Firefly Algorithm–PLS for Synchronous Fluorescence Analysis of Olmesartan and Rosuvastatin in Pharmaceutical and Plasma Samples

This study presents a validated analytical method for the simultaneous determination of olmesartan and rosuvastatin using synchronous spectrofluorimetry integrated with advanced chemometric modeling. The method addresses the limitations of conventional approaches by combining the firefly algorithm (FA) with partial least squares (PLS) regression to overcome spectral overlap challenges. Experimental conditions were optimized, with ethanol as solvent and 0.05% w/v SDS as fluorescence enhancer, achieving a 1.6- and 1.4-fold increase in sensitivity for olmesartan and rosuvastatin, respectively. The FA-PLS approach demonstrated superior performance over conventional PLS, requiring fewer latent variables (2 vs. 4) while achieving lower detection limits in the ng/mL range, markedly tighter residual distributions (±2%), and improved prediction accuracy (RRMSEP: 1.34 and 1.40). The method was successfully validated according to ICH guidelines and applied to pharmaceutical formulations and plasma samples, yielding recoveries of 99.87 ± 1.02% and 99.68 ± 0.56% for olmesartan and rosuvastatin, respectively. Statistical comparison with the reported HPLC method confirmed method equivalence through t-tests, F-tests, and interval hypothesis testing. Environmental impact assessment using AGREE (0.75) and BAGI (75.0) indices demonstrated superior greenness compared to the conventional HPLC method while maintaining excellent analytical practicality, establishing this method as a sustainable alternative for routine pharmaceutical analysis and biomedical applications.