Design and optimization of a new voltammetric method for determination of isoniazid by using PEDOT modified gold electrode in pharmaceuticals

Isoniazid (inh) was studied with regard to its electrochemical treatment on a strongly alkaline solution of a poly (3,4-ethylenedioxythiophene)-modified gold electrode,using both cyclic voltammetric and controlled potential techniques. electrocatalytic performance measurements of this composite electrode toward oxidation of inh exhibited an increase of 4-folds in oxidation peak densities compared to the bare gold electrode. central composite design method was used to obtain optimum experimental conditions,and used critical parameters (ph (a),scan rate (mv/s,b) and temperature (°c,c) to assess the effects on amperometric response. optimum experimental conditions were achieved by using a ph of 9.2 with a scan rate of 260 mv/s and a temperature of 30 °c. under these circumstances,a good linear relationship was observed between peak current densities and inh concentration in the range of 0.05-2 μm,with correlation coefficient of 0.9998. furthermore,the method was very sensitive (limit of quantitation,0.0043 μm),accurate (relative error,-5.65 to 4.03) and precise (relative standard deviation %,≤ 7.97). the method was also applied to determine inh in pharmaceutical formulations,and statistically compared the results with the official method using the two one-sided equivalence test; the results were in good agreement with those obtained by the official and reported methods. © 2016 by school of pharmacy shaheed beheshti university of medical sciences and health services.