DEVELOPMENT AND VALIDATION OF RP-UPLC METHOD USING EXPERIMENTAL DESIGN APPROACH FOR SIMULTANEOUS ESTIMATION OF CANDESARTAN CILEXETIL AND CHLORTHALIDONE

Candesartan Cilexetil is an antihypertensive agent currently available in combination with Hydrochlorothiazide. However, it has been proven by research that half dose of Chlorthalidone is equipotent to the dose of Hydrochlorothiazide in similar combination with Candesartan Cilexetil. At present there is no Liquid Chromatographic (LC) method available for the simultaneous estimation of Candesartan Cilexetil and Chlorthalidone in pharmaceutical dosage form. A simple, rapid, reliable and robust reversed phase ultra-performance liquid Chromatography (RP-UPLC) method was developed as per International Conference on Harmonization (ICH) guidelines. The best separation was achieved in less than 5 minutes on a 50 × 2.1 mm, 2.2 µm particle size Dionex C18 column with the gradient mobile phase 5 mM, 6.2 ± 0.5 pH ammonium acetate buffer - acetonitrile at a flow rate of 0.5 mL/min at 215nm. The detector response was linear in the range of 10-200 ppm of these drugs. LOD obtained was 3.04 ppm for Candesartan Cilexetil, 2.82 ppm for Chlorthalidone. Further evaluation of robustness of this method was carried out using Plackett-Burman verification with four factors two levels (high & low) within analytical QbD-principles using statistical software. The outcome of normal probability and overall desirability plots were found acceptable.