The problem of the present invention is provision of a solid preparation containing N-methyl-N-(1-methylethyl)-6,7,8,9-tetrahydropyrazino[2,3-f][1,4]oxazepin-3-amine or a salt thereof, which may release the compound in a sustained manner. A solid preparation containing N-methyl-N-(1-methylethyl)-6,7,8,9-tetrahydropyrazino[2,3-f][1,4]oxazep in-3-amine or a salt thereof, and a hydrophilic gel-forming polymer.本發明之問題為提供含有N-甲基-N-(1-甲基乙基)-6,7,8,9-四氫吡嗪并[2,3-f][1,4]氧雜氮雜環庚三烯-3-胺或其鹽的固形製劑，該固形製劑可以持續的方式釋放化合物。一種含有N-甲基-N-(1-甲基乙基)-6,7,8,9-四氫吡嗪并[2,3-f][1,4]氧雜氮雜環庚三烯-3-胺或其鹽及形成親水性凝膠之聚合物的固形製劑。
