Sustainability-based assessment using HPLC method for estimation of colchicine and dexamethasone for multi-disease treatment: application to laboratory-made combination and rat plasma.

objectiveColchicine (COL) and dexamethasone (DEX) are well-established anti-inflammatory agents with proven efficacy across a spectrum of conditions, including gout, familial Mediterranean fever, cardiovascular diseases, and COVID-19. Their combined therapeutic use offers a synergistic effect that enhances inflammation control and immune modulation. Consequently, this study aimed to develop and validate a simple, sensitive, and sustainability-oriented HPLC-DAD method for the simultaneous determination of COL and DEX in laboratory-made tablets and rat plasma, and to perform a multi-tool assessment of the method's environmental and innovative performance. METHODOLOGY: Chromatographic separation was achieved on a reversed-phase long C8 column using acetonitrile:0.025 M phosphate buffer (pH 3) (40:60, v/v) at 1.0 mL/min using DAD tuned at 240 nm. Working ranges were 0.25-20 µg/mL (laboratory mixtures) and 1-20 µg/mL (plasma calibration with IS). Sample preparation for plasma employed protein precipitation with acetonitrile, centrifugation, evaporation, and reconstitution (300 µL). Method validation followed ICH and FDA bioanalytical guidance. KEY

findingsThe proposed method enabled the rapid and efficient separation of COL and DEX, yielding well-resolved peaks within 5 min and an excellent chromatographic performance. The method exhibited outstanding linearity (r > 0.999), high sensitivity, and reliable precision (intra- and inter-day RSD ≤ 6.25%), with extraction recoveries exceeding 85% in plasma. The sustainability assessment confirmed the environmentally friendly nature of the method, achieving high scores using multiple assessment metrics (Analytical Eco-Scale = 86; AGREE = 0.76; BAGI = 72.5; RGB model whiteness = 91.7). In addition, the violet innovation grade index (VIGI = 55) indicated a notable level of innovation, and the Environmental, Performance, and Practicality Index (EPPI = 87) indicated a high level of environmental sustainability, analytical efficiency, and real-world applicability. IMPACT: This is the first reported chromatographic method enabling simultaneous quantification of COL and DEX in pharmaceutical and plasma matrices together with a comprehensive, multi-tool sustainability assessment (including VIGI and EPPI). The method's short run time, high sensitivity, and favorable sustainability scores support its application in routine quality control and preclinical pharmacokinetic studies.