Validation of different spectrophotometric methods for determination of vildagliptin and metformin in binary mixture

•The proposed methods can be used in QC without the difficulties of HPLC.•The proposed methods can be adopted for further work with degradation products.•The proposed methods were validated according to ICH guidelines.•The proposed methods have been applied successfully on the dosage form.

New, simple, specific, accurate, precise and reproducible spectrophotometric methods have been developed and subsequently validated for determination of vildagliptin (VLG) and metformin (MET) in binary mixture. Zero order spectrophotometric method was the first method used for determination of MET in the range of 2–12 μg mL−1 by measuring the absorbance at 237.6 nm. The second method was derivative spectrophotometric technique; utilized for determination of MET at 247.4 nm, in the range of 1–12 μg mL−1. Derivative ratio spectrophotometric method was the third technique; used for determination of VLG in the range of 4–24 μg mL−1 at 265.8 nm. Fourth and fifth methods adopted for determination of VLG in the range of 4–24 μg mL−1; were ratio subtraction and mean centering spectrophotometric methods, respectively. All the results were statistically compared with the reported methods, using one-way analysis of variance (ANOVA). The developed methods were satisfactorily applied to analysis of the investigated drugs and proved to be specific and accurate for quality control of them in pharmaceutical dosage forms.

Graphical abstractLeft: Zero order spectra of metformin (2–10 μg/ml) () and vildagliptin (4–20 μg/ml) (-----) in methanol. Right: First derivative spectra of metformin (2–10 μg/ml) (—) and vildagliptin (4–20 μg/ml) (-----) in methanol.Figure optionsDownload full-size imageDownload as PowerPoint slide