Novel crystal of quinoxalinedione derivative anhydride
The object of the present invention is to provide a novel crystal of a quinoxalinedione derivative as an AMPA antagonist, which enables providing a bulk for manufacturing pharmaceuticals that are stable under any humidity conditions.
1 . An α crystal of free form anhydride of [7-(1H-imidazol-1-yl)-6-nitro-2,3-dioxo-3,4-dihydroquinoxalin-1(2H)-yl]acetic acid.
2 . The α crystal according to claim 1 , wherein the crystal exhibits peaks at diffraction angles of 9.1°, 19.4°, 22.5°, 23.3°, 23.9°, 25.7° and 26.2° in X-ray powder diffraction patterns.
3 . The α crystal according to claim 2 , wherein the crystal exhibits diffraction peaks at the same diffraction angles as those of the X-ray powder diffraction pattern shown in FIG. 1 .
4 . The α crystal according to claim 3 , wherein the crystal exhibits an exothermic peak accompanying decomposition in the vicinity of 341° C. according to thermal analysis (TG-DSC).
5 . An AMPA receptor antagonist comprising the a crystal of free form anhydride of the compound A according to any one of claims 1 to 3 , as an active ingredient.
6 . A pharmaceutical comprising the crystal according to claim 3 , as a therapeutic agent for treating cerebral infarction.
7 . Use of the α crystal for manufacturing a pharmaceutical for treating cerebral infarction, comprising a therapeutically effective amount of the α crystal according to any one of claims 1 to 3 .
8 . A method of treating cerebral infarction, comprising administering to a patient a therapeutically effective amount of the α crystal according to any one of claims 1 to 3 .