Patent ID: 8574601

Claim:
A pharmaceutical composition comprising: a polymer micelle composition; and a drug encapsulated in the polymer micelle composition, the drug having a molecular weight of 1,500 or more and being selected from the group consisting of water-soluble physiologically active polypeptides and water-soluble physiologically active proteins, wherein: the polymer micelle composition comprises a plurality of first block copolymers and a plurality of second block copolymers, each having a hydrophobic polymer chain segment and a hydrophilic polymer chain segment, the first and second block copolymers being arranged in a state in which the respective hydrophobic polymer chain segments are directed radially inward and the respective hydrophilic polymer chain segments are directed radially outward; the first block copolymers have a greater affinity for HDL than the second block copolymers; the hydrophobic polymer chain segment of the first block copolymers comprises a polyamino acid including repeating units of a hydrophobic derivative of an amino acid, wherein the amino acid derivative comprises a side chain to which a sterol residue is covalently attached; the hydrophobic polymer chain segment of the second block copolymers comprises a polyamino acid including repeating units of a hydrophobic derivative of an amino acid, wherein the amino acid derivative comprises a side chain to which a hydrophobic group having a linear or branched structure is bound; and detachment of the first block copolymers from the polymer micelle composition is inducible by adhesion of the first block copolymers to HDL, such that at least one gap formed by the detachment of the first block copolymers permits release of the encapsulated drug, which is not bound to the first or second block copolymers, through the at least one gap and the second block copolymers promote resealing of the at least one gap.