PROBLEM TO BE SOLVED: To provide a phosphorylated polymer derivative useful as a dispersant that can stably maintain micelle formation and is used as polymer micelle drug carrier, and to provide a dispersant using the phosphorylated polymer derivative.SOLUTION: A phosphorylated polymer derivative comprises a structural unit represented by formula (II) in a repeating structural unit represented by formula (I), in which the structural unit represented by formula (II) interposes partially between the repeating structural units represented by formula (I). A ratio of the number of the structural unit represented by formula (II) to the sum of the number of the structural unit represented by formula (I) and the number of the structural unit represented by formula (II) is 0.10 or more and 0.35 or less.COPYRIGHT: (C)2015,JPO&INPIT【課題】ミセル形成を安定的に維持することができ、高分子ミセル型薬物キャリアとして用いる分散剤として有用なリン酸化ポリマー誘導体を提供する。そのリン酸化ポリマー誘導体を用いた分散剤を提供する。【解決手段】式(I)で表される繰り返し構造単位に、式(I)で表される構造単位の繰り返し構造中に、部分的に介在する式(II)で表される構造単位を有し、式(I)で表される構造単位の数及び式(II)で表される構造単位の数の合計に対する、式(II)で表される構造単位の数の割合が0.10以上0.35以下であるリン酸化ポリマー誘導体。【選択図】なし
