双氢青蒿素对小鼠抗疟作用的药效动力学

PHARMACODYNAMICS OF DIHYDROARTEMISININE AGAINST PLASMODIUM BERGHEI IN MICE

双氢青蒿素(DHA)是青蒿素的一种还原产物,对感染伯氏疟原虫ANKA株的小鼠一次im给药,其抗疟作用的量—效关系和时—效关系可分别用y=4.9960+2.9536x和y=7.2654-0.3414t表达,进而估算出其ED_(50)和ED_(50)分别为1.00±0.13 mg/kg和2.72±0.70 mg/kg以DHA 5.0 mg/kg im后其药效下降一半的时间为6.6 h,体内有效药量的消除速率常数k为0.2662 h^(-1),效量半衰期为2.6 h。式中y为机率单位,是DHA对疟原虫抑制作用的估算值,x为对数剂量,t为DHA im后的间隔时间。

Dihydroartcmisinine (DHA) is a derivative of qinghaosu(arternisinine), which is an antimalarial drug. DHA was given to mice inoculated with Plasmodium berhgei ANKA strain by intramuscular injection. Within proper dose range, the dose-effect and time-effect curves of DHA against the malaria can be described by y= 4.9960+2.9536 x and y= 7.2654-0.3414 t, respectively, where y is the estimated value of parasitemia suppressing rate in probit ;x is log dose; t is the period since drug administration im. Accordingly,the ED_(50)= 1.00± 0.13 mg/kg and the time of half-effect was 6.6 h, when the dose was 5.0 mg/kg ira. The elimination rate constant of the effective dose in vivo was 0.2662h^(-1)with a half-life of 2.6 h.