Nucleic acid delivery composition and carrier composition, pharmaceutical composition using the same, and method for nucleic acid delivery

A carrier composition for delivering a nucleic acid to a target cell or tissue, comprising:

• a block copolymer having an uncharged hydrophilic polymer segment and a cationic polymer segment;
• and a second cationic polymer,
• wherein the uncharged hydrophilic polymer segment of the block copolymer is a polyalkylene glycol segment, the cationic polymer segment of the block copolymer is a segment made of poly(amino acid) having amino groups at its side chains, and the second cationic polymer is poly(amino acid) having amino groups at its side chains, and
• wherein the mol percentage (B/H ratio) of the cationic groups of the block copolymer to the total cationic groups of the block copolymer and the second cationic polymer is between 25% and 90%,
• wherein said block copolymer is selected from the group consisting of formulae (I) to (IV):
• wherein, in formulae (I) and (II),
• R1 represents a hydrogen atom or unsubstituted or substituted, linear or branched C1-12 alkyl group,
• R2 represents a methylene group or ethylene group,
• R3 represents a hydrogen atom, protecting group, hydrophobic group or polymerizable group,
• R4 is either the same as R5 or represents an initiator residue,
• R5 respectively and independently represent a hydroxyl group, oxybenzyl group or —NH—(CH2)a—X group, provided that 85% or more of R5 are —NH—(CH2)a—X groups,
• X respectively and independently represents a bulky amine compound residue having a pKa value of 7.4 or less, an amine compound residue containing one type or two or more types of a primary, secondary, tertiary or quaternary amine, or a non-amine compound residue,
• L1 and L2 respectively and independently represent a linking group,
• a represents an integer of 1 to 5,
• m represents an integer of 5 to 20,000,
• n represents an integer of 2 to 5,000, and
• x represents an integer of 0 to 5,000, provided that x is not greater than n;
• wherein, in formulae (III) and (IV),
• R1 represents a hydrogen atom or unsubstituted or substituted, linear or branched C1-12 alkyl group,
• R2 represents a methylene group or ethylene group,
• R3 represents a hydrogen atom, protecting group, hydrophobic group or polymerizable group,
• R4 is either the same as R5 or represents an initiator residue,
• R5 respectively and independently represent a hydroxyl group, oxybenzyl group or —NH—(CH2)a—X group, provided that 85% or more of R5 are —NH—(CH2)a—X groups,
• X respectively and independently represents a bulky amine compound residue having a pKa value of 7.4 or less, an amine compound residue containing one type or two or more types of a primary, secondary, tertiary or quaternary amine, or a non-amine compound residue,
• L1 and L2 respectively and independently represent a linking group,
• a represents an integer of 1 to 5,
• R6 respectively and independently represents a hydrogen atom or protecting group,
• m represents an integer of 5 to 20,000,
• n represents an integer of 2 to 5,000,
• y represents an integer of 0 to 5,000 and
• z represents an integer of 0 to 5,000, provided that y+z is not greater than n;
• and
• wherein said second cationic polymer is selected from the group consisting of formulae (I′) to (IV′):
• wherein, in formulae (I′) and (II′), R2, R3, R4, R5, n and x have the same meanings as defined in formulae (I) and (II);
• wherein, in formulae (III′) and (IV′), R2, R3, R4, R5, R6, n, x, y and z have the same meanings as defined in formulae (III) and (IV).