This invention relates to a solid dispersion comprising: a compound represented by the general formula (I) below or a pharmaceutically acceptable salt thereof and a hypromellose derivative:wherein R1is an unsubstituted phenyl group, or a phenyl group substituted by a substituent, the substituent being a C1-8alkyl group, a C1-8alkyl group substituted by a halogen atom, a C1-8alkoxy group, a C2-8alkoxycarbonyl group, a formyl group, a carboxyl group, a halogen atom, a phenyl group or a phenoxy group； R2is a cyano group or a nitro group； R3is a hydroxyl group； X is an oxygen atom or -S(O)n-； n is an integer of from 0 to 2； and Y is an oxygen atom or a sulfur atom.本發明有關一種固體分散體，包含通式(I)所示化合物或其醫藥上可接受之鹽及羥丙甲纖維素衍生物；(式中，R1表示無取代之苯基或經取代基取代之苯基，前述取代基表示碳數1~8之烷基、經鹵素原子取代且碳數1~8之烷基、碳數1~8之烷氧基、碳數2~8之烷氧羰基、甲醯基、羧基、鹵素原子、苯基或苯氧基；R2表示氰基或硝基；R3表示羥基；X表示氧原子或-S(O)n-，n表示0~2之整數；Y表示氧原子或硫原子)。
