Electrochemical Behavior of Finasteride on Glassy Carbon Electrode Using Differential Pulse Voltammetric Technique

The direct and indirect electrochemical behavior of finasteride was studied using a differential pulse technique coupled with a three-electrode detection system consisting of 2 mm diameter glassy carbon as a working electrode, 2 mm diameter platinum wire as an auxiliary electrode, and silver/silver chloride saturated potassium chloride as reference electrode (Ag/AgCl sat KCl). The finasteride gives a weak reduction peak at -0.68 V. The calibration curve of finasteride was constructed using Briton- Robinson buffer solution (pH = 3), the plot of reduction peak current and concentration gives a linear relationship within the concentration range of 0.999x10-5-19.607x10-5 M, with a correlation coefficient of 0.9903. To increase the sensitivity of the method, an indirect determination of finasteride through its interaction with cupric ion was investigated in acetate buffer solution (pH=2) and followed the decrease in reduction peak current of cupric ion as a result of adding sequence addition of finasteride solution. The calibration curve for finasteride was also constructed for its interaction with cupric ions by measuring the decrease of cupric reduction peak current with the sequence additions of finasteride. The calibration curve was linear within the concentration range of in tablets.