Electrochemical determination of Azelastine using a Calix[4]arene-doped polyaniline screen-printed sensor in pharmaceutical and biological samples

Abstract

Careful choice of ion-sensing components and substrates is the primary focus when developing ion-selective electrodes to achieve maximum sensitivity, selectivity, stability and accuracy. This study aims to develop and optimize two miniaturized screen-printed solid-contact ion-selective electrodes to quantify Azelastine HCl (AZE) in various pharmaceutical preparations and complex spiked biological samples. The electrodes' optimization involved doping ion-sensing membranes with the most selective ionophore for the studied drug, followed by electro-polymerization of polyaniline (PANI) conducting polymer at screen-printed electrode. Two screen-printed electrodes were developed for AZE determination, and their electrochemical performance was evaluated following IUPAC recommendations. The optimal calix[4]arene-doped PANI-based screen-printed electrode reached a detection limit of 2.50 × 10−6 M for AZE with a dynamic response of about 3 s. It successfully quantified AZE in its pure form, pharmaceutical dosage forms, spiked aqueous humor and plasma, which demonstrates potential applicability. Its selectivity was assessed in the presence of the induced degradation products of AZE, interfering ions, and the co-formulated drug, fluticasone propionate. A comparison regarding greenness between the developed and two reported methods was established by means of Modified Green Analytical Procedure Index (Mo-GAPI) and Analytical Greenness (AGREE) assessment tools. Sustainability profile was established using NQS index, showing alignment of the study with the UN-17 SDGs.