PLASMA-CONCENTRATIONS OF THE ENANTIOMERS OF HALOFANTRINE AND ITS MAINMETABOLITE IN MALARIA PATIENTS

The plasma concentrations of the enantiomers of halofantrine and its N -desbutyl metabolite in six patients with malaria were measured after oral administration of 3 x 750 mg doses of micronised, racemic halofan trine hydrochloride given at 6-hour intervals. Significant differences were observed between the plasma concentrations of the enantiomers bo th of halofantrine and its N-monodesbutyl metabolite. AUC(0)84h values were higher for (+)halofantrine (9917 mu g.ml(-1).h) than for (-)-hal ofantrine (6127 mu g.ml(-1).h). The clinical significance of these obs ervations is not known. The isomers have equipotent activity in vitro but their relative toxicity has not yet been assessed.