Pharmacokinetic and metabolic studies of vinpocetine on dogs. I. Pharmacokinetics

Abstract

The pharmacokinetics of tritiated vinpocetine has been studied on dogs. The drug, when administered orally, was readily absorbed from the gastrointestinal tract (T1/2 0.3 h) and underwent similarly fast distribution (T1/2 0.8 h) in the organism. The mean value of the elimination half-life was 8.2 h. Approx. 75% of the administered radioactivity was excreted with urine and feces within 72 h. The pharmacokinetics of the intravenously administered, labelled compound showed that a similarly rapid distribution but a somewhat slower elimination took place. Fecal and urinary excretion of radioactivity applied amounted to about 82%. Investigation of the distribution of radioactivity between plasma and blood cells revealed that the radioactivity content did not bind to the cellular fraction of the blood. Pharmacokinetic studies of the same design in the literature allowed us to make some comparison between dogs, rats and humans in respect to the kinetic behavior of labelled vinpocetine.