Eco-Friendly Simultaneous Quantification of Domperidone and Safinamide by Spectral Resolution using deconvoluted Synchronous Fluorescence: Application to Spiked Human Plasma

A novel, eco-friendly deconvoluted synchronous spectrofluorimetric method has been developed and validated for the simultaneous determination of domperidone (DOM) and safinamide (SAF), a potential combination used to address Parkinson's disease–associated gastrointestinal dysfunction. Their combined administration necessitates a reliable analytical method for therapeutic monitoring and formulation quality control. Traditional spectrofluorimetric techniques fail to resolve the significant spectral overlap between these two compounds. In this study, a deconvoluted synchronous spectrofluorimetric method, using Fourier self-deconvolution at Δλ = 30 nm, successfully resolved the overlapping fluorescence spectra without any need for physical separation. It showed excellent linearity (DOM: 10–1500 ng/mL, SAF: 50–2000 ng/mL), with low LOD (2.75 ng/mL for DOM and 11.77 ng/mL for SAF), high recovery rates in both pharmaceutical forms and spiked human plasma (above 90%), and outstanding selectivity and robustness. Sustainability of the current method was assessed using spider chart measure, green solvent selection tool, Analytical GREEnness Metric, Modified Green Analytical Procedure index, and Blue Applicability Grade Index. The proposed technique represents a simple, sensitive, and sustainable tool for routine analysis of this therapeutically significant drug pair.