Determination of metformin in fixed-dose combination tablets by ATR-FTIR spectroscopy

This study describes the determination of metformin in fixed-dose combination (FDC) tablets using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy.  Metformin standard concentrations ranging from 10 to 100% w/w were prepared by diluting with potassium bromide (KBr). Prediction model was developed using partial least squares (PLS) based on the ATR-FTIR spectral region 1066.50–1052.47 cm−1. The results of the model showed good linearity with a regression coefficient (R2) of 0.9997. The root mean square error of calibration (RMSEC) was 0.447. Three commercial FDC drugs containing 500 mg metformin/tablet were quantified. The accuracy of the metformin quantification in the FDC tablets was 100% ± 2. The developed ATR-FTIR method is suitable for the routine determination of metformin in FDC tablets and other pharmaceutical formulations.