Koseki Nozomu, Kawashita Hiroto, Niina Miyuki, Nagae Yusuke, Masuda Naoki
Drug Metabolism and Pharmacokinetics, Tsukuba Research Institute, Novartis Pharma KK, Ohkubo 8, Tsukuba-shi, Ibaraki 300-2611, Japan.
J Pharm Biomed Anal. 2005 Jan 4;36(5):1063-72. doi: 10.1016/j.jpba.2004.09.007.
An assay based on cation exchange solid-phase extraction and liquid chromatography-tandem mass spectrometry (LC/MS/MS) has been developed for the quantitative determination of metformin in human plasma. The analytical method consists of cation exchange solid-phase extraction (VersaPlate CBA) without any further evaporation/dissolution steps and cation exchange-based HPLC separation (Capcell Pak SCX column) with a normal-phase gradient system followed by semi-micro LC/MS/MS in positive ion selected reaction monitoring mode using electrospray ionization. The method exhibited excellent performance in terms of selectivity, robustness, short run time (7 min/sample) and simplicity of sample preparation. The calibration range was 10-1000 ng/ml with 0.2 ml of plasma. Intra- and inter-day mean accuracies were within the ranges of 100.3-105.0% and 101.2-105.3%, respectively. Intra- and inter-day precisions were within the ranges of 0.8-1.9% and 1.5-8.6%, respectively. Mean absolute recovery was 67.0% for metformin. No apparent loss of metformin after extraction was observed in an autosampler at 10 degrees C for 24 h. Dilution of metformin by blank human plasma up to 20-fold was tested and revealed no impact on the results of determination. Furthermore, the method exhibited high selectivity, since no effect on metformin analysis was observed on comparison of samples with or without nateglinide and other agents in plasma. Results obtained with the method were also comparable to a published LC-UV method on cross-validation. This method can be applied to various clinical pharmacokinetic studies of metformin.
已开发出一种基于阳离子交换固相萃取和液相色谱 - 串联质谱法（LC/MS/MS）的检测方法，用于定量测定人血浆中的二甲双胍。该分析方法包括无需进一步蒸发/溶解步骤的阳离子交换固相萃取（VersaPlate CBA），以及基于阳离子交换的HPLC分离（Capcell Pak SCX柱），采用正相梯度系统，随后在正离子选择反应监测模式下使用电喷雾电离进行半微LC/MS/MS分析。该方法在选择性、稳健性、运行时间短（7分钟/样品）和样品制备简便性方面表现出色。以0.2 ml血浆为样本，校准范围为10 - 1000 ng/ml。日内和日间平均准确度分别在100.3 - 105.0%和101.2 - 105.3%范围内。日内和日间精密度分别在0.8 - 1.9%和1.5 - 8.6%范围内。二甲双胍的平均绝对回收率为67.0%。在10℃自动进样器中放置24小时后，未观察到二甲双胍在萃取后有明显损失。测试了用空白人血浆将二甲双胍稀释至20倍，结果表明对测定结果无影响。此外，该方法具有高选择性，因为在比较血浆中有无那格列奈及其他药物的样品时，未观察到对二甲双胍分析有影响。交叉验证时，该方法所得结果与已发表的LC - UV方法也具有可比性。此方法可应用于二甲双胍的各种临床药代动力学研究。
