PROBLEM TO BE SOLVED: To provide a dry powder that is suitable for use in forming a hydrogel and is stable at ambient conditions, and to provide a method for preparing a hydrogel using the dry powder.SOLUTION: There is provided a method for preparing a hydrogel including the step of forming a dry powder which comprises a prepolymer containing a straight chain polyethylene glycol preferably terminally derivatized with acrylate, methacrylate, vinyl, or substituted vinyl terminal group and a thermally activated free radical initiator selected from the group consisting of sodium persulfate, potassium persulfate, and ammonium persulfate and has a particle size of about 500 microns or less as well as a reaction mixture comprising the dry powder and a buffered aqueous solution. The hydrogel is useful for treating diseases such as Aortic Aneurysms.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2020,JPO&INPIT【課題】ヒドロゲルの形成用途に適した、外気条件で安定な乾燥粉末、及び該乾燥粉末を用いたヒドロゲルの調製方法の提供。【解決手段】末端がアクリラート、メタクリラート、ビニル、又は置換ビニル末端基で誘導体化されていることが好ましい直鎖ポリエチレングリコールを含むプレポリマー、及び過硫酸ナトリウム、過硫酸カリウム、過硫酸アンモニウムより選択される熱活性化フリーラジカル開始剤を含み、約５００ミクロン以下の粒子径の乾燥粉末、並びに、該乾燥粉末及び緩衝水溶液を含む反応混合物を形成させる工程を含む、ヒドロゲルの調製方法。本ヒドロゲルは大動脈瘤の治療等に有用である。【選択図】図１
