INVESTIGATION OF GREEN UV SPECTROPHOTOMETRIC TECHNIQUES FOR SIMULTANEOUS ESTIMATION OF SELECTED FIXED-DOSE COMBINATION

The binary mixture of Linagliptin (LINA) with Empagliflozin (EMPA) in fixed dose combination was selected with the aim to develop and rigorously validate simple yet reliable UV spectrophotometric methods which are specific, precise and accurate for their simultaneous quantification. Two UV spectrophotometric methods, namely Ratio Subtraction and Extended Ratio Subtraction (RS-ERS) and Ratio Subtraction Coupled with Constant Multiplication (RS-CM) methods, were developed. In RS-ERS, LINA and EMPA were accurately determined at 294 nm and 273 nm, respectively, taking divisor concentrations of 10 µg/mL for LINA and 20 µg/mL for EMPA. The linearity found to be in the range of 6-14 µg/mL for LINA and 12-28 µg/mL for EMPA with regression equations y = 0.0435x – 0.0137 (r2 = 0.9994) and y = 0.0026x + 0.0087 (r2 = 0.9997) respectively. Precision studies demonstrated satisfactory repeatability with% RSD values ranging from 1.12 – 1.96%. Accuracy assessed by recovery studies at 80%, 100%, and 120% levels showed recoveries of 100.19 – 101.33% for RS-ERS and 99.94-101.59% for RS-CM. Assay results for the marketed formulation were within pharmacopeial limits, ranging from 98.73-101.43% of the label claim. Robustness studies involving deliberate variations in wavelength, divisor conc. and constant region selection showed %RSD values below 2%, indicating the reliability of the methods. Greenness assessment using AGREE and ComplexGAPI tools yielded an AGREE score of 0.82 and an E-factor of 0.2, indicating favourable environmental characteristics. The developed methods were validated as per ICH Q2(R2) guidelines and were found to be accurate, precise, robust, economical and suitable for routine quality control analysis of Linagliptin and Empagliflozin in combined dosage forms.