Silver Nanoclay Human Albumin Serum Composite Electrochemical Biosensor for Quantification of Zidovudine in Tablets

This work aims to develop an electrochemical biosensor for the analysis of zidovudine (ZDV) in commercial tablets.

The biosensor utilised silver nanoclay composites (AgNCs) together with drop-coated Human Serum Albumin (HSA) on a glassy carbon electrode (GCE/AgNCs/HSA). The electrochemical properties of the GCE/AgNCs/HSA were studied using cyclic voltammetry (CV) and analysed using the Randles-Sevcik equation. Procedurally, optimised differential pulse voltammetry (DPV) technique in 1 M PBS, pH 7.04, was used to determine analytical parameters of the methods, validation, and study of commercial tablets.

The optimum procedural conditions used were -0.4 V to -1 V potential range, 0.0405 V step potential, 0.075 V modulation amplitude, 0.01 s modulation time, and 0.25 s interval time. GCE/AgNCs/HSA film's electrochemical properties obtained were a diffusion coefficient (D) of 1.55 × 10-11 cm2.s-1, a heterogeneous rate constant (Ks) of 3.40 × 10-6 cm.s-1, with two electrons. The calibration graph linear range was from 0.12 to 6.98 μM with a low limit of detection (LOD) of 0.3 μM, and 1.0 μM limit of quantification (LOQ). Method validation showed an acceptable %RSD for reproducibility and repeatability. The sensor was stable over 10 days and remained unaffected by the presence of the interferences studied. The commercial study of 300 mg commercial tablets was found to be 301.3 mg with 1.9% RSD, which is in agreement with the tablet's stated amount.

The development of the GCE/AgNCs/HSA biosensor was successful and efficiently used to quantify ZDV in tablets.