Febuxostat–p-Toluenesulfonic Acid Multi-Component Crystal: Characterization, Crystal Growth and Elucidation of the Salt/Co-Crystal Nature

The multi-component solid form of febuxostat (FEB) with p-toluenesulfonic acid was synthesized by solvent-drop grinding and cooling-evaporative crystallization characterized powder X-ray diffraction (XRPD), thermogravimetry (TGA), differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR). stable after exposure at elevated temperature relative humidity dissolution measurements revealed five-fold aqueous solubility improvement to FEB. Additionally, the decrease in pH suggests a potential for enhancing drug absorption lower stomach. In context regulatory requirements, salt/co-crystal nature elucidated combination process development crystal growth, followed SC-XRD FT-IR. Despite very weak basicity drug, structure determination combined analysis salt formation transfer acidic proton from Our study emphasizes importance knowledge understanding type interactions present crystals as well complying specific requirements.