Automated GMP production and long-term experience in radiosynthesis of CB tracer [ F]FMPEP-d.

Here, we describe the development of an in-house-built device for the fully automated multistep synthesis of the cannabinoid CB receptor imaging tracer (3R,5R)-5-(3-([ F]fluoromethoxy-d )phenyl)-3-(((R)-1-phenylethyl)amino)-1-(4-(trifluoromethyl)phenyl)pyrrolidin-2-one ([ F]FMPEP-d ), following good manufacturing practices. The device is interfaced to a HPLC and a sterile filtration unit in a clean room hot cell. The synthesis involves the nucleophilic F-fluorination of an alkylating agent and its GC purification, the subsequent F-fluoroalkylation of a precursor molecule, the semipreparative HPLC purification of the F-fluoroalkylated product, and its formulation for injection. We have optimized the duration and temperature of the F-fluoroalkylation reaction and addressed the radiochemical stability of the formulated product. During the past 5 years (2013-2018), we have performed a total of 149 syntheses for clinical use with a 90% success rate. The activity yield of the formulated product has been 1.0 ± 0.4 GBq starting from 11 ± 2 GBq and the molar activity 600 ± 300 GBq/μmol at the end of synthesis.