Electrochemical Determination of Cardiovascular Drug Cilnidipine at Glassy Carbon Electrode in Pharmaceutical Formulations

Electrochemical behaviour of cilnidipine at glassy carbon electrode was investigated using cyclic, square wave cathodic adsorptive stripping (SW-CAdS) and differential pulse cathodic adsorptive stripping (DP-CAdS) voltammetry under different experimental conditions. The voltammetric peak current and potential for the reduction of cilnidipine were analysed at different pH, scan rate and concentration. The voltammograms exhibited irreversible reduction of cilnidipine in B R buffer of pH 5.5. Cilnidipine gave one well-defined reduction peak at -0.821 potential versus Ag/AgCl reference electrode in BR buffer of pH 5.5. Reduction process was irreversible and diffusion controlled. Diffusion coefficients (7.45x10 -4 cm 2 /s and 6.45x10 -4 cm 2 /s), surface coverage (4.23x10 -3 mol/cm 2 and 98.01x10 -3 mol/cm 2 ) and heterogeneous rate constant (1.25x10 2 s -1 ) were calculated at bare GCE respectively. Based on CV, CPC and pH studies a reduction mechanism was proposed involving 6H + /6e -. The proposed square wave voltammetric method shows linearity over the concentration range (4.21x10 -6 -9.71x10 -3 M) The achieved limits of detection (LOD) and quantification (LOQ) are 5.44x10 -8 g/mL and 1.52x10 -7 g/mL respectively.