Voltammetric Determination of Oxybutynin Hydrochloride Utilizing Pencil Graphite Electrode Decorated with Gold Nanoparticles

A novel voltammetric method was successfully applied for the determination of an anticholinergic drug, oxybutynin hydrochloride (OXB). The method is concerned with electrooxidation of the drug on the surface of pencil graphite electrode (PGE). In order to enhance the electrode sensitivity and peak current, the electrode was coated with gold nanoparticles (Au‐NPs) via electrochemical deposition using cyclic voltammetry from gold salt solution. The surface of Au‐NPs modified PGE has been characterized using scanning electron microscopy and X‐ray photoelectron spectroscopy. Various experimental variables were studied and optimized to enhance the sensor's response towards OXB. Quantitative determination of the drug was achieved in phosphate buffer pH 7.5 using differential pulse voltammetry by scanning the potential over range of 0.00 to 2.20 V with scan rate of 40 mV s−1. Validation of the method was achieved according to ICH guidelines. The method was found to be linear over concentration range (2.0×10−7–1.0×10−6 M). The suggested sensor was efficiently developed for the quantitative determination of OXB in pure form, pharmaceutical dosage form and spiked plasma samples.