Simple, column purification technique for the fully automated radiosynthesis of [18F]fluoroazomycinarabinoside ([18F]FAZA)

A novel fully automated radiosynthesis procedure for the fluorine-18 analog of 1-α-D-(5′-deoxy-5′-fluoro-(1S,2R,3S,4S) arabinofuranosyl)-2-nitroimidazole ([18F]FAZA) using a commercially available combination column - Chromabond® Set V (FDG-base-hydrolysis) - for purification was developed. [18F]FAZA was prepared via a one-pot, two-step synthesis using a nuclear interface nucleophilic synthesis module. Nucleophilic fluorination of the precursor molecule, 1-(2,3-di-O-acetyl-5-O-tosyl-α-D-arabinofuranosyl)-2-nitroimidazole, with no-carrier added [18F]fluoride followed by hydrolysis of the protecting groups with 0.3 M NaOH was performed. Purification was carried out using the Chromabond® Set V column without any modifications. The overall radiochemical yield obtained was 21.98±1.40% (n=5, without decay correction) within a total synthesis period of 51±1 min. The radiochemical purity was greater than 95% and devoid of any other chemical impurities. The reported method can easily be adapted in any commercial FDG synthesis module.