Simple and rapid method determination for metformin in human plasma using high performance liquid chromatography tandem mass spectrometry: Application to pharmacokinetic studies

A rapid and simple method for quantitation of metformin (MET) in human plasma by HPLC–MS/MS was developed and validated. The sample preparation consists of plasma deproteinization using acetonitrile. The mobile phase consisted of water–acetonitrile and formic acid (55/45/0.048, v/v/%) and the run time was 3 min. A pursuit C18 (100 mm × 2.0 mm i.d., 3 μm) column connected to a guard column MS-pursuit (0.20 mm × 0.20 mm i.d., 5 μm) was used. The range of the calibration curve was from 20 to 5000 ng/mL, the limit of quantitation being 20 ng/mL. The detection was performed on a mass spectrometer (ESI+), using metoprolol as internal standard. The calibration curves have r2 values of 0.995 (CV = 0.24%, n = 10). The accuracy and precision were between 90.74 and 106.7% and coefficients of variations (CV) of 1.10 and 4.35%, respectively. The method was applied to determine the pharmacokinetic parameters: Cmax (1667.25 ng/mL) and Tmax (3.89 h).