Development and ICH Validation of an RP-HPLC Method for Simultaneous Determination of Azilsartan HCl and Chlorthalidone in Pharmaceutical Preparations

AbstractA simple, rapid, accurate, and precise reverse-phase high-performance liquid chromatographic(RP-HPLC) method was developed and validated for the simultaneous estimation of AzilsartanHCl and Chlorthalidone in bulk drugs and pharmaceutical dosage forms. Chromatographicseparation was achieved using a C18 column (250 × 4.6 mm, 5 μm) with a mobile phaseconsisting of acetonitrile and 0.05% orthophosphoric acid (pH 6.5 adjusted with 0.1%triethylamine) in the ratio of 80:20 (v/v) at a flow rate of 1.0 mL/min. Detection was carried outat 256 nm. The retention times of Chlorthalidone and Azilsartan HCl were found to be 3.045 minand 5.701 min, respectively. The method exhibited excellent linearity over concentration rangesof 5–30 μg/mL for Chlorthalidone and 10–60 μg/mL for Azilsartan HCl, with correlationcoefficients greater than 0.999. The developed method was validated according to ICHguidelines and demonstrated satisfactory accuracy, precision, specificity, robustness, andsensitivity. Recovery values ranged from 99.52% to 100.99%, while %RSD values for precisionstudies were below 2%. The limits of detection and quantification were found to be 0.66 and1.84 μg/mL for Azilsartan HCl and 2.11 and 6.40 μg/mL for Chlorthalidone, respectively. Theproposed method was successfully applied to the assay of marketed tablet formulations, yieldingresults within acceptable limits.Azilsartan HCl, Chlorthalidone, RP-HPLC, Method Validation, ICH Guidelines,Simultaneous Estimation.