人肝微粒体中尼莫地平及其脱氢代谢物的HPLC测定法及代谢动力学

目的：建立人肝微粒体中尼莫地平及其代谢物的HPLC测定法,并用本法研究尼莫地平在肝微粒体中代谢的动力学。方法：采用HPLC法，色谱柱为Hypersil C₁₈柱，流动相为乙腈—水(62∶38)检测波长UV 238 nm，样品用乙醚—正己烷(1∶1)提取。结果：本法的回收率为94.3%～98.5%,日内和日间RSD为1.45%～9.68%,尼莫地平和其脱氢代谢物的浓度分别在1.31～20.92 μg.mL^-1和122.7～4908.0 ng.mL^-1范围内与峰面积呈良好线性关系。在本实验条件下尼莫地平呈线性消除,而其脱氢代谢物呈线性增加。结论：尼莫地平在人肝微粒体内被迅速代谢,肝微粒体P450酶参与了尼莫地平的脱氢氧化。

DETERMINATION OF NIMODIPINE AND ITS DEHYDROGENATION METABOLITE IN HUMAN LIVER MICROSOME BY HPLC AND ITS METABOLIZING KINETICS

AIM: To develop an HPLC method for the determination of nimodipine and its major metabolite as well as the kinetics of its metabolism in human liver microsomes. METHODS: Chromatography was performed on an Hypersil BDS C₁₈ column. An acetonitrile-water(62∶38) mixture as the mobile phase was used with the UV detector set at 238 nm. Following alkalinization with NaOH human liver microsomes were extracted with n-hexane-ether(1∶1). RESULTS: The recovery of of nimodipine and its major metabolite for the proposed method was more than 94.3%. The relative standard deviations for within-day and between-day were <9.68%. The calibration curve was linear in the range from 1.31 to 20.92 μg.mL^-1with γ=0.9997 for nimodipine and from 122.7 to 4908.0 ng.mL^-1 with γ=0.9995 for its dehydrogenation metabolite. The elimination of nimodipine and the formation of dehydrogenation metabolite was linear. CONCLUSION: Nimodipine was rapidly metabolized to its dehydrogenated metabolite in human liver microsomes. Our results showed that human liver CYP450 was involved in the oxidation of dihydropyridine ring of nimodipine.