Plasmodium yoelii nigeriensis (MDR) -: Efficacy of oral pyronaridine against multidrug-resistant malaria in Swiss mice

Plasmodium yoelii nigeriensis (MDR)-Efficacy of oral pyronaridine against multidrug-resistant malaria in Swiss mice. Experimental Parasitology 94. 190-193. A multidrug-resistant strain of Plasmodium yoelii nigeriensis (MDR) showing a wide spectrum of resistance to chloroquine, amodiaquine, mepacrine, mefloquine, halofantrine, quinine, and quinidine was used in this study for in vivo evaluation of the blood schizontocidal activity of pyronaridine, a topoisomerase II inhibitor, in Swiss mice. The parasite produces 100% lethal infection in mice. The drug was administered orally once a day from day 0 onward. The initial studies showed that low doses of pyronaridine (0.625 to 5.0 mg base/kg X 9 days) did not completely control blood induced P. yoelii nigeriensis infection. Finally a series of doses of pyronaridine ranging from 1.25 to 30.0 mg/kg administered orally for 7 consecutive days were evaluated and in spite of high level of resistance to standard antimalarials, the parasite P. yoelii nigeriensis has shown complete susceptibility to pyronaridine (15 mg/kg dose X 7 days). The present paper also compares the merits of a single MDR strain vs a battery of different resistant lines for quick antimalarials screening. (C) 2000 Academic Press.