Electrochemical behaviour and voltammetric determination of rosuvastatin calcium in pharmaceutical preparations using a square-wave voltammetric method

In this study, the electrochemical behaviour of rosuvastatin calcium, which is a hydroxy methyl glutaryl Co-A inhibitor (a member of the statin group), used for the treatment of hypercholesterolemia and dyslipidemia was investigated using cyclic voltammetry (CV) and chronoamperometry (CA) methods. According to these studies it is assumed that the reaction is a diffusion-controlled process and irreversible. The results from the CA were calculated using Cottrell's equation and the diffusion coefficient was found to be 5.79 x 10(-5) +/- 0.22 x 10(-5) cm(2) s(-1). It was calculated that 2 electrons were transferred. For the determination of rosuvastatin calcium from the pharmaceutical preparations, a square wave voltammetry (SWV) method was selected and developed because it is more sensitive and faster than the other voltammetric methods. Rosuvastatin calcium's reduction peak was seen at -1184 mV in pH 5 acetate buffer with a hanging mercury drop electrode (HMDE) used as the working electrode, an Ag/AgCl with saturated 3 M KCl reference electrode and a platinum wire counter electrode. 70 Hz frequency, 4 mV scan increment and 25 mV pulse amplitude were chosen as optimum parameters. This method was validated according to the ICH guidelines on analytical method validation processes. Linearity for rosuvastatin calcium was found between 0.20 and 10.00 mu g mL(-1). While the limit of detection for rosuvastatin calcium was 0.07 mu g mL(-1), the limit of quantitation was 0.20 mu g mL(-1). As a result of these validation studies, the selective, accurate and precise square wave voltammetric method, which gives sensitive and repeatable results, was applied to the determination of rosuvastatin calcium from pharmaceutical preparations. The results obtained from the developed method were compared with a spectrophotometric method and a capillary electrophoresis method reported in the literature and no significant difference was found statistically.