Assessment of pharmacokinetic compatibility of short acting CDRI candidate trioxane derivative, 99–411, with long acting prescription antimalarials, lumefantrine and piperaquine

The pharmacokinetic compatibility of short-acting CDRI candidate antimalarial trioxane derivative, 99–411, was tested with long-acting prescription antimalarials, lumefantrine and piperaquine. LC-ESI-MS/MS methods were validated for simultaneous bioanalysis of lumefantrine and 99–411 and of piperaquine and 99–411 combinations. The interaction studies were performed in rats using these validated methods. The total systemic exposure of 99–411 increased when administered with either lumefantrine or piperaquine. However, co-administration of 99–411 significantly decreased the systemic exposure of piperaquine by half-fold while it had no effect on the kinetics of lumefantrine. 99–411, thus, seemed to be a good alternative to artemisinin derivatives for combination treatment with lumefantrine. To explore the reason for increased plasma levels of 99–411, an in situ permeability study was performed by co-perfusing lumefantrine and 99–411. In presence of lumefantrine, the absorption of 99–411 was significantly increased by 1.37 times than when given alone. Lumefantrine did not affect the metabolism of 99–411 when tested in vitro in human liver microsomes. Additionally, ATPase assay suggest that 99–411 was a substrate of human P-gp, thus, indicating the probability of interaction at the absorption level in humans as well.