The University of Tokyo

Nanocarrier Co., Ltd.

Kawasaki Institute of Industrial Promotion

Sumiyo Watanabe

Kanjiro Miyata

Shigeto Fukushima

Kazunori Kataoka

Nobuhiro Nishiyama

Yasuki Kato

Hiroyasu Takemoto

Kensuke Osada

Hiroyuki Chaya

HyunJin Kim

Kotaro Hayashi

Kazuko Toh

A unit-type polyion complex for use in delivering nucleic acid to a target site in a patient includes one or more molecules of a block copolymer having a poly(ethylene glycol) segment and a cationic poly(amino acid) segment and one or more molecules of a nucleic acid. A total quantity of positive charges derived from side chains of the cationic poly(amino acid) segment of the block copolymer in the unit-type polyion complex is not offset by a total quantity of negative charges derived from the nucleic acid. Furthermore, the nucleic acid has a strand length of 10-50 bases, the molecular weight of the poly(ethylene glycol) segment is 40&#xd7;10or more, and the block copolymer has a binding constant (Ka) for the nucleic acid of 3.0&#xd7;10or more.

Nucleic acid-loaded unit polyion complex

A unit structure-type pharmaceutical composition includes a single nucleic acid, such as an antisense nucleic acid, electrostatically bound to a single block copolymer having a cationic polyamino acid segment and a hydrophilic polymer chain segment. The negative charges of the nucleic acid are counterbalanced, at least substantially, by the positive charges of the cationic polyamino acid segment such that the pharmaceutical composition is electrically neutral or nearly electrically neutral. Further, the nucleic acid is covered with the hydrophilic polymer chain segment. The block copolymer thereby improves the blood retention capability of the nucleic acids.

Unit structure-type pharmaceutical composition for nucleic acid delivery

A unit structure-type pharmaceutical composition includes at least one nucleic acid, such as siRNA, electrostatically bound to at least one block copolymer having a cationic polyamino acid segment and a hydrophilic polymer chain segment. The negative charge(s) of the nucleic acid are counterbalanced, at least substantially, by the positive charge(s) of the cationic polyamino acid segment such that the pharmaceutical composition is electrically neutral or nearly electrically neutral. Further, the nucleic acid is covered with the hydrophilic polymer chain segment(s). The at least one block copolymer thereby improves the blood retention capability of the nucleic acid(s).

Growing community of inventors

Tokyo, Japan

Sumiyo Watanabe