Simultaneous determination of metformin and glimepiride in human serum by ultra high performance liquid chromatography quadrupole time of flight mass spectrometry detection

•UPLC-QTOF/MS determination of glimepiride and metformin in human serum samples.•Limits of detection and quantitation were 0.4 and 1.7 μg·L−1 for metformin.•Limits of detection and quantitation were 0.7 and 3.3 μg·L−1 for glimepiride.•The method was effective for therapeutic monitoring in a short time of analysis. This work proposes a simple method for the simultaneous determination of two antidiabetic compounds, metformin and glimepiride, by ultra-high performance liquid chromatography using quadrupole time of flight mass spectrometry detection with electrospray ionization. The method was validated and shown to be linear, selective, accurate and precise. The chromatographic separation was performed using a BEH C18 column (50 mm x 2.1 mm, 1.7 μm particle size). The mobile phase was composed by 0.05% (v/v) aqueous formic acid solution and acetonitrile using a gradient elution program, at a flow rate of 0.3 mL/min. Linearity range for metformin was 1.7–100 μg·L−1, using propranolol as internal standard and 3.3–100 μg·L-1 for glimepiride using glibenclamide as internal standard. Limits of detection and lower limits of quantitation were 0.4 μg·L-1 and 1.7 μg·L-1 for metformin and 0.7 and 3.3 μg·L-1 for glimepiride, respectively. The method was used for the simultaneous determination of these compounds in human serum samples with lower limits of detection and quantitation than serum levels reported in previous works that allows its applicability in therapy drug monitoring.