Optimization of the radiosynthesis of [(18) F]MEFWAY for imaging brain serotonin 1A receptors by using the GE TracerLab FXFN-Pro module

The aim of this study was to develop a highly reliable radiofluorination method for the preparation of N-{2-[4-(2-methoxyphenyl)piperazinyl]ethyl}-N-(2-pyridyl)-N-(4-(18) F-fluoromethylcyclohexane)carboxamide ([(18) F]Mefway) by using a fully automated system. The optimal condition is composed of two parts. The extraction system of the trapped F-18 in the anion exchange resin (i.e., quaternary methylamine cartridge) is a complex of Kryptofix 2.2.2. (K222, 4 mg/0.9 mL methanol) and K2 CO3 (1 mg/0.1 mL H2 O). After removing the solvents, the trans-tosylated Mefway precursor (1 mg/0.5 mL acetonitrile) was reacted with dried K222-K[(18) F] at 100°C for 5 min. After purification and formulation, [(18) F]Mefway was obtained with 38 ± 2.4% (decay corrected, n = 34) radiochemical yield, a total synthesis time of 52 ± 3.4 min, specific activity was 120.6 ± 8.7 GBq/µmol at the end of synthesis and a radiochemical purity of 99%. According to the quality control tests, formulated [(18) F]Mefway is suitable to apply parenteral clinical application.