Voltammetric determination of tolcapone in pharmaceutical and human serum samples using carbon paste electrode

The electrochemical behaviour of Pioglitazone (PGZ) drug was studied using carbon paste electrode (CPE) in Britton Robinson (BR) buffer solution. Here Cyclic voltammetry and differential pulse voltammetric techniques were employed for this determination. The reduction process was shown to be irreversible over the pH range (2.0–10.0) and the well-defined reduction peaks are obtained at -1.80V based on diffusion controlled. Effects of cathodic peak potential, current ( I pa ), scan rate, pH, etc., have been discussed. A possible electro reduction mechanism was proposed. An analytical method was developed for the determination of pioglitazone in BR buffer solution at pH 6.0 as a supporting electrolyte. The cathodic peak current varied linearly with pioglitazone concentration in the range 6.25×10 −5 M to 3.25×10 −3 M with a limit of detection (LOD) of 2.65 × 10 −10 M and limit of quantification (LOQ) of 4.52 × 10 −8 M. The proposed method was successfully applied to the determination of pioglitazone in pharmaceutical and human urine samples.