A guide for using experimental design in chromatographic method development: applied to the analysis of selected anti-diabetic pharmaceutical combinations.

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.