Preformulation Study for Seven Solid Forms of Dotinurad

Dotinurad, a novel selective urate reabsorption inhibitor, was studied for preformulation beneficiation by supramolecular methods. Two polymorphic forms (form I, form II), a monohydrate, and four solvates were prepared and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, and thermal analysis, which enabled the respective molecular conformation, intermolecular interactions, and packing arrangements to be determined. Combined with Hirshfeld surface analysis and energy networks, the stability and conformations of the above seven solid forms were studied by thermal analysis, crystal structure, and experimental results of solvent-mediated transitions and heat-treated transitions. Interestingly, form I and five solvates were transformed to form II under solvent suspension easily and quickly. The desolvation of DT solvates resulted in form II, which is mainly related to the hydrogen bonds between DT molecules and solvents.