Simultaneous determination of metformin and glipizide in human plasma by liquid chromatography-tandem mass spectrometry

A method has been developed for the simultaneous quantification of metformin (I) and glipizide (II) in human plasma. It is based on high-performance liquid chromatography with electrospray ionization tandem mass (LC-ESI-MS/MS) spectrometric detection in positive ionization mode. Phenformin (III) and gliclazide (IV) were used as internal standards for I and II, respectively. The MS/MS detection was performed in multiple reaction monitoring (MRM) mode. The precursor-product ion combinations of m/z 130 -> 71, 446 -> 321, 206 -> 60 and 324 -> 127 were used to quantify I, II, III and IV, respectively. This method was validated in the concentration ranges of 0.02-4 mu g/mL for I and 0.004-0.8 mu g/mL for II. It was utilized to support a clinical pharmacokinetic study after single dose oral administration of a combination of I and II. Copyright (c) 2007 John Wiley & Sons, Ltd.