Pharmacokinetics of cocaine in maternal and fetal rhesus monkeys at mid-gestation

We compared pharmacokinetics of cocaine and its metabolite, benzoylecgonine, in pregnant rhesus monkeys and their fe-tuses at mid-gestation: 1) after a single intravenous dose of cocaine, 2) after a single oral dose of cocaine, 3) after the last oral cocaine administration of a 50-day-long chronic cocaine treatment, and 4) on the last day of a 50-day-long chronic treatment with five daily intravenous cocaine injections. We found that intravenous administrations of cocaine produced maximal maternal levels of benzoylecgonine below the plasma levels for cocaine. In contrast, oral administrations resulted in the maximal maternal plasma levels of this metabolite signifi-cantly above those of cocaine. The bioavailability of the orally administered cocaine was calculated as 25%. Cocaine was detectable in the fetal plasma at maximal levels of approxi