New automated synthesis of [18F]FP-CIT with base amount control affording high and stable radiochemical yield: a 1.5-year production report

Abstract

We describe new [(18)F]Fluoropropylcarbomethoxyiodophenyl-nor-tropane ([(18)F]FP-CIT) automatic preparation method by (1) using 2-methyl-2-butanol as [(18)F]fluorination solvent, (2) base amount control to minimize side reaction and (3) salt elution method to elute trapped [(18)F]fluoride. We developed manual synthesis procedures for automatic synthesis application. In this manual synthesis, we trapped [(18)F]F(-) on ion exchange cartridge and eluted with 0.2 M potassium methanesulfonate solution. We have [(18)F]fluorination at 100°C with 2-methyl-2-butanol as protic solvent for [(18)F]fluorination. After high-performance liquid chromatography analysis, we have 69.3±3.2% of [(18)F]F(-) incorporation ratio on the manual synthesis and applied these conditions to automatic preparation with GE TracerLab FX module. After setting-up of automatic synthesis and quality control procedures for clinical procedures, we have routine production of [(18)F]FP-CIT with 86.9±9.5 GBq/2.5 ml of [(18)F]F(-) as initial radioactivity and have 192 productions for 1.5 year. We have 42.5±10.9% of decay corrected radiochemical yields and they were satisfied all quality control procedures and stability to 6 h. New [(18)F]FP-CIT automatic preparation method showed high and reliable radiochemical yield and we could have enough >35 patient doses of [(18)F]FP-CIT from one production.