Active-targeting-type polymer derivative, composition containing said polymer derivative, and uses of said polymer derivative and said composition

1. A composition comprising a block copolymer (A) and a block copolymer (C),

wherein the block copolymer (A) comprising a hydrophilic polymer segment linked to a hydrophobic polymer segment, the hydrophilic polymer segment containing a polyethylene glycol chain, and the hydrophobic polymer segment containing a polyamino acid chain having a hydrophobic substituent in a side chain;

wherein the block copolymer (A) is represented by General Formula (1):

wherein

R 1 represents a bonding residue of a target binding site;

ta represents an integer from 20 to 140;

Aa represents a substituted (C1-C6) alkylene group which may have a substituent;

R 2a represents a substituent selected from the group consisting of a hydrogen atom, a (C1-C6) acyl group, and a (C1-C6) alkoxycarbonyl group;

R 3a includes one or more bonding residues of one or more hydrophobic substituents selected from the group consisting of a linear, branched or cyclic (C1-C30) alkoxy group which may have a substituent, a linear, branched or cyclic (C1-C30) alkylamino group which may have a substituent, a linear, branched or cyclic (C1-C30) dialkylamino group which may have a substituent, a (C1-C8) alkylaminocarbonyl-(C1-C8) alkylamino group which may have a substituent, a bonding residue of a physiologically active substance having a hydroxy group and/or an amino group, and a bonding residue of a fluorescent substance having a hydroxy group and/or an amino group, while the remaining part is a hydroxy group;

Ba represents a single bond or a divalent bonding group;

na represents 1 or 2;

x1a, x2a, and za each independently represent an integer from 0 to 20;

x1a+x2a represents an integer from 1 to 20;

(x1a+x2a+za) represents an integer from 3 to 20; and

respective constituent units having Ria bonded thereto, and a constituent unit formed by intramolecular cyclization of a side-chain carbonyl group constitute a structure with those constituent units being each independently randomly arranged;

wherein the hydrophilic polymer segment has a target binding site bonded thereto, and the main chain polymer combining the polyethylene glycol chain and the polyamino acid chain has a molecular weight of not less than 2 kilodaltons and not more than 7 kilodaltons; and

wherein the block copolymer (C) being a block copolymer having a hydrophilic polymer segment containing a polyethylene glycol chain linked to a hydrophobic polymer segment containing a polyamino acid chain having a physiologically active substance with a hydroxy group and/or an amino group bonded to a side-chain carboxy group;

wherein the block copolymer (C) is represented by General Formula (3):

wherein

R 5c represents a hydrogen or a (C1-C6) alkyl group which may have a substituent;

tc represents an integer from 20 to 140;

Ac represents a (C1-C6) alkylene group which may have a substituent;

R 2c represents a substituent selected from the group consisting of a hydrogen atom, a (C1-C6) acyl group, and a (C1-C6) alkoxycarbonyl group;

R 3c represents a bonding residue of a physiologically active substance having a hydroxy group and/or an amino group;

R 4c is a bonding residue of a hydrophobic substituent and represents one or more substituents selected from the group consisting of a linear, branched or cyclic (C1-C30) alkoxy group which may have a substituent, a linear, branched or cyclic (C1-C30) alkylamino group which may have a substituent, a linear, branched or cyclic (C1-C30) dialkylamino group which may have a substituent, a (C1-C8) alkylaminocarbonyl-(C1-C8) alkylamino group which may have a substituent, a bonding residue of a fluorescent substance having a hydroxy group and/or an amino group, and a hydroxy group;

Bc represents a single bond or a divalent bonding group;

nc represents 1 or 2;

x1c, x2c, y1c, y2c, and zc each independently represent an integer from 0 to 20;

(x1c+x2c) is an essential configuration and represents an integer from 1 to 20;

(x1c+x2c+y1c+y2c+zc) represents an integer from 3 to 20; and

the respective constituent units having R 3c and R 4c bonded thereto, and a constituent unit formed by intramolecular cyclization of a side-chain carbonyl group constitute a structure with those constituent units being each independently randomly arranged; and

wherein the main chain polymer of the block copolymer (C) combining the polyethylene glycol chain and the polyamino acid chain has a molecular weight of not less than 2 kilodaltons and not more than 7 kilodaltons, and a mass content percentage of the physiologically active substance with a hydroxy group and/or an amino group in the block copolymer (C) is not less than 5% by mass and not more than 60% by mass.

2. The composition according to claim 1 , wherein the composition comprising the block copolymer (A) and the block copolymer (C) forms nanoparticles in an aqueous solution, and the nanoparticles have an average particle size of 30 nanometers or less.

3. A medicine comprising the composition according to claim 1 .