Pharmacokinetics of apovincaminic acid in dogs

After the oral or intravenous administration of 10 mg vinpocetine to dogs the pharmacokinetics of its main metabolite, apovincaminic acid (AVA) can be described by a two-compartment open model. The apparent half-life of its formation was 0.56 +/- 0.23 h and that of the apparent elimination was 9.6 h which did not significantly differ from the elimination half-life of total radioactivity (8.16 +/- 1.77 h) and from the apparent elimination half-life of vinpocetine itself (8.9 +/- 2.87 h). The volume of distribution of AVA was 2.3 times lower than that of vinpocetine and its clearance value (1.5 +/- 0.77 1 h-1 kg-1) was 2.8 times less than that of vinpocetine. These results suggest that AVA does not undergo further metabolism and its elimination is formation limited.