The present invention provides a tetomilast crystal that is industrially easily produced in a large volurme.(1) a tetomilast hydrate crystal having a powder X-ray diffraction spectrum that is substantially the same as the powder X-ray diffractiion spectrum shown in Fig. 2； (2) an anhydrous tetomilast type A crystal having a powder X-ray diffraction spectrum that is substantially the same as the powder X-ray diffraction spectrum shown in Fig. 4； (3) an anhydrous tetomilast type C crystal having a powder X-ray diffraction spectrum that is substantially the same as the powder X-ray diiffraction spectrum shown in Fig. 8； (4) a tetomilast acetonitrile solvate crystal having a powder X-ray diffraction spectrum that is substantially the same as the powder X-ray diffraction spectrum shown in Fig. 10； and (5) a mixture consisting of the above anhydrous tetomilast type A crystal and an anhydrous tetomilast type B crystal. These crystals are stable towards heat and moisture, and are also excellent in terms of the disintegration property and dissolution property of tablets. Accordingly, these crystals are preferably used as pharmaceutical compositions.本發明提供工業上容易以大體積生產之替妥牟拉晶體。(1)一種替妥牟拉(tetomilast)水合物晶體，其係具有實質上與圖2中所顯示的粉末X射線繞射光譜相同之粉末X射線繞射光譜；(2)一種無水替妥牟拉A型晶體，其係具有實質上與圖4中所顯示的粉末X射線繞射光譜相同之粉末X射線繞射光譜；(3)一種無水替妥牟拉C型晶體，其係具有實質上與圖8中所顯示的粉末X射線繞射光譜相同之粉末X射線繞射光譜；(4)一種替妥牟拉乙腈溶劑合物晶體，其係具有實質上與圖10中所顯示的粉末X射線繞射光譜相同之粉末X射線繞射光譜；和(5)一種混合物，其係由上述無水替妥牟拉A型晶體和無水替妥牟拉B型晶體組成。這些晶體對熱和水分穩定，且自錠劑之崩解性質和溶解性質之觀點也是優異的。因此，這些晶體較佳地用作醫藥組成物。
