This study was conducted to develop a highly selective, sensitive, and validated method for quantifying metronidazole in human plasma and bile fluid. Metronidazole and metronidazole-d4 (internal standard) were extracted from 100 μL of plasma and bile fluid by liquid-liquid extraction. Liquid chromatography with a Hydrosphere C18 column (50 × 2.0 mm) was performed using 10 mM ammonium formate (pH 4.0) and acetonitrile (20:80, v/v) as the mobile phase. Triple quadrupole mass spectrometry was operated with an electrospray ionization interface in multiple reaction monitoring and positive ion modes. The calibration curves were linear for bile and plasma samples over the range of 50 to 20000 ng/mL (r² > 0.999). The intra- and inter-day coefficients of variation (CVs) for plasma ranged from 2.50% to 7.85% and 3.11% to 16.9%, respectively; for bile, the intra-and inter-run precision (CVs) ranged from 2.76% to 13.2% and 3.16% to 11.5%, respectively. The mean extraction recovery for metronidazole ranged from 76.5% to 82.1% in plasma and from 78.8% to 87.8% in bile, respectively. Our proposed analytical method was successfully applied to determine metronidazole concentrations in bile as well as in plasma at multiple time points in a patient with acute cholangitis.

进行这项研究是为了开发一种高度选择性，灵敏且经过验证的定量人体血浆和胆汁中甲硝唑的方法。甲硝唑和甲硝唑-d4（内标）通过液-液萃取从100μL血浆和胆汁中萃取。使用10 mM甲酸铵（pH 4.0）和乙腈（20:80，v / v）作为流动相，使用Hydrosphere C18柱（50×2.0 mm）进行液相色谱分析。三重四极杆质谱通过电喷雾电离界面在多个反应监测和正离子模式下运行。胆汁和血浆样品在50至20000 ng / mL（r ²> 0.999）。血浆的日内和日间变异系数（CVs）分别为2.50％至7.85％和3.11％至16.9％。对于胆汁，运行内和运行间精度（CV）分别为2.76％至13.2％和3.16％至11.5％。血浆中甲硝唑的平均提取回收率范围为76.5％至82.1％，胆汁为78.8％至87.8％。我们提出的分析方法已成功应用于在急性胆管炎患者的多个时间点测定胆汁和血浆中甲硝唑的浓度。