| abstract |
The invention provides crystals of dihydrochloride monohydrate of the compound of the following formula having an Aβ production inhibiting effect which crystals are characterized by exhibiting a diffraction peak at an angle of diffraction (2θ ± 0.2°) of 10.9° in powder X-ray diffractometry. Further, the invention also provides the compound in the form of various salts, crystal forms and amorphous forms which are suitable for the development of drugs. |