Pharmacokinetic data on tritium labelled ethyl apovincaminate

Absorption, tissue distribution and excretion of tritium labelled ethyl apovincaminate (RGH-4405, Cavinton) were studied. Both oral and i.p. administration resulted in a relatively rapid elimination of tritium activity, suggesting that neither the original drug nor its metabolites remained in the organism of rat. 50% of radioactivity was recovered in urine and 30% in faeces during 48 h. At this time only liver and kidneys contained measurable quantities of radioactivity among the organs tested. Biliary route of elimination seemed to be important, since 20% and 4% of radioactivity appeared in bile during 9 h following i.p. and p.o. administration, respectively. Enterohepatic circulation was of no consequence. Radioactivity was hardly adsorbed to or absorbed by blood cells and was almost completely bound by plasma protein(s).