Ion-pair HPLC method for the quantification of metformin in human urine

Abstract

The aim of this study was to develop and validate a selective and sensitive ion-pairing HPLC–UV method for the determination of metformin in human urine using a conventional reversed-phase column. The bioanalytical method was carried out using a RP-C18 column (250×4.0 mm; 5 μm). A mobile phase consisting of acetonitrile and 10 mM sodium phosphate buffer (pH=6.0, 30:70 v/v) and sodium dodecyl sulfate (0.3%) was pumped at an isocratic flow rate of 1.00 mL/minute and quantification was achieved at 236 nm using using a UV/VIS DAD. The calibration curves were linear (r2 >0.999) in the concentration ranges of 62.5–2000 μg/mL for metformin in urine. LOD and LOQ were found to be 12 μg/mL and 35 µg/mL, respectively. The method was found to be rapid, precise and accurate for quantification of metformin in human urine. This method was successfully applied to a pharmacokinetic study of humans through oral administration.