Kinetic metabolism of vinpocetine in the rat

The pharmacokinetics of vinpocetine (Cavinton), a new potent vasodilator, and of its main metabolite have been studied in rats by specific extraction and radio thin-layer chromatography following i.v. and p.o. administration. The drug is rapidly eliminated, its half-life was found to be 125 min. The apparent volume of distribution was 3.8 l/kg and the clearance rate 33 ml/min/kg. From the equation describing the concentration-time curve a two-compartement open model was computed. Bioavailability of vinpocetine after p.o. administration was about 50%. The main metabolite, free apovincaminic acid, is formed very rapidly in rats and is eliminated from plasma with a half-life of 360 min.