| 摘要 |
PROBLEM TO BE SOLVED: To prepare a controlled release base and a controlled release film- forming agent both capable of releasing drug at a stable releasing speed for a releasing period by irradiating ultraviolet rays to of a specific polyester, its copolymer or their blended polymer. SOLUTION: This controlled release base and the controlled release film- forming agent are prepared by irradiating ultraviolet rays to a polyester having 300-50,000 (pref. 900-30,000) weight average molecular weight and mainly comprising (usually >=70 mol%, pref. >= 80 mol%, more pref. >=90 mol%) aliphatic structural units, its copolymer or their blended polymer. The polyester cited is (A) the one mainly comprising aliphatic hydroxycarboxylic acid units, (B) the one mainly comprising aliphatic hydroxycarboxylic acid units, aliphatic polybasic carboxylic acid units and aliphatic polyhydric alcohol units, or the like.
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