DOI: https://doi.org/10.55373/mjchem.v28i1.341

Keywords: Risperidone (RSP), Alizarin Red S (ARS), UV-Vis, Green analytical chemistry, White analytical chemistry

Abstract

Risperidone is an important atypical antipsychotic used to treat schizophrenia, bipolar disorder, and autism-related irritability. It works by blocking the receptors for dopamine and serotonin. Accurate and eco-friendly methods for its determination in pharmaceuticals are essential for quality control. Two rapid and straightforward analytical approaches-spectrophotometric and flow injection analysis (FIA) were developed for the quantitative determination of Risperidone (RSP) in its pure form and in pharmaceutical formulations. Both methods rely on the formation of a purple ion-pair complex between RSP and Alizarin Red S (ARS), exhibiting a maximum absorbance at 534 nm. The calibration curves for Method A (spectrophotometric) and Method B (FIA) were linear within the concentration ranges of 10-125 μg.mL^-1 and 0.078-11.826 μg.mL^-1, respectively, adhering to Beer’s law. The calculated limits of detection (LOD) and limits of quantification (LOQ) were 4.07 μg.mL^-1 and 12.33 μg.mL^-1 for Method A, and 0.037 μg.mL^-1 and 0.112 μg.mL^-1 for Method B. The methods demonstrated high precision with relative standard deviation (RSD) values below 1.25%. The environmental sustainability of the developed methods was assessed using several greenness evaluation tools, including the Analytical Eco-Scale (AES), ChlorTox, and Analytical GREEnness (AGREE) metrics, all of which indicated a strong green profile. Furthermore, White Analytical Chemistry (WAC) principles were evaluated using the RGB12 model, yielding whiteness scores exceeding 85, which confirms the method’s balanced analytical performance. The validated procedures were effectively applied to the analysis of RSP in commercial pharmaceutical preparations.