| abstract |
Disclosed is a novel crystal of 5-methyl-2-(piperazin-1-yl)benzenesulfonic acid anhydride or monohydrate. Specifically disclosed is a type-I or -II crystal of 5-methyl-2-(piperazin-1-yl)benzenesulfonic acid anhydride, which has a specific diffraction peak in a powder X-ray diffraction spectrum. Also specifically disclosed is a type-II or -III crystal of 5-methyl-2-(piperazin-1-yl)benzenesulfonic acid monohydrate, which has a specific diffraction peak in a powder X-ray diffraction spectrum. |