Fluorescence Quenching–Based Quantification of Famotidine in Pharmaceutical Formulations and Biological Fluids Using Eosin Y

A simple, selective, and economic spectrofluorimetric procedure was developed for famotidine determination with Eosin Y. For famotidine determination, the fluorescence intensity of Eosin Y was quenched with famotidine. The decrease was due to forming an ion-pair complex between famotidine and Eosin Y. Maximum fluorescence was noted at 546 nm at a 301 nm excitation wavelength. The investigation focused on different parameters affecting the formation of complexes. A correlation coefficient of 0.9969 was obtained for the fluorescence quenching values of famotidine in the linear range of 1-20 μg mL-1 with the optimal parameters. The limits of detection (LOD) were 4.67 ng mL-1, and the limits of quantification (LOQ) were 0.015 μg mL-1. It is possible to quantify famotidine without interference from standard excipients. The proposed method has proven effective for evaluating famotidine in its standard form, within commercial products, and in biological samples. Percentage recoveries ranged from 99.30% to 103.50% for pharmaceutical formulation and 98.78% to 101.56% for biological fluids. The environmental sustainability of the proposed method was evaluated using AGREE and the analytical Eco-Scale. The ICH guideline was used to test the validity of the method provided, and it can therefore be employed to evaluate famotidine in commercial dosage forms, yielding acceptable results.