Alogliptin Benzoate/Metformin Hydrochloride

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.

A guide experimental design in chromatographic method development was described and applied successfully to the analysis of different recently approved anti-diabetic pharmaceutical combinations. Enhancement of UHPLC analysis of alogliptin benzoate either with pioglitazone hydrochloride or with metformin hydrochloride was achieved. The optimal chromatographic conditions were not attained by trial and error that requires a large number of experiments. Alternatively, a computer program was used as a systematic optimization strategy for the design of the experiment which accurately predicts the combined effect of different factors simultaneously. Resolution between peaks was studied by the proposed fractional factorial design approach performed by the Minitab® Program using screening and optimization steps. Application of the central composite design was implemented. A Pareto chart was used to exclude the insignificant variables. Linearity ranges were found to be 0.5-40 μg ml-1, 1-20 μg ml-1 and 1-32 μg ml-1 for alogliptin benzoate, pioglitazone hydrochloride and metformin hydrochloride, respectively. The proposed method is applicable for the analysis of six pharmaceutical dosage forms namely, Nesina®, Actos®, Glucophage®, Oseni®, Kazano® and Actoplus MET® tablets.