STABILITY-INDICATING LIQUID CHROMATOGRAPHIC METHOD FOR THE SIMULTANEOUS DETERMINATION OF ASCORBIC ACID, CITRIC ACID, BUTYLATED HYDROXYANISOLE, SIMVASTATIN AND RELATED COMPOUNDS IN PHARMACEUTICAL SOLID

A Simple, fast and perceptive method has been developed and validated for the determination of simvastatin (SIM), its potential impurities in tablet formulations including its preservatives and stabilizer viz. Ascorbic Acid (AA), Citric Acid (CAM) and Butylated hydroxyanisole (BHA). A competent chromatographic separation was achieved on a Zorbax SB CN column with a mobile phase combination containing a isocratic elution at a flow rate of 1.5 mL/ min and quantification was carried out using ultraviolet detection at 205 nm with an ambient column temperature. The resolution among Ascorbic Acid & Citric Acid, BHA and SIM Imp-1 was found greater than 2.0. Regression analysis shows an r value (correlation coefficient) greater than 0.999. This method was capable to detect all the process impurities of simvastatin, at a level below 0.05% with respect to a test concentration of SIM (1.6 mg/mL). %RSD for the inter-day and intra-day precisions for the preservative components (AA, CAM & BHA) and impurities (imp-1 & imp-2) of SIM were found < 2.0. The drugs were subjected to stress conditions of acid, base, water hydrolysis, oxidation, photolysis, humidity and thermal degradation, as prescribed by International conference on harmonization (ICH).