Physicochemical characterization of glybuzole polymorphs and their pharmaceutical properties.

Systematic polymorphic screening tests were performed using 11 kinds of solvents and 6 kinds of preparation methods, and the three specific modifications of glybuzole (forms I and II and amorphous form) were identified by X-ray diffractometry and differential thermal analysis (DTA). The physicochemical properties of forms I and II and amorphous forms were measured using X-ray diffractometry, differential scanning calorimetry (DSC), thermogravimetry (TG), scanning electron microscopy (SEM), solubility tests, and others. The solubilities of all modifications in JP XII, first and second fluid (pH 1.2 and 6.8, respectively) were evaluated at 37 degrees C. Forms I and II and the amorphous form showed almost equivalent solubilities. Forms I and II were stable polymorphic forms at 0% and 75% relative humidity (RH), respectively, at 40 degrees C for 2 months, but the amorphous form was not stable. The crystallization rates of the amorphous form at 0% and 75% RH at 40 degrees C were estimated by X-ray diffraction analysis based on the Jander equation, and the rate at 0% RH was 364 times slower than that at 75% RH.