HPTLC method development, validation, and stress degradation studies for atorvastatin and ezetimibe in multicomponent tablet dosage form

A simple, precise, rapid, selective, and economic high performance thin-layer chromatography method has been established for simultaneous analysis of atorvastatin (ATV) and ezetimibe (EZE) in tablet dosage forms. The chromatography separation was performed on precoated silica gel 60 GF254 plates with toluene–ethyl acetate–methanol 12:5:3 (v/v/v) as mobile phase. The plate was developed to a distance of 8.0 cm at ambient temperature. The retention factors for ATV and EZE were 0.31 and 0.57, respectively. The detection band was carried out at 254 nm. The calibration curve was linear in the concentration range of 200–1200 ng/spot for both ATV and EZE. For ATV, the recovery study results ranged from 99.44 to 99.54% with RSD value ranging from 0.067 to 0.107%. For EZE, the recovery results ranged from 98.88 to 99.00% with RSD value ranging from 0.154 to 1.756%. The assay was 99.89% for ATV and 99.84% for EZE. The calibration plots revealed a good linear relationship with r2 = 0.9991 for ATV and 0.9992 for EZE. Both ATV and EZE were subjected to different stress conditions—acid, alkaline hydrolysis, oxidation, photo degradation, dry, and wet heat treatment—as prescribed by ICH. The degradation products were well resolved from the pure drug with significantly different Rf values. The method was validated for precision, accuracy, specificity, ruggedness, and robustness.