| abstract |
[PROBLEMS] To provide crystals of a benzoxadiazole derivative which are any of β-form crystals, Ϝ-form crystals, and α-form crystals. The derivative of certain quality in a single crystal form can be obtained with good reproducibility. The crystals can be stably supplied as crystals of the raw drug for use in the production of medicines, show low hygroscopicity, which is especially suitable for mass synthesis in industrial production, and are excellent especially in light stability. [MEANS FOR SOLVING PROBLEMS] The crystals are, for example, β-form crystals of 4-[3-isopropyl-5-(6-phenyl-3-pyridyl)-4H-1,2,4-triazol-4-yl]-2,1,3-benzoxadiazole which in differential scanning calorimetry (DSC analysis) have an endothermic peak at 145-150°C and in X-ray powder diffractometry have peaks at 2θ's (°) of 9.8, 11.1, 12.8, 13.3, 17.1, 20.2, 21.2, and 22.3. |