Simultaneous determination of 14 oral antihyperglycaemic drugs in human urine by liquid chromatography-tandem mass spectrometry.

A simple, sensitive, and rapid assay based on hydrophilic interaction liquid chromatography (HILIC) with tandem mass spectrometry was developed and validated for the simultaneous determination of metformin and 13 other oral antihyperglycaemic drugs in human urine using metoprolol as an internal standard. A simple sample clean-up procedure using the "dilute and shoot" approach enabled fast and reliable analysis. Chromatographic separation was performed on a HILIC column using an elution gradient of mobile phase A, composed of 1 mM ammonium formate (pH 5), and mobile phase B, composed of acetonitrile, at a flow rate of 0.35 mL/min. Quantitation was performed on a triple quadrupole mass spectrometer operated in multiple reaction monitoring mode by using electrospray ionization in positive ion mode. The total chromatographic run time was 20 min. Calibration curves for each analyte were linear over concentration ranges of 2-300, 5-400, or 20-500 ng/mL, with a coefficient of determination above 0.99. The method was validated for selectivity, sensitivity, recovery, linearity, accuracy and precision, system suitability, robustness, and stability. Inter-batch and intra-batch coefficients of variation across four validation runs were ≤ 13.62%. The present method was successfully applied for the analysis of metformin and nateglinide in urine samples after their oral administration to healthy human subjects under fasted conditions.