Development of a Stability-Indicating HPLC Method for Simultaneous Determination of Amlodipine Besylate and Atorvastatin Calcium in Tablets

The fixed dose combination which contains the antihypertensive agent Amlodipine and the statin, Atorvastatin is the first combination of its kind designed to treat two risk factors for cardiovascular disease (CVD). A Validated HPLC method was developed as a Stability-Indicating HPLC Method for both drugs and four of their impurities. The method was performed on Phenomenex kinetex C18 100A (250x4.6 mm, 2.6μ) and the mobile phase consisted of Potassium dihydrogen phosphate (pH 5.5, 0.03M) - Acetonitrile (65:35 V/V) which pumped at a flow rate 1.2 ml/min at 40°C. 20 μl of drugs sample solutions were monitored at wavelength 240 nm. The proposed method was validated in terms of linearity ranged between [(5.18-15.54 and 5.26-15.78 μg/ml) corresponding levels of 50-150% w/w of the nominal analytical concentration] with linear regression equations were [{y = 44667X - 405.02 (r= 0.9999) and Y = 41443X - 2251.4 (r= 0.9999)], accuracy [99.73± 0.46 and 100.22±1.04 %], precision [100.34± 0.61 and 101.01± 1.72 %], limits of detection [0.16 and 0.17 μg/ml] and limits of quantitation [0.48 and 0.52 μg/ml] for Amlodipine besylate and Atorvastatin calcium respectively. Amlodipine Besylate, Atorvastatin Calcium and Caduet tablets bulk powders were stressed under different conditions in forced degradation studies. Method validation was developed following the recommendations for analytical method validation of International Conference on Harmonization (ICH) and Food and Drug administration (FDA) organizations.