[Pharmacokinetic studies of 14C-labeled epervudine in rats]

The characteristics of absorption, distribution and elimination of 14C-labelled epervudine were studied in rats treated with 10 mg/kg doses orally and intravenously. The blood level curves were analyzed by appropriate pharmacokinetic models. The results of oral treatment showed a rapid absorption of the radioactivity from the gastrointestinal tracts of the animals (tmax (0.75 h). The elimination rate of radioactivity from blood was fast (t1/2 el = 5.53 h). Blood level curves were characterized by a rapid initial distribution phase after intravenous treatment (t1/2 alpha = 0.17 h). Subsequently, the rate of elimination became slower and the concentration of radioactivity remained at a low level between 2 and 24 hours after the treatment. Studies of distribution did not reveal any specific tissue accumulation. As shown by excretion studies, the elimination of the radioactivity was fast following both the oral and intravenous administration. Within 24 hours ca. 50% excreted with urine and ca. 20% with feces. The ratio areas under blood level curves demonstrated an absorption of 70% (AUCpo: AUCiv x 100).