6-[18F]fluoro-dehydroascorbic acid. Synthesis and tissue distribution in mice

6-Deoxy-6-[18F]fluoro-L-threo-2,3-hexodiulosonic acid γ-lactone (6-[18F]fluoro-dehydroascorbic acid, 18F-FDHA) was synthesized by oxidation of 6-deoxy-6-[18F]fluoro-L-ascorbic acid (18F-DFA) with Br2, a route that is analogous to the original synthesis of FDHA, in order to develop a radiotracer for nuclear medical imaging. Tissue biodistribution of 18F-FDHA in fibrosarcoma-bearing mice showed a low accumulation of radioactivity in the brain, with both substantial in vivo defluorination and low tumoral uptake levels. Several organs of mice unfed for 24 h showed a more significant increase in radioactivity postinjection of 18F-FDHA than did fed mice. Co-injection with 2-deoxyglucose of 18F-FDHA did not significantly alter brain and tumor uptake, as confirmed by tissue-to-blood ratios, and as compared to control experiments. Thus, 18F-FDHA does not exhibit desirable properties as a brain-targeting imaging agent for ascorbic acid bioactivity. (author)