Voltammetric determination of candesartan cilexetil in its Cu(II) complex and application to pharmaceutical formulations.

The aim of this study was to develop a new, simple, rapid, and sensitive square-wave adsorptive stripping voltammetric method for the determination of candesartan cilexetil in bulk form and pharmaceutical formulations by complex formation with Cu(II). The experimental and instrumental parameters affecting the response of the candesartan cilexetil-Cu(II) complex were investigated and optimized. This method was based on electrochemical reduction of candesartan cilexetil-Cu(II) complex at a hanging mercury drop electrode in phosphate buffer at pH 3.0 containing CuCl2 x 2H2O. A well-defined reduction peak was observed at -325 mV with 30 s accumulation time and -150 mV accumulation potential versus an Ag/AgCl reference electrode in the proposed method. The developed voltammetric method was validated in terms of linearity, sensitivity, precision, accuracy, recovery, selectivity, robustness, and ruggedness. The linear calibration range was 0.50-1.77 microg/mL (r = 0.9972). The LOD and LOQ of this method were 0.10 and 0.50 microg/mL (n = 7), respectively. The developed method was fully validated and applied to the pharmaceutical formulations, including candesartan cilexetil.