Highly efficient production of [(18)F]fallypride using small amounts of base concentration

To minimize the base concentration of a phase-transfer catalyst, [(18)F]fluoride was extracted from (18)O-enriched water trapped on an activated ion exchange cartridge (Chromafix PS-HCO(3)) using different concentrations of tetrabutylammonium bicarbonate (TBAHCO(3)) or Kryptofix 2.2.2./K(2)CO(3) in organic solvents such as CH(3)CN/H(2)O or MeOH/H(2)O. The optimal labeling condition for [(18)F]fallypride with automated synthesis was that 2 mg of tosyl-fallypride in acetonitrile (1 mL) was heated at 100 degrees C for 10 min using 40% TBAHCO(3) (10 microL). [(18)F]Fallypride was obtained with a high radiochemical yield of approximately 68+/-1.6% (decay-corrected, n=42) with a total synthesis time of 51+/-1.2 min, including HPLC purification and solid-phase purification for the final formulation.