Susceptibility of in vitro cultured Plasmodium falciparum to chloroquine and combination of sulfadoxine and pyrimethamine

Keittivuti B., Keittivuti A. and Panichacheewakul P. 1982. Susceptibility of in vitro cultured Plasmodium falciparum to chloroquine and combinations of sulfadoxine and pyrimethamine. International Journal for Parasitology12: 383–387. The culture of P. falciparum in RPMI 1640 media in vitro was used for testing antimalarial drugs on blood from 11 patients at the Malaria Eradication Center, Phabuddhabat District, Saraburi Province, Thailand. Chloroquine in concentrations of 1, 3 and 4 nmol, combinations of sulfadoxine and pyrimethamine at 0.05 mg + 2.5 μg, 0.10 mg + 5 μg and 0.20 mg + 10 μg respectively and 1.4 μg sodium hydroxide/ml of blood were used. The organisms in the culture were resistant to the action of the combinations of sulfadoxine and pyrimethamine but were susceptible to chloroquine particularly at the 3 and 4 nmol levels. The in vitro test system used offers a valuable tool for studying the activity of antimalarial drugs.