Comparative study between UHPLC-UV and UPLC-MS/MS methods for determination of alogliptin and metformin in their pharmaceutical combination.

A new UPLC-MS/MS method (method A), for simultaneous determination of alogliptin (ALN) and metformin (MET) in their recently approved pharmaceutical combination Kazano® tablets, was developed and compared to a new UHPLC-UV method (method B). Concerning method A, separation was achieved on Hypersil gold 50 mm × 2.1 mm (1.9 μm) column, using acetonitrile and 0.2 % formic acid aqueous solution as the mobile phase with a gradient elution. Electrospray ionization (ESI) source was operated in positive ion mode. Selected reaction monitoring (SRM) mode on a triple quadropole mass spectrometer was used to quantify the drugs utilizing the transitions of 340.33 → 116.32 (m/z) and 130.12 → 71.32 (m/z) for ALN and MET, respectively. Concerning chromatographic separation using UV detection in method B, it was achieved on a Symmetry® C18 column 100 mm × 2.1 mm (2.2 μm) applying an isocratic elution based on methanol - water (10:90, v/v) at pH 3 as a mobile phase. The photodiode array detector was operated at 210 nm. Method A showed good linearity over the concentration ranges of 5-400 ng mL-1 and 25-2000 ng mL-1 for ALN and MET, respectively, while method B showed satisfactory results using ranges of 0.25-8 μg mL-1 and 5-50 μg mL-1 for ALN and MET, respectively. The optimized validated methods are suitable for QC labs but the UPLC-MS/MS method offered the advantage of shorter analytical times and higher sensitivity and selectivity.