Sustainable Spectrofluorometric Method for the Determination of Zuranolone in Pharmaceutical Formulations Using Propidium Iodide Ion‐Pair Complex

A novel spectrofluorometric method that leverages ion-pair complexation with propidium iodide to achieve indirect fluorescence enhancement for the sensitive measurement of zuranolone is introduced. In acidic media, protonated propidium iodide interacts selectively with negatively charged zuranolone, forming a stable ion-pair complex. This interaction induces conformational changes in propidium iodide, markedly increasing its fluorescence and enabling accurate detection of zuranolone. The method achieved quantification within the range of 10-300 ng/mL, with limits of detection and quantification of 2.50 and 7.50 ng/mL, respectively. Validation according to International Conference on Harmonization guidelines confirmed its linearity, precision, accuracy, and selectivity. Application to Zurzuvae capsules demonstrated excellent accuracy and reliable analytical performance. Furthermore, high Analytical GREEnness and favorable Green Analytical Procedure Index scores highlighted the method's environmental sustainability, positioning it as a robust, eco-friendly tool for routine analysis.