Ex vivo evaluation of N-(3-[18F]fluoropropyl)-2β-carbomethoxy-3β-(4-fluorophenyl)nortropane in rats

IntroductionThe dopamine transporter (DAT) ligand N-(3-fluoropropyl)-2β-carbomethoxy-3β-(4-fluorophenyl)nortropane (β-CFT-FP) was labeled with fluorine-18, and its biodistribution was evaluated in rats ex vivo.MethodsThe distribution of 18F radioactivity in the brain and peripheral organs and tissues was determined at several time points 5–120 min after intravenous injection of [18F]β-CFT-FP.ResultsThe highest brain uptake of [18F]β-CFT-FP was localized in the striatum; limbic structures also exhibited high uptake. Low uptake was found in the cerebellum. The highest ratio of striatum-to-cerebellum uptake, already reached within 5 min, was 3.1. Pretreatment with the selective DAT inhibitor GBR12909 significantly decreased [18F]β-CFT-FP uptake in the striatum. In most peripheral tissues, the highest uptake was found at 5 min, indicating fast washout of the radioligand. Some accumulation of 18F radioactivity was seen in bone as a function of time, reflecting defluorination of the radioligand.ConclusionThe results indicate that [18F]β-CFT-FP is a potential radioligand for studying DAT in vivo with positron emission tomography.