Unit structure-type pharmaceutical composition for nucleic acid delivery

Patent metadata

Field	Value
Publication number	US-9808480-B2
Application number	US-201314395745-A
Country	US
Kind code	B2
Filing date	Apr 30, 2013
Priority date	Apr 27, 2012
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

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).

First claim

The invention claimed is:

1. A unit structure, consisting of:
a single double-stranded nucleic acid having 18 to 30 base pairs, and
two block copolymers, each having a cationic polyamino acid segment and a 2-arm branched hydrophilic polymer chain segment,
wherein:
(i) a difference between a total of positive charges derived from cationic groups of the cationic polyamino acid segments and a total of negative charges derived from the nucleic acid in the unit structure falls within a range of ±10% of the total of the negative charges derived from the nucleic acid,
(ii) the 2-arm branched hydrophilic polymer chain segment comprises two polyethylene glycol chains, each polyethylene glycol chain having a molecular weight of 20,000 Da or more,
(iii) each of the polyethylene glycol chains has a radius of inertia (Rg) equal to or longer than half the length of the nucleic acid, and
(iv) the cationic polyamino acid segments are bound to the nucleic acid via electrostatic bonds.

2. The unit structure according to claim 1 , wherein
all cationic amino acids in the cationic polyamino acid segment have only one cationic group in each side chain.

3. The unit structure according to claim 1 , wherein
the cationic polyamino acid segment contains exclusively cationic amino acid residues.

4. The unit structure according to claim 1 , wherein
the nucleic acid is siRNA.

5. The unit structure according to claim 4 , wherein
the polyamino acid chain segment of each block copolymer contains a number of positive charges that is at least approximately one-half of the total of the negative charges derived from the nucleic acid.

6. The unit structure according to claim 4 , wherein
each of the polyethylene glycol chains has a molecular weight of 20,000 Da to 60,000 Da.

7. A unit structure, consisting of one siRNA and two block copolymers, wherein
(i) each block copolymer has a cationic polyamino acid segment and a 2-arm branched polyethylene glycol at one terminal of the polyamino acid chain segment,
(ii) each of the arms of the polyethylene glycol has a molecular weight of from 20,000 Da to 80,000 Da,
(iii) a difference between a total of positive charges derived from cationic groups of the cationic polyamino acid segments and a total of negative charges derived from the siRNA in the unit structure falls within a range of ±10% of the total of the negative charges derived from the siRNA, and
(iv) the cationic polyamino acid segments are bound to the siRNA via electrostatic bonds.

8. The unit structure according to claim 7 , wherein
all cationic amino acids in the cationic polyamino acid segment have only one cationic group in each side chain.

9. The unit structure according to claim 7 , wherein
the cationic polyamino acid segment contains exclusively cationic amino acid residues.

10. The unit structure according to claim 7 , wherein the two block copolymers are each selected from the group consisting of the following formulae (1)-(2):

wherein:
R 1a to R 1d are each independently a hydrogen atom, an unsubstituted or substituted linear or branched alkyl group having 1 to 12 carbon atoms, or a group represented by the following formula (I):

where k represents an integer of from 1 to 5, and D represents a target binding site;
R 2 is a hydrogen atom, an unsubstituted or substituted linear or branched alkyl group having 1 to 12 carbon atoms, or an unsubstituted or substituted linear or branched alkylcarbonyl group having 1 to 24 carbon atoms;
R 3 is a hydroxyl group, an unsubstituted or substituted linear or branched alkyloxy group having 1 to 12 carbon atoms, an unsubstituted or substituted linear or branched alkenyloxy group having 2 to 12 carbon atoms, an unsubstituted or substituted linear or branched alkynyloxy group having 2 to 12 carbon atoms, or an unsubstituted or substituted linear or branched alkyl-substituted imino group having 1 to 12 carbon atoms;
R 4a and R 4b are each independently a methylene group or an ethylene group;
R 5a and R 5b are the same group or different groups selected from the group consisting of:
—NH—(CH 2 ) p1 —[NH—(CH 2 ) q1 —] r1 NH 2   (i);

—NH—(CH 2 ) p2 —N[—(CH 2 ) q2 —NH 2 ] 2   (ii);

—NH—(CH 2 ) p3 —N{[—(CH 2 ) q3 —NH 2 ][—(CH 2 ) q4 —NH—] r2 H}  (iii); and

—NH—(CH 2 ) p4 —N{—(CH 2 ) q5 —N[—(CH2) q6 -NH 2 ] 2 } 2   (iv),

where p1 to p4, q1 to 6, and r1 to 2 are each independently an integer of from 1 to 5;
Q is —NH 2 , —NHC(═NH)NH 2 , or a group represented by the following formula (II);

L is a divalent linking group or a valence bond;
x1 to x4 are each independently an integer of from 454 to 1818;
y, z, and v are each independently an integer of from 0 to 30, provided that y, z, and v satisfy the relationship 18≦y+z+v≦30;
w is an integer of from 1 to 6;
1 and m are each independently an integer of from 0 to 5; and
n is 1.

11. The unit structure according to claim 10 , wherein x1 to x4 are each independently an integer of from 454 to 1200.

12. The unit structure according to claim 11 , wherein:
the siRNA is a double-stranded RNA having 21 base pairs and
y, z, and v are selected such that the number of cationic groups in the cationic polyamino acid segment is an integer of from 18 to 22.

13. A method of treating cancer, comprising:
administering a therapeutically effective amount of the unit structure according to claim 1 to a patient in need thereof.

14. A method of treating cancer, comprising:
administering a therapeutically effective amount of the unit structure according to claim 7 to a patient in need thereof.

15. The unit structure according to claim 1 , each polyethylene glycol chain has a molecular weight of from 30,000 Da to 60,000 Da.

16. The unit structure according to claim 7 , each strand of the polyethylene glycol has a molecular weight of from 30,000 Da to 60,000 Da.

Assignees

• Univ Tokyo
• Nanocarrier Co Ltd

Inventors

• Kataoka Kazunori
• Miyata Kanjiro
• Nishiyama Nobuhiro
• Osada Kensuke
• Watanabe Sumiyo
• Fukushima Shigeto
• Chaya Hiroyuki
• Takemoto Hiroyasu
• Kato Yasuki

Classifications

• A61K47/6455

  Polycationic oligopeptides, polypeptides or polyamino acids, e.g. for complexing nucleic acids · CPC title

• A61K47/56

  the modifying agent being an organic macromolecular compound, e.g. an oligomeric, polymeric or dendrimeric molecule · CPC title

• A61K47/62

  the modifying agent being a protein, peptide or polyamino acid · CPC title

• A61K47/48215

  Human Necessities · mapped topic

• A61K9/0019

  Injectable compositions; Intramuscular, intravenous, arterial, subcutaneous administration; Compositions to be administered through the skin in an invasive manner (non-active ingredients are additionally classified in A61K47/00) · CPC title