DEVELOPMENT AND VALIDATION OF STABILITY-INDICATING SIMULTANEOUS ESTIMATION OF METFORMIN AND ALOGLIPTIN IN TABLETS BY HIGH-PERFORMANCE THIN LAYER CHROMATOGRAPHY
S Malathi, Arunadevi Natarajan
Abstract
Objective: A simple and stability-indicating high-performance thin-layer chromatographic method was developed and validated for the simultaneous estimation of metformin and alogliptin in tablets. Methods: The method was developed in TLC aluminum plates pre-coated with silica gel 60F254 as the stationary phase and the solvent system consists of methanol: chloroform: 0.5% ammonium sulphate [4:4:2, v/v/v]. The system was found to conferred a compact spot for metformin [Rf value of 0.44±0.02] and alogliptin [Rf value of 0.66 ± 0.22]. Densitometric analysis of metformin and alogliptin was carried out at the wavelength of 254 nm. Forced degradation studies were conducted to know the stability of the drug samples under various stress conditions like acid, base, peroxide, photolytic degradation according to the ICH guidelines. Results: The developed method was found to be suitable for the excellent separation of the drug samples. Calibration curves were linear in the range of 40-200 ng/spot with a correlation coefficient of 0.996 for metformin and calibration curves were linear in the range of 1-5 ng/spot with a correlation co-efficient of 0.997 for alogliptin, respectively. Stability study shows that the chromatograms of samples degraded with acid, base, hydrogen peroxide, dry heat, and photolytic showed well-separated spots of pure metformin and alogliptin as well as some additional peaks at different Rf values. The method was successively applied to pharmaceutical formulation. No chromatographic interference from the tablet excipients was found. Conclusion: The newly developed method can be applied for the identification and quantitative determination of metformin and alogliptin in the combined dosage form.