Rapid synthesis of [18F]FDG without an evaporation step using an ionic liquid

In this study, we describe a new 2-[18F]fluoro-2-deoxy- -glucose ([18F]FDG) synthesis without a distillation step. This involves fluorinating in an ionic liquid-containing medium. A test for the effective elution of [18F]fluoride from the anion exchange resin showed the proper selection of the base and the required eluant composition, which is an essential requirement for the automation of [18F]FDG synthesis. An 18F-labeling study by nucleophilic substitution showed that the major factors controlling the yield were the temperature and the reaction medium composition. The 18F-fluorination proceeded with a labeling efficiency of 74.6±7.4% (n=8) for optimized conditions. Alkaline hydrolysis and purification carried out in the liquid phase provided a final decay-corrected [18F]FDG yield of 59.1±5.1% (n=3), a radiochemical purity of 91.9±3.7% (n=3), and a reaction time of 13 min. Alkaline hydrolysis and purification carried out in the solid phase provided a final decay-corrected [18F]FDG yield of 48.8±6.0% (n=3), a radiochemical purity of 96.0±4% (n=3), and a reaction time of 19 min. The rapid and straightforward synthesis of [18F]FDG can be achieved by eliminating all evaporation steps, which is made possible by the use of ionic liquid-containing media for the fluorination step.