The pharmacokinetics of artemisinin after administration of two different suppositories to healthy Vietnamese subjects

, Eight healthy Vietnamese male subjects received 400 mg artemisinin formul ated into fatty suppositories (FS), and six different subjects received 500 mg of artemisinin formulated in polyethylene glycol suppositories (PEGS). Plasma concentrations were measured by high-performance liquid chromatograp hy with electrochemical detection; concentration versus time curves were an alyzed with nonparametric methods. No statistically significant differences were found between the two formulations. The maximum concentration (Cmax) was 100 +/- 102 mu g/L (mean +/- SD, range = 24-330) mu g/L (FS), the pharm acokinetic lag time (Tlag) was 1.3 +/- 1.0 hr (range = 0-3) (FS), and the t ime of the maximum concentration (Tmax) was 7.1 +/- 2.1 hr (range 3-10) hr (FS). Because artemisinin is nor available for intravenous dosage, absolute bioavailability cannot be assessed. However, compared with a pre vious stu dy on oral artemisinin in healthy Vietnamese subjects, bioavailability rela tive to oral administration was estimated to be approximately 30%. We concl ude that therapeutic blood concentrations of artemisinin can be reached aft er rectal dosage. The dose after rectal administration should probably be h igher than after oral administration; doubling or tripling the oral dose mi ght be necessary, which would imply a rectal dose of at least 20 mg/kg of b ody weight given twice a day,