Capillary Electrophoresis: MEKC assay method for simultaneous determination of olmesartan medoxomil, amlodipine besylate and hydrochlorothiazide in tablets

Objectives: A simple, fast, accurate and precise micellar electrokinetic chromatographic (MEKC) method was developed and validated for the simultaneous quantification of olmesartan medoxomil (OLM), amlodipine besylate (AMB) and hydrochlorothiazide (HCT) in tablets. Methodology: The analytes were separated and quantified on untreated fused silica capillary with the help of background electrolyte comprising of 40 mM phosphate buffer, 20 mM sodium dodecyl sulphate (pH 6.0) and acetonitrile (90%:10% v/v). Losartan was selected as an internal standard and the detector was adjusted at 220 nm. The concentration of buffer and SDS, pH of buffer, the organic modifier, injection time, temperature and the voltage applied were optimized. The developed method was validated according to ICH guidelines. Results: The method demonstrated wide linearity ranges of 2-80 µg/ml, 1-40 µg/ml and 5-200 µg/ml with LODs of 1.25 µg/mL, 0.44 µg/mL and 3.81 µg/mL for OLM, AMB and HCT respectively. Furthermore, the intra day and inter day repeatability was well within the acceptable range. From the formulation, the mean recoveries of HCT, OLM, and AMB were found to be 99.8%, 99.1% and 100.11% respectively. Conclusion: Finally, the MEKC method was effectively applied for the assay of HCT, OLM, and AMB from their formulation and results were compared with the reported RP-HPLC method. In terms of precision and accuracy, no significant difference was observed in the outcomes of both the methods.