Patent ID: 8741339

Claim:
A polymer micelle encapsulating a drug comprising: a polymer α represented by the general formula I: Z-A 1 -B 1 (I); and a polymer β represented by the general formula II: A 2 -B 2 (-D) (II) where: Z represents a residue of a compound having a target binding site; A 1 and A 2 each independently represent a hydrophilic segment of a polyethylene glycol chain; B 1 and B 2 each independently represent a hydrophobic segment of a polyamino acid chain; and D represents the drug with the proviso that one or more copies of the drug is (are) respectively covalently bound to one or more side chains of the polyamino acid chain of the polymer β, wherein when the polymer micelles collapse in blood, the polymer β is excreted through metabolism, to thereby prevent a normal cell from being damaged by the drug.