Studies on the distribution of 14C-sulpiride and its metabolites in the rat and guinea pig.

After ip. injection of 14C-labelled sulpiride in rats, about one third is metabolized while the other two thirds are excreted unchanged in feces and urine. The highest level of its metabolites was found in the liver (about 65% of total radioactivity). In the brain, 90% of the radioactivity consisted of unchanged sulpiride, which seems to be responsible for the central effects of the drug. The highest concentrations within the brain were found in the median eminence, circumventricular organs, plexus, and pineal body.