Determination of the antihyperlipidemic simvastatin by various voltammetric techniques in tablets and serum samples.

The electrochemical behavior and determination of simvastatin (SMV), a lipid-lowering drug, were studied in aqueous alcohol medium at a stationary glassy carbon electrode. Cyclic voltammetry studies showed one main, well-defined, sharp oxidation peak between pH 2 and 8. The oxidation was irreversible and exhibited a diffusion controlled mechanism. Differential pulse and square wave voltammetric methods for the quantitative determination of SMV in pharmaceutical dosage forms and spiked serum samples were developed based on the linear relationship between the peak current and the concentration. Differential pulse and square wave voltammetric techniques for the determination of SMV in 0.1 M H2SO4 and a constant amount of methanol (20%), which allow quantitation over the 2 x 10(-6)-1 x 10(-4) M range in supporting electrolyte with a detection limit of 2.71 x 10(-7) M and 5.50 x 10(-7) M for differential pulse and square wave voltammetric methods, respectively, are proposed. The repeatability and reproducibility of the methods were determined. Precision and accuracy were also checked. These methods were used for the determination of SMV in tablets. The standard addition method was used in biological media. No electroactive interferences from endogenous substances and excipients were found in biological fluids and pharmaceutical dosage forms, respectively.