ABSTRACT
Plasmodium species ex vivo sensitivity assay protocols differ in the requirement for leukocyte removal before culturing. This study shows that the presence of leukocytes significantly increases the 50% inhibitory concentration (IC50) of P. vivax and P. falciparum to artesunate and chloroquine relative to results with the paired leukocyte-free treatment. Although leukocyte removal is not an essential requirement for the conduct of ex vivo assays, its use has important implications for the interpretation of temporal and spatial antimalarial sensitivity data.
Subject(s)
Antimalarials/pharmacology , Artemisinins/pharmacology , Chloroquine/pharmacology , Leukocytes/physiology , Plasmodium falciparum/drug effects , Plasmodium vivax/drug effects , Artesunate , Humans , Inhibitory Concentration 50 , Parasitic Sensitivity TestsABSTRACT
The novel organometallic chloroquine analog ferroquine (SSR 97193) is effective against chloroquine-resistant Plasmodium falciparum. The ex vivo efficacy of ferroquine against Plasmodium vivax isolates was tested. Ferroquine has a potent ex vivo effect on P. vivax schizont maturation (median 50% inhibitory concentration, 15 nM; n = 42). No significant cross-sensitivity between ferroquine and other antimalarials was detected. This drug may be a suitable replacement for chloroquine in the treatment of drug-resistant P. vivax malaria.
