Elimination of contaminant Kryptofix 2.2.2 in the routine production of 2-[18F]fluoro-2-deoxy-D-glucose.

Radiopharmaceutical solutions of 2-[18F]fluoro-2-deoxy-D-glucose (2-[18F]FDG) prepared via an aminopolyether-supported nucleophilic-substitution mechanism were analyzed for contaminant 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo-[8,8,8]-hexacosane (Kryptofix 2.2.2). Washing the C18-immobilized [18F]fluoro-tetraacetylated intermediate with 10 mL 0.1 M HCl was found to remove impurity Kryptofix 2.2.2 from the final product. Inclusion of this synthetic step allowed the robotic production of drug-quality 2-[18F]FDG in 52-56% radiochemical yield within 75 min. A thin-layer chromatographic system for the clinical screening of the radiochemical and chemical purity of this radiopharmaceutical is described.