Radiosynthesis of 10-(2-[~(18)F]fluoroethoxy)-20(S)-camptothecin as a potential positron emission tomography tracer for the imaging of topoisomerase I in cancers

摘要

The preparation of 10-(2-[~(18)F]fluoroethoxy)-20(S)-camptothecin, a potential positron emission tomography tracer for the imaging of topoisomerase I in cancers, is described. 10-(2-[~(18)F]Fluoroethoxy)-20(S)-camptothecin was synthesized by the [~(18)F]fluoroalkylation of the corresponding hydroxy precursor molecule with 2-[~(18)F]fluoroethyl bromide ([~(18)F]FEtBr) in dimethylsulfoxide (DMSO) at 55 ℃ for 20 min; this was followed by purification using high performance liquid chromatography (HPLC) with a total preparation time of 60 min. The overall radiochemical yield was approximately 5.4–12 % (uncorrected), and the radiochemical purity was above 96 %.