Therapeutic Efficacy of Naphthoquine Phosphate Combined with Artemisinine against Plasmodium knowlesi / 中国寄生虫学与寄生虫病杂志

ABSTRACT

Objective To study the antimalarial activity of naphthoquine phosphate combined with artemisinine against Plasmodium knowlesi in rhesus monkey.Methods Monkeys were randomly divided into 9 groups(3/group).The monkeys in groups A and B were treated i.g.once daily for 3 days with 6 or 10 mg/kg of naphthoquine phosphate respectively.Those in groups C and D were treated i.g.twice for the 1st day and once for the 2nd and 3rd day with 31.6 or 100 mg/kg of artemisinine respectively.In groups E, F and G, they were treated i.g.only once with the combination of naphthoquine phosphate 10 mg/kg and artemisinine 10, 20 or 25 mg/kg respectively.Groups H and I served as controls which were treated i.g.only once with 10 mg/kg of naphthoquine phosphate and 30 mg/kg of artemisinine respectively.Parasitemia was examined beginning 24 h after drug administration.The observation lasted 105 days when no more parasite was found.Results At 24 h after drug administration, the parasite reduction rate in all groups was higher than 90%.The parasite clearance time for groups E, F and G was(56.0?16.0),(53.3?4.6), and(56.0?8.0) h respectively, more rapid than that of Group H(69.3?4.6) h.There were 1, 3, 3, 2, 2, and 3 monkeys in groups A, B, D, E, F, and G respectively which were cured.No monkeys were cured in groups C, H and I.Conclusion The combination of naphthoquine phosphate and artemisinine is superior to the single component and the optimum proportion in the combination is 12.5 in treating P.knowlesi infection in monkeys.