<；P>；PROBLEM TO BE SOLVED: To provide a polyurethane derivative containing a sugar residue-modified oligo sugar, which is thermoplastic and soluble in solvents and excellent in moldability to a film and a coating film, to provide its simple and low cost production method and to provide physiologically active substances. <；P>；SOLUTION: A dicarboxylic anhydride is reacted with a polyurethane derivative containing a carboxylic group-modified oligo sugar, and further an amino sugar is reacted with the above product, whereby a polyurethane derivative wherein a sugar chain is introduced into a side chain on an oligo sugar is produced. The polyurethane derivative is used as a physiologically active substance. <；P>；COPYRIGHT: (C)2008,JPO&INPIT
