Novel Application of UHPLC–MS, HRMS, and 2D‐NMR for Structural Elucidation of Eletriptan Hydrobromide and Its Novel Degradation Products

A stability-indicating UHPLC-MS method was developed to investigate the stress degradation behavior of eletriptan hydrobromide under ICH-recommended acidic, alkaline, neutral, oxidative, thermal, and photolytic conditions. Significant degradation was observed only under acidic and oxidative stress. Four degradation products were isolated and structurally characterized using HRMS and NMR, including one novel dimeric species. The optimized UHPLC-MS method provided an 8-min runtime with good resolution, sensitivity, and suitability for routine analysis. These results offer the first complete structural insight into the degradation pathways of eletriptan hydrobromide. The study supports improved quality control and long-term stability assessment. The findings also bridge the knowledge gap left by earlier studies that reported unassigned degradation products. Three new degradation products were identified and isolated from oxidative degradation and a new degradation product isolated from the acid degradation, providing the first documented structural characterization of all four degradation products. Furthermore, we develop a UPLC MS method having 8-min runtime and good peak shape and resolution by using Acquity BEH C18 column (100 × 2.1 mm, 1.7 μm) column.