Gold Nanoparticles-Modified Screen-Printed Carbon Electrode for Voltammetric Determination of Sildenafil Citrate (Viagra) in Pure Form, Biological and Pharmaceutical Formulations

Abstract

In this work, a highly sensitive electrochemical sensor for the determination of sildenafil citrate (SILC) drug (the active component of Viagra) was fabricated by electrodeposition of gold nanoparticles (AuNPs) onto a screen-printed glassy carbon electrode (SPGCE). Cyclic voltammetry (CV) and Square wave voltammetry (SWV) were used to characterize the redox behavior of SILC in absence and presence of AuNPs. The response of the SPGCE electrode for SILC determination was observed to be enhanced in presence of AuNPs. The peak currents for SILC at AuNPs/SPGCE show a linear response in the concentration range from 1.8×10−6 to 3.3×10−5 mol L-1 with good reproducibility. The limit of detection was found to be 5.2×10-10 mol L-1.An interference study was also carried out in presence of high concentration of ascorbic acid (AA), and uric acid (UA) to estimate the high selectivity of the electrode. The modified sensor was successfully applied for the determination of SILC in simulated human urine samples and pharmaceutical formulation with good agreement between the added and recovery values.