Determination of Metformin in Human Plasma by Liquid Chromatography-tandem Mass Spectrometric Assay

Introduction Metformin (1,1-dimethylbiguanide) (Fig. 1) is an oral anti-hyperglycemic agent used in the treatment of non-insulin-dependent diabetes mellitus (type Ⅱ). Owing to its weight-decreasing and serum lipid-normalizing effects, it is especially recommended for obese patients1,2] Various analytical methods have been described for the measurement of metformin in biological fluids, including gas chromatography(GC)3-5], capillary electrophoresis (CE)6] and HPLC7～16]with UV detection7-12,17] HPLC-Mass spectrometry (LC/APCIMS/MS ) offers an attractive alternative to HPLC18].