Fluorescein‐Based Charge–Transfer Fluorimetric Method for Quantification of Gliptin Drugs: Comprehensive Greenness, Blueness, and Sustainability Assessment

A green, sustainable, and highly sensitive fluorimetric method was developed for the quantitative determination of the antidiabetic agents alogliptin, saxagliptin, and vildagliptin in bulk powders and commercial formulations. The assay relies on charge-transfer complexation with fluorescein in acetate buffer at drug-specific pH values, producing enhanced fluorescence at 513 nm (λ_ex = 470 nm). Under optimized conditions, linear responses were obtained within 2.00-50.00 μg/mL for saxagliptin, 1.00-30.00 μg/mL for vildagliptin, and 1.00-31.25 μg/mL for alogliptin, with detection limits of 0.54, 0.27, and 0.23 μg/mL, respectively. The corresponding quantification limits were 1.63, 0.81, and 0.70 μg/mL. The method exhibited excellent correlation coefficients across all ranges and was validated in accordance with ICH guidelines. Application to pharmaceutical tablets yielded results consistent with reported reference methods, confirming accuracy and precision without significant statistical differences. Greenness and sustainability were evaluated using multiple assessment tools (AGSA, GAPI, AGREE, MoGAPI, Eco-scale, CACI, BAGI, CaFRI, and MA tool), confirming the eco-friendly profile of the assay. The proposed method provides a reliable, green alternative for routine quality control of gliptins in pharmaceutical preparations.