Determination of Zidovudine in Pharmaceuticals by Differential Pulse Voltammetry

Abstract

The zidovudine (AZT) has been extensively used in the treatment of HIV patients due to its antiretroviral activity. The quality control of this substance in drugs is of outstanding importance to public health because of its undesirable effects and short therapeutic interval. For the determination of AZT in pharmaceuticals, an alternative analytical methodology using voltammetry was developed. The reduction of AZT at a hanging mercury drop electrode (HMDE) is at −0.96 V at pH 8.0. The influence of electroanalytical parameters, such as scan rate (20 mV/s), amplitude (50 mV), nature of the support electrolyte (phosphate buffer), and pH (8.0) on the voltammetric signal, was optimized. Under these optimized conditions, the AZT peak current varied linearly with its concentration from 0.25 to 1.25 mg/L (1 to 5 μM). Detection and determination limits of 0.0025 and 0.025 mg/L, respectively, and recovery of 99.88% with a relative standard deviation of 0.95% were obtained. The results obtained using this methodology in analyzing drugs containing AZT were compared favorably with those obtained by technique liquid chromatography as recommended by The United States Pharmacopoeia.