ELECTROCHEMICAL CHARACTERISTICS OF TENOFOVIR AND ITS DETERMINATION IN DOSAGE FORM BY ELECTRO ANALYTICAL METHODS

摘要

The fully validated, simple, reliable and rapid voltammetric techniques were developed for the determination of Tenofovir disoproxil fumarate from its dosage form, based on its electrochemical oxidation at a glassy carbon electrode. Tenofovir disoproxil fumarate has been studied by cyclic, differential pulse, square wave and adsorptive stripping voltammetric techniques. Different parameters were optimized for the sensitive assay. At the glassy carbon electrode, the effects of pH on the peak potentials and the peak current, buffer types, concentrations, scan rates were studied as details. Depending on pH, the electrooxidation was found irreversible and exhibited mixed diffusion under adsorption controlled process. Voltammetric assay is described for the determination of Tenofovir disoproxil fumarate by adsorptive stripping differential pulse voltammetry and adsorptive stripping square-wave voltammetry. Using adsorptive stripping differential pulse and adsorptive stripping square wave voltammetric methods, in pH 4.7 acetate buffer solution, a linear response was obtained within the range of 6.0×10~(-7) - 6.0×10~(-5) M. The detection limits are estimated to be 1.02×10~(-7) M and 8.40×10~(-8) M with adsorptive stripping differential pulse and adsorptive stripping square wave voltammetry, respectively. These methods were successfully applied for the analysis of Tenofovir disoproxil fumarate from pharmaceutical dosage form. The repeatability, reproducibility, precision and accuracy of the methods in all working media were investigated. The standard addition method was used to obtain the accuracy results using recovery studies.