In vitro schizontocidal activity of standard antimalarial drugs on chloroquine-sensitive and chloroquine-resistant isolates of Plasmodium falciparum

The expanding foci of multiple drug resistant malaria and emergence of different strains requires the reassessment of antimalarial activity with various drugs. In vitro response of a chloroquine sensitive and a chloroquine resistant isolate of P. falciparum to a group of 6 quinine derived and 3 artemisinin derived standard drugs has been screened, to evaluate schizontocidal activity of the drugs. In a conventional test system the IC50s were derived from the log dose response curves and evaluated by a rigorous statistical interpretation. Analysis by Tukey's test was significant for the quinine related drugs (Q < or = 0.01) and excludes the statistical significance of artemisinin related drugs in these isolates. The dose-responses of these two isolates vary with quinine derivatives, with some overlap at lower doses for the sensitive isolate than for the resistant one which manifests at higher doses.