LC-MS/MS法同时测定大鼠血浆中甘草酸和甘草次酸

目的：建立一种同时测定大鼠血浆中甘草酸和其代谢产物甘草次酸的高效液相色谱一串联质谱的（LC-MS／MS）分析方法。方法：采用汉邦VP—ODS（150min×2．1nun，5μm）色谱柱，流动相为甲醇和1％的甲酸水，梯度洗脱：21％水相（0-3．5min），2％水相（3．5-8．2min）。简单的乙腈沉淀蛋白法处理血浆样品。以格列喹酮为内标，采用ESI源负离子模式、多反应检测进行测定。检测离子对分别为m／z821．4→350．9（甘草酸）、m／z526→401．1（格列喹酮）和m／z469．2→425．2（甘草次酸）。结果：甘草酸和甘草次酸的检测浓度分别在50－2000ng·mL-1、10-500ng·mL-1范围内线性关系良好。相关系数为0.9989和0．9981。日内及日间精密度RSD均小于15％。结论：方法专属性强．准确度好．适用于同时监测甘草酸和甘草次酸的浓度及进行药动学研究。

Simultaneous Determination of Glycyrrhizin and Its Major Metabolite Glycyrrhetinic Acid in Rat Plasma by LC-MS/MS

Objective： A sensitive liquid chromatography electrospray ionization-mass spectrometry （LCMS/MS） method was established and validated for the simultaneous determination of glycyrrhizin and its major metabolite glycyrrhetinic acid in rat plasma. Methods： After treatment with acetonitrile to precipitate proteins, plasma samples were analyzed on a reversed-phase Cis （ODS） column with a mobile phase of methanol： 1% formic acid solution. The elution gradient was set as 21% aqueous phase at 0-3.5 min and 2% aqueous phase at 3.5-8.2 min. MS determination was performed using negative electrospry ionization （negative ESI） in the selected ion monitoring mode. A multiple reaction monitoring （MRM） mode was chosen for the detection of m/z 821.4→350.9 （glycyrrhizin）, m/z 526.2→401.1 （gliquidone） and m/z 469.2→425.2 （glycyrrhetinic aid）. Results： The assay of glycyrrhizin was calibrated in the range from 50 to 2000 ng-mL-1 （r2=0.9989）, and glycyrrhetinic aid was calibrated in the range from 10 to 500 ng.mL-1 （r2=0.9981）. The percent coefficient of variation for accuracy and precision （inter-run and intra-run） for this method was less than 15.0%. Conclution： The LC-MS/MS method has passed the validations for specificity, sensitivity, accuracy, precision and calibration function. It is suitable for concentration determination of glycyrrhizin and its major metabolite glycyrrhetinic acid in rat plasma.