液相色谱-串联质谱法测定人血浆中的米氮平及在药动学中的应用

目的:研究液相色谱-串联质谱法测定人血浆中的米氮平,并应用于生物等效性研究。方法:50μL 血浆样品经乙腈沉淀蛋白处理后,以乙腈-水-甲酸(80:20:0．2)为流动相,Zorbax SB-C_8柱分离,采用电喷零离子源,选择反应监测方式进行正离子检测。用于定量分析的离子反应分别为m／z 266→195(米氮平)和 m／z 256→167(内标,苯海拉明)。药动学参数采用非室模型计算。结果:米氮平测定方法的线性范围为0．18- 144．0 μg·L~(-1),定量下限为0．18 μg·L~(-1)。日内、日间精密度(RSD)均小于6．2％,准确度(RE)在±2．0％以内。每个样品测试时间仅为3．5 min。口服米氮平片30 mg后测得参比制剂和受试制剂的t_(max)分别为(1．4±s 0．7)h 和(1．4±0．7)h,c_(max)分别为(65±35)μg·L_(-1)和(69±35)μg·L_(-1),t_(1/2)分别为(24±6)h和(24±6)h,用梯形法计算,AUC_(0-96)分别为(814±419)μg·h·L_(-1)和(842±387)μg·h·L_(-1)。以AUC_(0-96)计算,受试制剂相对生物利用度为(102±18)％。结论:该法选择性强、灵敏度高、操作简便,适用于米氮平的制剂的生物等效性评价及临床药动学研究。

Determination of mirtazapine in human plasma with LC/MS/MS method and application in pharmacokinetic study

AIM:To develop a rapid,sensitive and specific LC/MS/MS method for direct determination of mirtazapine in human plasma and to study the bioequivalence of different formulations containing mirtazapine. METHODS:The plasma concentration of mirtazapine was determined with an aliquot of 50μL plasma treated by precipitation. The analytes of interest were separated on a Zorbax SB-C_8 column with the mobile phase consisting of acetonitrile-water-formic acid (80:20:0.2). A Finnigan TSQ Ultra tandem mass spectrometer equipped with electrospray ionization source was used as detector and operated in the positive ion mode. Each plasma sample was chromatographed within 3.5 min. RESULTS:The linear calibration curves were obtained in the concentration range of 0.18-144.0μg·L~(-1). The lower limit of quantification was 0.18 μg·L~(-1). The intra- and inter-day relative standard deviation (RSD) across three validation runs over the entire concentration range was less than 6.2 %. Accuracy determined at three concentrations(0.36, 7.20 and 115.2 μg·L~(-1) for mirtazapine) ranged from 100.6 ％ to 102.0 %.Pharmacokinetic parameters of mirtazapine reference formulation was obtained as follows:t_(max) mwas( 1.4 ±s 0.7) h, c_(max) was (65± 35)μg·L~(-1), t_(l/2) was (24± 6) h, AUC_(0-96) was (814± 419) μg·h·L~(-1), pharmacokinetic parameters of mirtazapine test formulation were obtained as follows: t_(max) was (1.4 ± 0.7) h,c_(max) was(69±35) μg·L~(-1), /,2was (24 ±6) h,AUC_(0-96) was (842±387) μg·h·L~(-1). Calculated with AUC_(0-96), the bioavailability of two formulations was(102 ±18) %. CONCLUSION :LC/MS/MS method is sensitive, convenient and proved to be suitable for bioequivalence evaluation of different formulations containing mirtazapine and also for clinical investigation of mirtazapine pharmacokinetics.