PROBLEM TO BE SOLVED: To provide amorphous rifaximin useful for the treatment of bowel-related diseases such as irritable bowel syndrome, diarrhea, Crohn's disease, chronic pancreatitis, pancreatic insufficiency, and colitis, a method of preparing the same and a pharmaceutical composition comprising the same.SOLUTION: The present invention provides rifaximin of amorphous form characterized by a specific XRPD pattern and a specific FT-IR spectrum.SELECTED DRAWING: None【課題】過敏性腸症候群、下痢、クローン病、慢性膵炎、膵不全、大腸炎等の腸関連疾患の処置に有用な、無定形リファキシミン、それを作製する方法及びそれを含む医薬組成物の提供。【解決手段】特定のＸＲＰＤパターン及び特定のＦＴ-ＩＲスペクトルにより特徴付けられる無定形形態のリファキシミン。【選択図】なし
