Stability-indicating RP-HPLC-DAD method for aspirin and vonoprazan using analytical quality by design and comprehensive greenness assessment.

This fixed-dose combination is intended for patients requiring long-term aspirin-based antiplatelet therapy who are at increased risk of gastrointestinal complications, with vonoprazan providing gastroprotection through potent acid suppression. A robust RP-HPLC method was developed through Failure Mode Effects Analysis (FMEA) risk assessment and face-centered central composite design (FCCD) optimization. Chromatographic separation on a Zorbax SB-C18 column (250 × 4.6 mm, 5 μm) using isocratic elution with water-acetonitrile-formic acid (75:25:0.05, v/v/v) at 0.8 mL/min and 30 °C achieved baseline resolution within 8.5 min, with quantification of both analytes performed at a single wavelength of 280 nm. Quantification was performed at a single detection wavelength of 280 nm, while peak purity was evaluated using DAD spectral data over 220-350 nm. Peak purity was confirmed by DAD spectral analysis, with purity angle values lower than purity threshold values for both Aspirin (ASP) and vonoprazan fumarate (VPZ) under all tested conditions. The method demonstrated stability-indicating specificity through ICH Q1A(R2)-compliant forced degradation studies, while LC-MS/MS characterization showed that VPZ underwent hydroxylation (m/z 378.1754), N-oxidation (m/z 346.0993), demethylation (m/z 315.0568), and pyridine cleavage (m/z 301.1419), among the identified degradation products. Environmental sustainability was comprehensively evaluated using complementary assessment tools, namely the GAPI pictogram, AGREE (0.79), Eco-Scale (90/100), ChlorTox (0.43 mg CHCl₃-eq), BAGI (82.5), and CACI (85.0), confirming favorable environmental compatibility and practical feasibility for routine quality-control application.