Evaluation of the radiochemical impurities arising during the competitive fluorination of nosyl group during the synthesis of 3′-deoxy-3′-fluorothymidine, [18F]FLT

摘要

The study is aimed at the analysis and identification of radiochemical and chemical impurities present in [18F]FLT synthesized by a simplified combination-column purification procedure, instead of the currently used HPLC purification. HPLC analysis of the final product showed an anionic radioactive byproduct, which was established as [18F]4-FBSA. The identity of the product was also confirmed by the radiofluorination of nosyl chloride. Mass spectrum analysis of both a decayed sample of [18F]FLT and fluorinated nosyl chloride showed a major peak at 242. We have also investigated the possible interference of this byproduct during PET-imaging in rabbits. Keywords [18F]FLT - FLT-synthesis - Nosyl fluoride - Radiofluorination