PHARMACEUTICAL COMPOSITION

摘要

Provided is a carrier that can achieve both the stability of a biological drug in blood and its release in a target cell. A pharmaceutical composition of the present invention includes: a polymer unit ± having a hydrophilic polymer chain segment and a cationic polymer chain segment; a polymer unit ² having a hydrophilic polymer chain segment and a cationic polymer chain segment; and a drug. The polymer unit ± and the polymer unit ² form a micelle by being radially arranged so that the cationic polymer chain segments are directed inward and the hydrophilic polymer chain segments are directed outward, the micelle encapsulating the drug. The cationic polymer chain segment of the polymer unit ± has a phenylboronic acid group in a side chain, and the cationic polymer chain segment of the polymer unit ² has a phenylboronic acid binding site in a side chain, and the phenylboronic acid group and the phenylboronic acid binding site form a cross-linked structure that is disintegrable under an acidic environment or in the presence of a substance capable of competitive binding.