Microgel particles for the delivery of bioactive materials

• US 20060223776A1
• Filed: 03/24/2006
• Published: 10/05/2006
• Est. Priority Date: 03/29/2002
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Murthy, Niren, Frechet, Jean M.J.
• Granted Patent: US 7,683,041 B2
• Time in Patent Office: Days
• US Class Current: 514/44.R
• CPC Class Codes: A61K 2039/53 DNA (RNA) vaccination
• CPC Class Codes: A61K 2039/55555 Liposomes; Vesicles, e.g. nanoparticles; Spheres, e.g. nanospheres; Polymers
• CPC Class Codes: A61K 31/70 Carbohydrates; Sugars; Derivatives thereof sorbitol A61K31/047
• CPC Class Codes: A61K 39/39 characterised by the immunostimulating additives, e.g. chemical adjuvants
• CPC Class Codes: A61K 9/1635 obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyvinyl pyrrolidone, poly(meth)acrylates
• CPC Class Codes: A61K 9/1652 Polysaccharides, e.g. alginate, cellulose derivatives; Cyclodextrin homeopathic globules A61K9/1623
• CPC Class Codes: A61K 9/5161 Polysaccharides, e.g. alginate, chitosan, cellulose derivatives; Cyclodextrin
• CPC Class Codes: A61K 9/5192 Processes
• CPC Class Codes: B82Y 5/00 Nanobiotechnology or nanomedicine, e.g. protein engineering or drug delivery
• CPC Class Codes: C08B 37/0021 Dextran, i.e. (alpha-1,4)-D-glucan; Derivatives thereof, e.g. Sephadex, i.e. crosslinked dextran

Abstract

Novel microgels, microparticles and related polymeric materials capable of delivering bioactive materials to cells for use as vaccines or therapeutic agents. The materials are made using a crosslinker molecule that contains a linkage cleavable under mild acidic conditions. The crosslinker molecule is exemplified by a bisacryloyl acetal crosslinker. The new materials have the common characteristic of being able to degrade by acid hydrolysis under conditions commonly found within the endosomal or lysosomal compartments of cells thereby releasing their payload within the cell. The materials can also be used for the delivery of therapeutics to the acidic regions of tumors and sites of inflammation.

Claims

1-22. -22. (canceled)

23. A method of delivering a bioactive material to the cellular interior of a cell to control immune response, comprising:

providing to the cell a microgel composition comprising;

(a) a bisacryloyl acetal crosslinker-linked polymer, wherein said bisacryloyl acetal crosslinker being essentially non-hydrolyzable above pH 7, but hydrolyzable below pH 6, and

(b) a bioactive material,

whereby hydrolysis within an acidic cellular compartment of the cell cleaves said crosslinker and releases said bioactive material.

24. The method of claim 23 wherein said bioactive material is selected from the group consisting of polysaccharides, amino acids, peptides proteins, DNA, RNA, antigens, antibodies, interleukins, anticancer agents, antitumor agents, and vaccines.

25. The method of claim 23 wherein said bioactive material is conjugated to, physically entrapped within or adsorbed onto the microgel composition.

26. The method of claim 23 wherein said bisacryloyl acetal crosslinker has the formula R²CH(OR¹)₂,

wherein R¹ is an acryloyl group;

and

R² is Ar—

X where X is a water solubilizing group selected from hydrogen, methoxy, —

O—

(CH₂—

CH₂—

O)_n—

CH₃ wherein n is from 1 to 10, -), —

O—

CH₂—

CH₂—

O—

C(O)—

O-Ph-NO₂ and O—

CH₂—

CH₂—

CH₂—

NH—

CO-(dextran polysaccharide), said dextran polysaccharide having a molecular weight from 300 to 100,000 daltons; and

Ar is an aryl group and wherein said crosslinker hydrolyzes at pH 4.5 to pH 7.4;

wherein said polymer has a particle size between 0.1-10 microns and cross linkages between 1 and 20 mole percent.

34. The method of claim 23 wherein the cellular compartment is a lysosome or phagolysosome of antigen presenting cells.

35. The method of claim 34 wherein the cellular compartment releases the bioactive material into the cell cytoplasm and is subsequently displayed on the cell surface of antigen presenting cells.

36. The method of claim 35 wherein the displayed bioactive material on the cell activates cytotoxic T lymphocytes and immune response.

37. The method of claim 36 wherein the cytotoxic T-cell lymphocyte activation is at least 50% as compared to minimum levels of cytotoxic T-cell lymphocyte activation.

38. The method of claim 23 wherein said cell exhibits at least 50% viability after 24 hours incubation with said microgel composition.

39. The method of claim 26 wherein the R¹ acryloyl group is selected from the group consisting of:

ethylacrylamide, methylacrylamide, acrylamide, trifluoro acetamide, tribromoacetamide, trichloroacetamide, triiodoacetamide, and ethylamines

40. The method of claim 23 wherein said bisacryloyl acetal crosslinker-linked polymer has at least a 20% loading efficiency of bioactive material.

41. The method of claim 23 wherein said microgel composition further comprises an immunostimulatory group.

42. A method of vaccination, comprising the step of providing to a cell an acid degradable crosslinked microgel composition, wherein the composition comprises:

(a) a polymer backbone selected from the group consisting of an acrylic polymer and a dextran polysaccharide crosslinked by an acid hydrolyzable crosslinker, wherein said crosslinker hydrolyzes at pH 4.5 to pH 7.4;

(b) the crosslinker having the formula R²CH(OR¹)₂, wherein

R¹ is an acryloyl group; and

R² is Ar—

X where X is a water solubilizing group selected from hydrogen, methoxy, —

O—

(CH₂—

CH₂—

O)_n—

CH₃ wherein n is from 1 to 10, —

O—

CH₂—

CH₂—

O—

C(O)—

O-Ph-NO₂ and —

O—

CH₂—

CH₂—

CH₂—

NH—

CO-(dextran polysaccharide), said dextran polysaccharide having a molecular weight from 300 to 100,000 daltons;

and Ar is an aryl group;

(c) a particle size of the microgel composition between 0.1-10 microns;

(d) cross linkages between 1 and 20 mole percent; and

(e) a bioactive material,

whereby hydrolysis cleaves said crosslinker and releases said bioactive material.

43. The method of claim 42 wherein said bioactive material is selected from the group consisting of polysaccharides, amino acids, peptides, proteins, DNA, RNA, antigens, antibodies, interleukins, anticancer agents, antitumor agents, and vaccines.

44. The method of claim 42 wherein said bioactive material is conjugated to, physically entrapped within or adsorbed onto the microgel composition.

45. The method of claim 42 wherein hydrolysis occurs in a lysosome or phagolysosome of antigen presenting cells.

46. The method of claim 45 wherein the lysosome or phagolysosome releases the bioactive material into the cell cytoplasm and the bioactive material is subsequently displayed on the cell surface of antigen presenting cells.

47. The method of claim 46 wherein the displayed bioactive material on the cell activates cytotoxic T lymphocytes and immune response.

48. The method of claim 47 wherein the cytotoxic T-cell lymphocyte activation is at least 50% as compared to minimum levels of cytotoxic T-cell lymphocyte activation.

49. The method of claim 48 wherein said cell exhibits at least 50% viability after 24 hours incubation with said microgel composition.

50. The composition of claim 42 wherein R¹ is ethylacrylamide and R² is such that Ar is phenyl and X is methoxy.

51. The composition of claim 42 wherein R¹ is an acrylate, whereby crosslinker hydrolysis causes generation of further acidic species in an autocatalytic manner.

52. The composition of claim 42 wherein the particle size is between 200 nm and 500 nm.

53. The composition of claim 42 wherein said dextran polysaccharide having a molecular weight from 300 to 100,000 daltons.

54. The composition of claim 42 wherein the bioactive material is selected from the group consisting of polysaccharides, DNA, RNA, amino acids, and proteins.

55. The composition of claim 42 whereby the bioactive material is physically entrapped within the microgel composition.

56. The composition of claim 42 whereby the bioactive material is adsorbed onto the microgel composition.

57. The composition of claim 42 wherein said bioactive material is an antigen.

58. The composition of claim 42 wherein the bioactive material is unmethylated DNA.