Synthesis and distribution kinetics of 11C-chlorpromazine in animals

A study on animals of the fast distribution kinetics of 11C-chlorpromazine hydrochloride administered intravenously shows, in both rabbits and monkeys, a very early radioactivity build-up in the brain and lungs (immediately after injection). The lung and brain activities develop and decrease during the experimental period (about 60 min) whereas that of the liver increases. Quantitative results obtained on mice after removal of the organs and counting of the activity obtained by intravenous injection of 11C-chlorpromazine hydrochloride prove that the radioactivity observed is indeed an accumulation and is not due to passage of the blood flow, the blood activity remaining low throughout. No tumor fixation of 11C-chlorpromazine was observed in the mice under our experimental conditions. A quantitative kinetics study of 11C-chlorpromazine in vivo is not easy to pursue in animals such as rabbits or monkeys, and even less so in mice, in view of the size of the animal and the resolution of the gamma camera collimator. But this, we think, is relatively unimportant as the aim of this work is to prepare for the application to humans of this new pharmacokinetics method