Branched polymers and their conjugates

• US 20030143596A1
• Filed: 11/07/2002
• Published: 07/31/2003
• Est. Priority Date: 11/07/2001
• Status: Active Grant

• Current Assignee: Nektar Therapeutics Incorporated
• Original Assignee: Shearwater Corp. (Nektar Therapeutics)
• Inventors: Bentley, Michael David, Zhao, Xuan, Shen, Xiaoming, Battle, William Dudley III
• Granted Patent: US 7,026,440 B2
• Time in Patent Office: Days
• US Class Current: 435/6
• CPC Class Codes: A61K 47/60 the organic macromolecular compound being a polyoxyalkylene oligomer, polymer or dendrimer, e.g. PEG, PPG, PEO or polyglycerol
• CPC Class Codes: A61K 47/6901 Conjugates being cells, cell fragments, viruses, ghosts, red blood cells or viral vectors
• CPC Class Codes: C07K 17/08 the carrier being a synthetic polymer
• CPC Class Codes: C08G 65/329 with organic compounds
• CPC Class Codes: C08G 65/3322 acyclic
• CPC Class Codes: C08G 65/48 Polymers modified by chemical after-treatment
• CPC Class Codes: C08L 2203/02 for biomedical use
• CPC Class Codes: C12N 9/96 Stabilising an enzyme by forming an adduct or a composition; Forming enzyme conjugates

Abstract

The present invention is directed to branched reactive water-soluble polymers comprising at least two polymer arms, such as poly(ethylene glycol), attached to a central aliphatic hydrocarbon core molecule through heteroatom linkages. The branched polymers bear at least one functional group for reacting with a biologically active agent to form a biologically active conjugate. The functional group of the branched polymer can be directly attached to the aliphatic hydrocarbon core or via an intervening linkage, such as a heteroatom, -alkylene-, —O-alkylene-O—, -alkylene-O-alkylene-, -aryl-O—, —O— aryl-, (—O-alkylene-)_m, or (-alkylene-O—)m linkage, wherein m is 1-10.

Claims

1. A branched reactive polymer having the structure:

Y—

(X)p-R(—

X′

-POLY)_q

wherein;

R is an aliphatic hydrocarbon having a length of at least three carbon atoms;

each POLY is a water soluble and non-peptidic polymer;

X′

is a heteroatom linkage;

X is a linker;

p is 0 or 1;

q is 2 to about 10; and

Y is a functional group.

2. The branched polymer of claim 1, wherein X′

is —

NH—

, —

O—

or —

S—

.

3. The branched polymer of claim 1, wherein q is 2 to about 5.

4. The branched polymer of claim 1, wherein the POLY polymer arms are symmetrically located on the aliphatic hydrocarbon.

5. The branched polymer of claim 1, wherein R comprises from 3 to about 7 carbon atoms.

6. The branched polymer of claim 1, wherein R comprises three carbon atoms.

7. The branched polymer of claim 1, wherein each POLY polymer arm and the Y functional group are attached to different carbon atoms of R.

8. The branched polymer of claim 1, wherein each POLY has the structure Z-POLY-, wherein Z is a capping group or a functional group.

9. The branched polymer of claim 8, wherein each Z is a capping group independently selected from the group consisting of alkoxy, alkyl, benzyl, aryl, and aryloxy.

10. The branched polymer of claim 8, wherein each Z is methoxy.

11. The branched polymer of claim 8, wherein each Z is a functional group independently selected from the group consisting of hydroxyl, active ester, active carbonate, acetal, aldehyde, aldehyde hydrate, alkenyl, acrylate, methacrylate, acrylamide, active sulfone, amine, hydrazide, thiol, alkanoic acid, acid halide, isocyanate, isothiocyanate, maleimide, vinylsulfone, dithiopyridine, vinylpyridine, iodoacetamide, epoxide, glyoxal, dione, mesylate, tosylate, and tresylate.

12. The branched polymer of claim 1, wherein Y selected from the group consisting of hydroxyl, active ester, active carbonate, acetal, aldehyde, aldehyde hydrate, alkenyl, acrylate, methacrylate, acrylamide, active sulfone, amine, hydrazide, thiol, alkanoic acid, acid halide, isocyanate, isothiocyanate, maleimide, vinylsulfone, dithiopyridine, vinylpyridine, iodoacetamide, epoxide, glyoxal, dione, mesylate, tosylate, and tresylate.

13. The branched polymer of claim 1, wherein each POLY is independently selected from the group consisting of poly(alkylene glycol), poly(oxyethylated polyol), poly(olefinic alcohol), poly(vinylpyrrolidone), poly(hydroxyalkylmethacrylamide), poly(hydroxyalkylmethacrylate), poly(saccharides), poly(α

-hydroxy acid), poly(vinyl alcohol), polyphosphazene, polyoxazoline, poly(N-acryloylmorpholine), and copolymers, terpolymers, and mixtures thereof.

14. The branched polymer of claim 1, wherein each POLY is poly(ethylene glycol).

15. The branched polymer of claim 1, wherein each POLY is linear or branched.

16. The branched polymer of claim 1, wherein p is 1 and X is selected from the group consisting of a heteroatom, -alkylene-, —

O-alkylene-O—

, -alkylene-O-alkylene-, -aryl-O—

, —

O-aryl-, (—

O-alkylene-)_m, and (-alkylene-O—

)_m, wherein m is 1-10.

17. The branched polymer of claim 1, wherein p is 0 and Y is hydroxyl.

18. The branched polymer of claim 1, wherein Y is protected hydroxyl having the structure —

O-Gp, wherein Gp is a protecting group.

19. The branched polymer of claim 18, wherein Gp is selected from the group consisting of benzyl, acetal and dihydropyranyl.

20. The branched polymer of claim 1, having the structure:

21. A biologically active conjugate, comprising a biologically active molecule covalently attached to a branched reactive polymer of claim 1.

22. A biologically active conjugate comprising a branched polymer covalently attached to a biologically active molecule, wherein the conjugate has the structure:

D-L₁-(X)p-R(-X′

-POLY)_q

wherein;

D is the biologically active molecule;

L₁ is a linkage resulting from the reaction of a functional group of the branched polymer and a functional group of the biologically active molecule;

R is an aliphatic hydrocarbon having a length of at least three carbon atoms;

each POLY is a water soluble and non-peptidic polymer;

X′

is a heteroatom linkage;

X is a linker;

p is 0 or 1; and

q is 2 to about 10.

23. The biologically active conjugate of claim 22, wherein D is selected from the group consisting of peptides, proteins, enzymes, small molecule drugs, dyes, lipids, nucleosides, nucleotides, oligonucleotides, polynucleotides, nucleic acids, polysaccharides, steroids, cells, viruses, liposomes, microparticles, micelles, fats, and electrolytes.

24. The biologically active conjugate of claim 22, having the structure:

25. A nucleophile-substituted aliphatic hydrocarbon core molecule having the structure:

Y′

—

(X)p-R(-Nu)_q

wherein;

Y′

is a protected functional group;

each Nu is a nucleophile;

R is an aliphatic hydrocarbon having a length of at least three carbon atoms;

X is a linker;

p is 0 or 1; and

q is 2 to about 10.

26. The aliphatic hydrocarbon of claim 25, wherein each Nu is amino, thiol, or hydroxyl.

27. The aliphatic hydrocarbon of claim 25, wherein Y′

is a protected hydroxyl.

28. The aliphatic hydrocarbon of claim 25, having the structure:

29. A method of preparing a branched poly(alkylene glycol) polymer, comprising:

providing an aliphatic hydrocarbon substituted with at least two nucleophilic groups and at least one protected functional group;

polymerizing alkylene oxide monomer units onto the aliphatic hydrocarbon at the site of the nucleophilic groups to form at least two poly(alkylene glycol) polymers attached to the aliphatic hydrocarbon via heteroatom linkages;

end-capping the poly(alkylene glycol) polymers with an alkyl group to form alkoxy-terminated polymers; and

deprotecting the protected functional group to form a hydroxyl group.

30. The method of claim 29, wherein the aliphatic hydrocarbon has the structure:

31. The method of claim 29, wherein the alkylene oxide monomer units are units of ethylene oxide.

32. The method of claim 29, wherein the protected functional group is a protected hydroxyl group and said deprotecting step comprises hydrolysis or hydrogenolysis of the protected hydroxyl group.

33. The method of claim 29, wherein said end-capping step comprises end-capping the polymers with methoxy.

34. The method of claim 29, wherein the aliphatic hydrocarbon is selected from the group consisting of 2-benzyloxy-1,3-propanediol, 2-benzyloxyethoxy-1,3-propanediol, and 2-benzyloxyethoxyethyl-1,3-propanediol.

35. The method of claim 29, further comprising modifying the deprotected functional group to form a second functional group.

36. The method of claim 35, wherein the second functional group is selected from the group consisting of active ester, active carbonate, acetal, aldehyde, aldehyde hydrate, alkenyl, acrylate, methacrylate, acrylamide, active sulfone, amine, hydrazide, thiol, alkanoic acid, acid halide, isocyanate, isothiocyanate, maleimide, vinylsulfone, dithiopyridine, vinylpyridine, iodoacetamide, epoxide, glyoxal, dione, mesylate, tosylate, and tresylate.