大鼠体内麻黄汤中总生物碱的药代动力学考察及其与盐酸麻黄碱含量变化的比较

目的:考察麻黄汤中总生物碱在大鼠体内的药代动力学过程,比较其与盐酸麻黄碱的体内含量变化。方法:大鼠口服灌入麻黄汤,于不同时间点眼眶取血,采用酸性染料比色法测定血浆样品中总生物碱含量,通过3P97软件进行房室模型拟合并计算药代动力学参数,利用HPLC测定血浆样品中盐酸麻黄碱含量,比较二者在大鼠体内的含量变化。结果:总生物碱在4~144 mg·L-1与吸光度呈良好线性关系。总生物碱在大鼠体内的代谢过程符合一室模型,t1/2=339.88 min,tmax=265.86 min,AUC=326 631.38 min·mg·L-1;盐酸麻黄碱10 min入血,但在第6 h基本未能测出。结论:酸性染料比色法可用于麻黄汤中总生物碱的药代动力学分析,方法准确可靠。盐酸麻黄碱入血、消除均较快。

Investigation of Pharmacokinetics of Total Alkaloid from Ephedra Decoction in Rats and Its Comparison with Content Change of Ephedrine Hydrochloride

Objective:To investigate pharmacokinetics of total alkaloids from ephedra decoction in rats and compare content change between it and ephedrine hydrochloride. Method:Rats were oral administered with ephedra decoction and their orbital blood samples were taken at different time points.The content of total alkaloids in plasma samples was determined by acid dye colorimetry,pharmacokinetical parameters and compartment models of each composition were calculated or fitted by 3P97 software,the content of ephedrine hydrochloride in plasma samples was determined by HPLC and then compared wth results of total alkaloids. Result:Absorbance of total alkaloids calculated by ephedrine hydrochloride showed a good linear relationship with its concentration in a range of 4-144 mg·L^-1.In vivo metabolic process of total alkaloids in rats was complied with the one-compartment model with t1/2=339.88 min,tmax=265.86 min and AUC=326 631.38 min·mg·L^-1; however, the content of ephedrine hydrochloride in plasma could be determined in 10 min and not be determined after 6 h by HPLC,which indicated it was completely excreted soon. Conclusion:Acid dye colorimetry was accurate and reliable for determination of total alkaloids from ephedra decoction in rat plasma.Ephedrine hydrochloride got into blood and eliminated all fast.