This application describes the polymorph bs of the crystallization of the N- of formula (I) (2- aminophenyls) -4- [N- (pyridin-3-yl) methyloxycarbonylaminos methyl] benzamide (MS-275), and prepare the purposes of the method for the compound and the drug of its disease selected as treatment.本申請描述了式(I)的N-(2-氨基苯基)-4-[N-(吡啶-3-基)甲氧基羰基氨基甲基]苯甲酰胺(MS-275)的結晶的多晶型物B,以及製備所述化合物的方法和其作爲治療所選的疾病的藥物的用途。