Pharmacokinetics of cocaine in pregnant and nonpregnant rhesus monkeys

Abstract To determine pharmacokinetic parameters for cocaine in rhesus monkey plasma, samples were taken over several hours after i.m. administration of cocaine plus a tritiated cocaine tracer. Cocaine and its metabolites, benzoylecgonine and norcocaine, were isolated via HPLC and quantitated using liquid scintillation spectrometry. Pregnant subjects were dosed with cocaine at 0.3 ( n = 3) or 1.0 ( n = 3) mg/kg, whereas nonpregnant female subjects were dosed with 1.0 mg/kg ( n = 3). For the pregnant subjects, pharmacokinetic studies were conducted on about gestational day 125 and areas under the concentration versus time curve (AUCs, ng/mL × h) were 64 ± 26 (±SEM) and 143 ±12; half-lives ( t 1 2 s, h ) were 1.9 ± 0.6 and 1.1 ± 0.1 after 0.3 and 1.0 mg/kg i.m., respectively. For nonpregnant subjects dosed acutely with 1.0 mg/kg, the AUC was 262 ± 63 and the t 1 2 was 1.4 ± 0.3 . There appear to be few differences in the pharmacokinetic parameters of cocaine and benzoylecgonine between pregnant and nonpregnant monkeys in this study.