RP-HPLC method for simultaneous estimation of Candesartan and Amlodipine in bulk and pharmaceutical dosage forms

A simple, rapid, accurate and precise isocratic reversed phase high performance liquid chromatographic method has been developed and validated for simultaneous estimation of Candesartan and Amlodipine in tablet dosage forms. The chromatographic separation was carried out on C18 analytical column (150 mm x 4.6 mm I.D., 5 µm particle size) with a mixture of phosphate buffer pH 6.8 was adjusted with potassium hydroxide and acetonitrile in the ratio of 35:65 V/V as a mobile phase at a flow rate of 1.0 mL/min. UV detection was performed at 238 nm. The retention times were 3.610 minutes and 4.773 minutes for Candesartan and Amlodipine respectively. Calibration plots were linear (r 2 =0.999 for Candesartan and 1 for Amlodipine) over the concentration range of 4-24 µg/mL for Candesartan and 2.5-15 µg/mL for Amlodipine. The method was validated for linearity, precision, accuracy, ruggedness and robustness. The proposed method was successfully used for simultaneous estimation of Candesartan and Amlodipine in tablet dosage forms. Validation studies revealed that method is specific, rapid, reliable and reproducible. The high % recovery and low % RSD confirms the suitability of the proposed method for routine quality control analysis of Candesartan and Amlodipine in bulk and tablet dosage forms.