ATR-FTIR coupled with chemometrics for quantification of vildagliptin and metformin in pharmaceutical combinations having diverged concentration ranges

[Display omitted] •A method for analysis of drug combinations with wide variation in concentration ranges.•ATR-FTIR coupled with PLSR was utilized for simultaneous analysis of vildagliptin and metformin mixtures.•Different concentration ratios (50/500, 50/850 and 50/1000 mg) were analyzed in their combination tablets.•The developed method overcame the problem of limited linearity range of UV-VIS methods in determination of such combinations.•It can be applied for quality control of pharmaceutical dosage forms. An accurate, fast and simple quantitative analysis of drug combinations with wide variation in concentration ranges has been an area of interest for several decades. The limited linearity range of UV-VIS spectroscopy may be insufficient to occupy with multiple components with diverge concentrations and several preparation steps may be required. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) in combination with partial least square regression (PLSR) chemometric method can be a good alternative. Vildagliptin and metformin pharmaceutical dosage forms, which have a wide concentration ranges of (50/500, 50/850 and 50/1000 mg), were used as a model. A calibration set with partial factorial design was used to develop PLSR model able to predict the concentration of unknown samples containing the two drugs. The method was optimized, validated and successfully applied for simultaneous estimation of vildagliptin and metformin in pharmaceutical formulations with high accuracy and reproducibility. The proposed FTIR method was compared to traditional methods such as UV spectroscopy and HPLC to highlight the opportunities and challenges for every technique.