Patent ID: 7829657

Claim:
A composition for the delivery of nucleic acid to target cells or tissues, which comprises a polycationically charged polymer as a carrier of nucleic acid and a nucleic acid, wherein the polycationically charged polymer is a polymer of formula (III) or its salt: wherein: R 10 denotes hydroxyl group, oxybenzyl group or a group of —NH—R 11 wherein R 11 denotes unsubstituted or substituted with a substituent selected from the group consisting of acetalized formyl group, cyano group, formyl group, carboxyl group, amino group, C 1-6 alkoxylcarbonyl group, C 2-7 acylamide group, tri (same or different)-C 1-6 alkylsiloxy group, siloxy group and silylamino group straight chain or branched C 1-20 alkyl group; R 2a and R 2b independently denote methylene group or ethylene group; R 3 denotes hydrogen atom, protecting group, hydrophobic group or polymerizable group; R 5a and R 5b independently denote hydroxyl group, oxybenzyl group or a group of —NH—(CH 2 ) a —X wherein a denotes an integer of 1 to 5, and X's independently denote either a residue of amine compound which contains at least one species of primary, secondary, tertiary or quaternary ammonium salt or a residue of compound other than amine, with the proviso that, among the total of R 5a and R 5b , there are at least two —NH—(CH 2 ) a —X groups wherein X denotes (NH(CH 2 ) 2 ) c —NH 2 and e denotes an integer of 1 to 5; R 6a 's independently denote hydrogen atom or a protecting group selected from the group consisting of Z-group, Boc-group, acetyl group and trifluoroacetyl group which are usually employed as a protecting group for amino group; n denotes an integer of 2 to 5,000; y denotes an integer of 0 to 5,000; and z denotes an integer of 0 to 5,000, with the proviso that y+z is not larger than n, wherein the recurring units in formula (III) may be present in a random order or in the specific order of the formula; and wherein an N/P ratio is 10 to 80.