Determination of captopril in pharmaceutical tablets by anion-exchange HPLC using indirect photometric detection; a study in systematic method development

The development and validation of a significantly cost effective and simpler anion-exchange high performance liquid chromatorgaphic (HPLC) procedure than the compendial methods for the analysis of captopril in tablet dosage forms using indirect photometric detection is described. A low capacity anion-exchange column was used with potassium phthalate as the mobile phase marker and indirect detection at 280 nm. The chromatographic conditions were optimized using the Box and Behnken factorial experimental design. The method was precise and accurate with percent recovery (±%R.S.D.) of 99.8±0.7% ( n =12) with the spiked concentrations ranging between ±30% of the assay level. Youden and Steiner's robustness test, involving seven chosen variables, showed that the method is robust. Using the developed method, commercially available captopril tablets were assayed and the results were found to be comparable with those obtained by the compendial method.