Direct comparison of antimalarial activity among PS-15 combination therapies by bioassay of serum samples from...

Sixteen Saimiri sciureus monkeys were administered PS-15-atovaquone, PS-15-sulfamethoxazole, PS-15-dapsone, PS-15 alone, and atovaquone alone. The in vitro antimalarial activity of serum against Plasmodium falciparum obtained from these monkeys at 3, 6, and 12 hr after the administration of drug(s) were measured by bioassay and analyzed by Duncan's and Newman-Keul's tests. PS-15-atovaquone was found to be the most effective antimalarial combination, followed by PS-15-sulfamethoxazole, PS-15-dapsone, PS-15 alone, and atovaquone alone. These dual PS-15 combinations are effective combinations and, in-particular, PS-15-atovaquone is worthy of further evaluation.