PROBLEM TO BE SOLVED: To provide: a therapeutically effective amount of at least one peptide or polypeptide, or analog or derivative thereof; and a composition with enhanced stability of the peptide or polypeptide or analog or derivative thereof.SOLUTION: A composition contains a stabilizing agent which is a medium chain fatty acid salt, medium chain fatty acid ester, medium chain fatty acid ether or medium chain fatty acid derivative having a carbon chain length of about 4 to about 20 carbon atoms or is a surface active agent. Also provided is a method for preparation of a peptide, polypeptide or protein, or an analog or derivative thereof.COPYRIGHT: (C)2015,JPO&INPIT【課題】治療上有効な量の少なくとも1種類のペプチド、ポリペプチド、またはその類似体もしくは誘導体、および該ペプチド、ポリペプチド、またはその類似体もしくは誘導体の安定性を向上させた組成物の提供。【解決手段】安定化剤として、約4~約20炭素原子の炭素鎖長を有する中鎖脂肪酸塩、中鎖脂肪酸のエステル、中鎖脂肪酸のエーテル、または中鎖脂肪酸の誘導体であるか、または界面活性剤を含む組成物。ペプチド、ポリペプチド、タンパク質、それらの類似体及び/又はそれらの誘導体の調製のための方法。【選択図】なし