we started with the synthesis of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride described by Moon et al. (Moon, et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2010\u003c/span\u003e) and replaced the HPLC purification by a Sep-Pak plus C-18 cartridge purification as described by Yang et al. (Yang, et al., 2008). However We found out that the recovery of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride was only 85%. Accordingly, 15% of the product was not retained by the cartridge and was lost as it was eluted through the Sep-Pak plus C-18 cartridge into the waste. In addition, the determined radiochemical purity using radio TLC analysis reveals a radiochemical purity of only\u0026thinsp;~\u0026thinsp;94% [\u003csup\u003e18\u003c/sup\u003eF]Fallypride (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea). For this reason, we introduced two modifications to the purification process. Firstly, we added a Sep-Pak Alumina-N cartridge as this was suggested to eliminate the non-reacted [\u003csup\u003e18\u003c/sup\u003eF]fluoride (Shao, et al., \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2011\u003c/span\u003e) and secondly, we added a second Sep Pak Light C18 cartridge to increase the trapping efficiency of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride and minimize its loss of into the waste. In this way the loss of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride into the waste was reduced to \u0026lt;\u0026thinsp;2% and the amount of [\u003csup\u003e18\u003c/sup\u003eF]Fluoride in the final product was eliminated. The radiochemical purity of the final product was \u0026gt;\u0026thinsp;98%. (Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eb)\u003c/p\u003e \u003cp\u003eNext, we focused on optimizing the labelling conditions to increase the radiochemical yield and to reduce the reaction time by optimizing the reaction temperature. We carried out two series of syntheses under different reaction temperatures using both the phase transfer catalysts systems TBAHCO\u003csub\u003e3\u003c/sub\u003e and K\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e/Kryptofix-[2.2.2]. The results are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e and show an optimal reaction temperature of about 95\u0026deg;C.\u003c/p\u003e \u003cp\u003eThe influence of precursor amounts on yields was then subsequently studied with five different precursor amounts of 1mg, 2mg, 2,5mg, 3mg, 4mg and 5mg at a reaction temperature of 95\u0026deg;C. The results are represented in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e. The maximum yield of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride was achieved when using 2 mg of precursor. The radiochemical purity was higher than 98% as shown in a representative HPLC- and TLC-radio chromatogram in Figs.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and \u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eb. This chromatogram shows a main peak corresponding to [\u003csup\u003e18\u003c/sup\u003eF]Fallypride with a retention time of 4.25 min accompanied by a small shoulder after this main peak. This poorly separated shoulder, which is probably caused by radiolysis, increased to about 3% of the total radioactivity when more than 3 mg of precursor was used. For this reason, the amount of precursor should not exceed 2 mg.\u003c/p\u003e \u003cp\u003eApplying the already found best conditions for the reaction temperature and precursor amounts (95\u0026deg;C with TBAHCO\u003csub\u003e3\u003c/sub\u003e; 90\u0026deg;C with K\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e/Kryptofix-[2.2.2]; 2 mg precursor) the effect of the reaction time was then examined. The experiments showed an optimal reaction time of 10 minutes with TBAHCO\u003csub\u003e3\u003c/sub\u003e and 20 min with K\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e/Kryptofix-[2.2.2] (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSince GMP regulations for radiopharmaceuticals tend to support single-use cassette systems, cartridge cleaning instead of HPLC cleaning in these systems simplifies operations and facilitates GMP compliance. In addition, the use of synthesizers with disposable cassettes increases reliability and enables rapid training of production personnel. Therefore, we transferred the conditions for the [\u003csup\u003e18\u003c/sup\u003eF]Fallypride synthesis obtained with the Synthra RNplus Research module to the AllinOne module from Trasis. The [\u003csup\u003e18\u003c/sup\u003eF]Fallypride synthesis with the AllinOne module applying these conditions and using the parameters as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e gave the same results as with the RNplus Research module.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eWe could successfully demonstrate that the synthesis of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride is practicable on commercial cassette-based systems as well as on customized modules with fixed tubing systems without the need for HPLC purification. The fully automated protocols are in accordance to GMP standards and allow the synthesis of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride without HPLC within 28 min including purification and formulation steps with high labeling yield as well as high radio chemical and radionuclide purity.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eGMP\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003egood manufacturing practice\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eHPLC\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003ehigh performance liquid chromatography\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003ePET\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003epositron emission tomography\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003ePh Eur\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eEuropean pharmacopeia\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eQC\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eQuality control\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eTLC\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003ethin-layer chromatography\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003eAcknowledgement\u003c/p\u003e\n\u003cp\u003eNot Applicable.\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eNot Applicable.\u003c/p\u003e\n\u003cp\u003eAuthor information\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAffiliations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDepartment of Nuclear Medicine, Molecular Diagnostic Imaging and Therapy, University Hospital of Schleswig-Holstein (UKSH), Karl Lennert Cancer Center North, D-24105 Kiel, Germany\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAmmar Alfteimi*, Yi Zhao*, Ulf L\u0026uuml;tzen, Alexander Helm, Michael J\u0026uuml;ptner, Maaz Zuhayra\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eContributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMZ: Conception and design of the work and oversaw the research project and approved the final manuscript. AA*: performed the chemistry and radiochemistry experiments and analyzed the results. YZ*, UL, AH and MJ contributed in writing and revising the manuscript and interpretation of the data. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e*: Both authors contributed equally to this manuscript\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCorresponding author:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eProf. Dr. Maaz Zuhayra\u003c/p\u003e\n\u003cp\u003eEthics declarations\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work does not contain any clinical study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo competing interests.\u003c/p\u003e\n\u003cp\u003eAvailability of data and materials\u003c/p\u003e\n\u003cp\u003eAll data generated or analyzed during this study are included in this published article.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAnsari, M., Kessler, R., Clanton, J., Paulis, T. D., \u0026amp; Baldwin, R. (2006, May 1). Comparison of three [18f]Fallypride methods intended for automated remote chemistry modules. Journal of Nuclear Medicine. https://jnm.snmjournals.org/content/47/suppl_1/159P.1 \u003c/li\u003e\n\u003cli\u003eBoschi, S., Lodi, F., Malizia, C., Cicoria, G., \u0026amp; Marengo, M. (2013a). Automation Synthesis Modules Review. Applied Radiation and Isotopes, 76, 38\u0026ndash;45. https://doi.org/10.1016/j.apradiso.2012.09.010 \u003c/li\u003e\n\u003cli\u003eBoschi, S., Lodi, F., Malizia, C., Cicoria, G., \u0026amp; Marengo, M. (2013b). Automation Synthesis Modules Review. Applied Radiation and Isotopes, 76, 38\u0026ndash;45. https://doi.org/10.1016/j.apradiso.2012.09.010 \u003c/li\u003e\n\u003cli\u003eCHRISTIAN, B., VANDEHEY, N., FOX, A., MURALI, D., OAKES, T., CONVERSE, A., NICKLES, R., SHELTON, S., DAVIDSON, R., \u0026amp; KALIN, N. (2009). The distribution of D2/D3 receptor binding in the adolescent rhesus monkey using small animal pet imaging. NeuroImage, 44(4), 1334\u0026ndash;1344. https://doi.org/10.1016/j.neuroimage.2008.10.020 \u003c/li\u003e\n\u003cli\u003eConstantinescu, C. C., Coleman, R. A., Pan, M., \u0026amp; Mukherjee, J. (2011). Striatal and extrastriatal micropet imaging of D2/D3 dopamine receptors in rat brain with [18f]Fallypride and [18f]desmethoxyfallypride. Synapse, 65(8), 778\u0026ndash;787. https://doi.org/10.1002/syn.20904 \u003c/li\u003e\n\u003cli\u003eHoner, M., Br\u0026uuml;hlmeier, M., Missimer, J., Schubiger, A. P., \u0026amp; Ametamey, S. M. (2004, March 1). Dynamic imaging of striatal D2 receptors in mice using quad-hidac pet. Journal of Nuclear Medicine. https://jnm.snmjournals.org/content/45/3/464.long \u003c/li\u003e\n\u003cli\u003eKrasikova, R. (2007). Synthesis modules and automation in F-18 labeling. Ernst Schering Research Foundation Workshop, 289\u0026ndash;316. https://doi.org/10.1007/978-3-540-49527-7_11 \u003c/li\u003e\n\u003cli\u003eLepareur, N. (2022). Cold kit labeling: The future of 68Ga radiopharmaceuticals? Frontiers in Medicine, 9. https://doi.org/10.3389/fmed.2022.812050 \u003c/li\u003e\n\u003cli\u003eMoon, B. S., Hyung Park, J., Jin Lee, H., Sun Kim, J., Sup Kil, H., Se Lee, B., Yoon Chi, D., Chul Lee, B., Kyeong Kim, Y., \u0026amp; Eun Kim, S. (2010). Highly efficient production of [18F]Fallypride using small amounts of base concentration. Applied Radiation and Isotopes, 68(12), 2279\u0026ndash;2284. https://doi.org/10.1016/j.apradiso.2010.06.016 \u003c/li\u003e\n\u003cli\u003eMukherjee, J., Yang, Z.-Y., Brown, T., Lew, R., Wernick, M., Ouyang, X., Yasillo, N., Chen, C.-T., Mintzer, R., \u0026amp; Cooper, M. (1999). Preliminary assessment of extrastriatal dopamine D-2 receptor binding in the rodent and nonhuman primate brains using the high affinity radioligand, 18F-fallypride. Nuclear Medicine and Biology, 26(5), 519\u0026ndash;527. https://doi.org/10.1016/s0969-8051(99)00012-8 \u003c/li\u003e\n\u003cli\u003eMukherjee, J., Yang, Z.-Y., Das, M. K., \u0026amp; Brown, T. (1995). Fluorinated benzamide neuroleptics\u0026mdash;III. development of (s)-n-[(1-allyl-2-pyrrolidinyl)methyl]-5-(3-[18f]fluoropropyl)-2,3-dimethoxybenzamide as an improved dopamine D-2 receptor tracer. Nuclear Medicine and Biology, 22(3), 283\u0026ndash;296. https://doi.org/10.1016/0969-8051(94)00117-3 \u003c/li\u003e\n\u003cli\u003eShao, X., Hoareau, R., Hockley, B. G., Tluczek, L. J., Henderson, B. D., Padgett, H. C., \u0026amp; Scott, P. J. (2011). Highlighting the versatility of the TRACERLAB synthesis modules. part 1: Fully automated production of [18f]labelled radiopharmaceuticals using a tracerlab FXfn. \u003cem\u003eJournal of Labelled Compounds and Radiopharmaceuticals\u003c/em\u003e, \u003cem\u003e54\u003c/em\u003e(6), 292\u0026ndash;307. https://doi.org/10.1002/jlcr.1865 \u003c/li\u003e\n\u003cli\u003eSiessmeier, T., Zhou, Y., Buchholz, H.-G., Landvogt, C., Vernaleken, I., Piel, M., Schirrmacher, R., R\u0026ouml;sch, F., Schreckenberger, M., Wong, D. F., Cumming, P., Gr\u0026uuml;nder, G., \u0026amp; Bartenstein, P. (2005, June 1). Parametric mapping of binding in human brain of D2 receptor ligands of different affinities. Journal of Nuclear Medicine. https://jnm.snmjournals.org/content/46/6/964/tab-article-info \u003c/li\u003e\n\u003cli\u003eSlifstein, M., Hwang, D.-R., Huang, Y., Guo, N., Sudo, Y., Narendran, R., Talbot, P., \u0026amp; Laruelle, M. (2004). In vivo affinity of [18F]Fallypride for striatal and extrastriatal dopamine D2 receptors in nonhuman primates. Psychopharmacology, 175(3), 274\u0026ndash;286. https://doi.org/10.1007/s00213-004-1830-x \u003c/li\u003e\n\u003cli\u003eVelikyan, I. (2015). 68ga-based radiopharmaceuticals: Production and application relationship. Molecules, 20(7), 12913\u0026ndash;12943. https://doi.org/10.3390/molecules200712913 \u003c/li\u003e\n\u003cli\u003eYang, M., Xu, Y., Pan, D., \u0026amp; Luo, S. (2008, May 1). Simplified radiosynthesis of 18F-Fallypride. Journal of Nuclear Medicine. https://jnm.snmjournals.org/content/49/supplement_1/307P.1 \u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"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":"ejnmmi-radiopharmacy-and-chemistry","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"erpc","sideBox":"Learn more about [EJNMMI Radiopharmacy and Chemistry](http://ejnmmipharmchem.springeropen.com)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/erpc/default.aspx","title":"EJNMMI Radiopharmacy and Chemistry","twitterHandle":"@officialEANM","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Automated radiosynthesis, Fallypride, D2/D3 receptors, F-18","lastPublishedDoi":"10.21203/rs.3.rs-6062704/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6062704/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e[\u003csup\u003e18\u003c/sup\u003eF]Fallypride PET has been used to study D2/3 receptor occupancy and density in neuropsychiatric disorders including Huntington’s disease (HD) and aging in humans. Nevertheless, the various synthetic methods including those provided by commercial synthesizers for [\u003csup\u003e18\u003c/sup\u003eF]Fallypride exhibit a disadvantage concerning the necessity using a HPLC purification step, which causes difficulties in the automation, leads to long synthesis times and moderate yields. Therefore utilizing the purification step by SPE cartridges is considered highly desirable for future commercialization of radiopharmaceutical cassettes. In our lab we have developed a simplified reliable automatic radio synthesis of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride by using SPE cartridges for the purification step without the need of HPLC.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA simplified radio synthesis of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride has been developed without the use of HPLC for both a commercial cassette based synthesis system (AllinOne (AiO) system, Trasis, Belgium) and a research synthesis module with fixed tubing (RNplus, Synthra, Germany). The cleaning step involves a serial combination of several SPE cartridges.\u003c/p\u003e\n\u003cp\u003eThe synthesis time was shortened by 44% compared to synthesis using HPLC. At the same time the not decay corrected yield increases from 44% to 59% by using TBAHCO\u003csub\u003e3\u003c/sub\u003e as phase transfer catalysts and from 17% to 31% for the synthesis with K\u003csub\u003e2\u003c/sub\u003eCO\u003csub\u003e3\u003c/sub\u003e/Kryptofix-[2.2.2] compared to synthesis using HPLC. The radio chemical purity was always \u0026gt;98% and all quality control parameters (e.g. sterility, endotoxin, stability and radio chemical purity) were conform to the European Pharmacopoeia.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA GMP compliant automatic synthesis of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride including purification using simple solid phase extraction cartridges instead of HPLC was developed and evaluated. The implementation of the simplified synthesis in both used commercial modules allows efficient and reproducible radio synthesis of [\u003csup\u003e18\u003c/sup\u003eF]Fallypride and leads to short synthesis times and high radiochemical yields with high radiochemical purity.\u003c/p\u003e","manuscriptTitle":"GMP compliant simplified fast and high yielding automated synthesis of [18F]Fallypride without the need of HPLC purification","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-03-05 06:44:38","doi":"10.21203/rs.3.rs-6062704/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2025-03-17T05:48:38+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2025-02-27T12:23:28+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-02-27T11:57:27+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-02-26T18:19:50+00:00","index":"","fulltext":""},{"type":"submitted","content":"EJNMMI Radiopharmacy and Chemistry","date":"2025-02-26T02:56:52+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"ejnmmi-radiopharmacy-and-chemistry","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"erpc","sideBox":"Learn more about [EJNMMI Radiopharmacy and Chemistry](http://ejnmmipharmchem.springeropen.com)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/erpc/default.aspx","title":"EJNMMI Radiopharmacy and Chemistry","twitterHandle":"@officialEANM","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"0fb4a4ce-e671-46a9-9672-0552a42d981d","owner":[],"postedDate":"March 5th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-05-05T16:02:38+00:00","versionOfRecord":{"articleIdentity":"rs-6062704","link":"https://doi.org/10.1186/s41181-025-00343-w","journal":{"identity":"ejnmmi-radiopharmacy-and-chemistry","isVorOnly":false,"title":"EJNMMI Radiopharmacy and Chemistry"},"publishedOn":"2025-05-04 15:57:00","publishedOnDateReadable":"May 4th, 2025"},"versionCreatedAt":"2025-03-05 06:44:38","video":"","vorDoi":"10.1186/s41181-025-00343-w","vorDoiUrl":"https://doi.org/10.1186/s41181-025-00343-w","workflowStages":[]},"version":"v1","identity":"rs-6062704","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6062704","identity":"rs-6062704","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}