Stability Indicating RP-HPLC Method for Simultaneous Determination of Atorvastatin and Nicotinic Acid from Their Combined Dosage Form

Krishna R. Gupta, Sonali S. Askarkar, Sudhir G. Wadodkar

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Atorvastatin; Nicotinic acid; Rp-HPLC; stability indicating; tablets


The study describes development and subsequent validation of a stability indicating reverse-phase HPLC method for simultaneous estimation of atorvastatin (ATR) and nicotinic acid (NTA) from their combined dosage form. The proposed RP-HPLC method utilizes a Phenomenex® C18, 5 μm, 250 mm X 4.6 mm i.d. column, at ambient temperature, optimum mobile phase consisted of acetonitrile and 50mM potassium dihydrogen phosphate buffer (68:32, v/v), apparent pH adjusted to 4.5±0.1 with phosphoric acid solution, effluent flow rate monitored at 0.8 mL min-1, and UV detection at 247 nm. The combination drug product are exposed to thermal, acid/base hydrolytic, humidity and oxidative stress conditions, and the stressed samples were analyzed by proposed method. The described method is linear over the range of 2-10 μg mL-1 and 20-100 μg mL-1 for ATR and NTA, respectively. The mean recoveries are 100.99 and 102.65% for ATR and NTA, respectively. The intermediate precision data obtained under different experimental setup, the calculated value of coefficient of variation (CV,%) is found to be less than critical value. The limit of detection for ATR and NTA are found to be 0.16 and 0.12 μg mL-1, respectively. Chromatographic peak purity data of ATR and NTA indicated no co-eluting peaks with the main peaks of drugs which demonstrated the specificity of assay method for their estimation in presence of degradation products. The proposed method can be useful in the quality control of combination drug products.