Environmental sensitivity of prasugrel hydrobromide: a study of light and relative humidity effects

Abstract The thienopyridine derivative—prasugrel hydrobromide—is commonly used as an antiplatelet drug to prevent thrombotic events. Its physicochemical properties indicate susceptibility to environmental factors such as light and humidity, which can affect its solid-state stability and, consequently, its pharmaceutical behaviour. Knowledge of the solid-state stability profile of this compound is essential to enable control of processing and storage conditions. The objective was to assess the effects of light and moisture on prasugrel hydrobromide and its binary mixtures with different pharmaceutical excipients. Samples were stored at room temperature (approximately 60–70% relative humidity) for seven days in open glass containers. Assessment was performed by FTIR-ATR spectroscopy and thermal analysis (TG/HF). Measurements showed that exposure to humidity induced detectable and reversible structural and thermal changes, most of which were associated with moisture adsorption and hydrogen-bond rearrangements. This study demonstrates the importance of environmental control during storage, and further studies to understand behaviour as a function of moisture are essential for ensuring the long-term stability of prasugrel hydrobromide in solid pharmaceutical formulations.