Comparative pharmacology of amphotericin B and amphotericin B methyl ester in the non-human primate, Macacca mulatta.

The pharmacokinetics of amphotericin B methyl ester hydrochloride (AME) and commercial deoxycholate-stabilized amphotericin B (AMB) were compared after single doses of 5 mg and 1 mg/kg of body weight, respectively, given intravenously in a period of 3 h to adult female rhesus monkeys (Macaca mulatta). By bioassay, the concentrations of AME were 12.2 to 7.2 times higher in the serum and 7.8 to 2.5 times higher in the urine during the 8 h after infusion. The decline in concentrations of the drugs in sera was consistent with a three-compartment, open pharmacokinetic model; rate constants of transfer of the drugs between the compartments and volumes of distribution were calculated. The overall rate of elimination from the central compartment (the bloodvascular space) was about four times greater for AME than for AMB. Serum urea nitrogen and creatinine concentrations were mildly and transiently increased after infusion of AME, whereas the more severe azotemia that followed infusion of AMB persisted for 5 days. AME was less toxic and achieved a greater urinary outfall than AMB. As the antifungal activity of AME is comparable to that of AMB by testing in vitro, further study is warranted.