| 摘要 |
PROBLEM TO BE SOLVED: To obtain a polymer which is branched-chain ester comprising polyol units having groups having electrolytic characteristics and polycarboxylic acid residues, has a specified wt. average mol.wt., contains biocompatible Mg ions as a catalyst residue, and is convertible into microparticles having a capacity for bearing a high load of an acting substance. SOLUTION: A polyol which has groups having electrolytic characteristics and selected from among dextran sulfate, xylan sulfate, and cyclodextrin sulfate groups is used. A hydroxycarboxylic ester (e.g. a lactic or glycolic ester), a lactide and a glycolide, and sodium dextlan sulfate are mixed and thermally melted in a nitrogen atmosphere. Then a catalyst (e.g. a 2-6C dialkylmagnesium) is added to the resultant melt under stirring to cause a reaction, thus giving a branched-chain polymer contg. biocompatible Mg ions and having a wt. average mol.wt. of 500,000 or lower. This polymer is spray dried to give microparticles. |
