Simultaneous estimation of atorvastatin calcium and aspirin in combined dosage form by liquid chromatographic method

Abstract

Summary An isocratic reversed-phase liquid chromatograpic assay method was developed for the quantitative determination of atorvastatin and aspirin (ASP) in combined dosage form. A Phenomenex Gemini C-18, 5-μm column with mobile phase containing 0.02 M potassium dihydrogen phosphate-acetonitrile-methanol (30:30:40, v/v/v) adjusted to pH 3 using o-phosphoric acid was used. The flow rate was 1.0 mL min−1 and effluents were monitored at 240 nm. The retention times (RTs) of atorvastatin calcium (ATV) and ASP were 10.5 and 3.8 min, respectively. ATV and ASP stock solutions were subjected to acid and alkali hydrolysis, chemical oxidation, and dry heat degradation. The degraded product peaks were well resolved from the pure drug peak with significant difference in their RT values. Stressed samples were assayed using developed LC method. The proposed method was validated with respect to linearity, accuracy, precision, and robustness. The method was successfully applied to the estimation of ATV and ASP in combined...