# US 9,034,348 B2 · Injectable chitosan mixtures forming hydrogels

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 9,034,348 B2
- Document ID: US9034348B2
- Status: Granted
- Kind: B2
- Application number: 13/830,268
- Filed: 2013-03-14
- Published: 2013-09-19
- Granted: 2015-05-19
- Earliest claimed: 2006-12-11
- Assignees: Chi2Gel Ltd.
- Applicants: CHI2GEL Ltd.
- Inventors: Noah Ben-Shalom; Zvi Nevo; Abraham Patchornik; Dror Robinson
- Web page: https://patentgrep.com/patent/US9034348B2

## CPC

- A61K 31/722: Chitin, chitosan
- A61K 8/042: {Gels}
- A61K 8/736: {Chitin; Chitosan; Derivatives thereof}
- A61K 9/0009: {involving or responsive to electricity, magnetism or acoustic waves; Galenical aspects of sonophoresis, iontophoresis, electroporation or electroosmosis}
- A61K 9/0014: {Skin, i.e. galenical aspects of topical compositions (non-active ingredients are additionally classified in A61K47/00; A61K9/0009, A61K9/0021, A61K9/7015, A61K9/7023 take precedence; cosmetic preparations A61K8/00, A61Q; preparations for wound dressings or bandages A61L26/00)}
- A61K 9/0024: {Solid, semi-solid or solidifying implants, which are implanted or injected in body tissue (compositions for intravenous administration, normal injectable solutions or dispersions for, e.g. subcutaneous administration A61K9/0019; brain implants A61K9/0085; (coated) prostheses, catheters or stents A61L)}
- A61K 9/06: Ointments; Bases therefor; {Other semi-solid forms, e.g. creams, sticks, gels (composition of ointments, creams or gels A61K47/00)}
- A61K 31/738: Cross-linked polysaccharides
- A61K 47/36: Polysaccharides; Derivatives thereof, e.g. gums, starch, alginate, dextrin, hyaluronic acid, chitosan, inulin, agar or pectin
- A61L 26/0023: {Polysaccharides}
- A61L 26/008: {Hydrogels or hydrocolloids}
- A61L 26/009: {Materials resorbable by the body}
- A61L 27/20: Polysaccharides
- A61L 27/3804: {characterised by specific cells or progenitors thereof, e.g. fibroblasts, connective tissue cells, kidney cells}
- A61L 27/52: Hydrogels or hydrocolloids
- A61L 27/60: Materials for use in artificial skin
- A61Q 19/00: Preparations for care of the skin
- C08J 3/075: Macromolecular gels
- C08L 5/08: Chitin; Chondroitin sulfate; Hyaluronic acid; Derivatives thereof
- A61K 2800/594: Mixtures of polymers
- A61K 2800/805: Corresponding aspects not provided for by any of codes A61K2800/81 - A61K2800/95
- A61K 2800/91: Injection
- A61L 2300/412: Tissue-regenerating or healing or proliferative agents
- A61L 2400/06: Flowable or injectable implant compositions
- A61L 2430/06: for cartilage reconstruction, e.g. meniscus
- A61Q 19/08: Anti-ageing preparations
- C08J 2305/08: Chitin; Chondroitin sulfate; Hyaluronic acid; Derivatives thereof
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)
- A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K)
- A61Q: SPECIFIC USE OF COSMETICS OR SIMILAR TOILETRY PREPARATIONS
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)

## Abstract

A chitosan composition which forms a hydrogel at near physiological pH and 37° C., comprising at least one type of chitosan having a degree of acetylation in the range of from about 30% to about 60%, and at least one type of chitosan having a degree of deacetylation of at least about 70% is disclosed. Further disclosed is a chitosan composition which forms a hydrogel at near physiological pH and 37° C., that includes at least one type of chitosan having a degree of deacetylation of at least about 70% and a molecular weight of from 10-4000 kDa, and at least one type of a chitosan having a molecular weight of from 200-20000 Da. Further disclosed are methods of preparation and uses of the chitosan compositions.

## Claims

### Claim 1

A chitosan composition which forms a hydrogel at near physiological pH and at 37° C., comprising at least one acetylated chitosan having a degree of acetylation in the range of from about 30% to about 60%, and at least one deacetylated chitosan having a degree of deacetylation that is about 70% to about 95%, the composition being in the form of an aqueous solution at neutral pH, wherein the ratio of said acetylated chitosan to said deacetylated chitosan in the composition is in the range of 1:1 to 4:1.

### Claim 2 (depends on 1)

The chitosan composition of claim 1, further comprising at least one negatively charged polysaccharide.

### Claim 3 (depends on 2)

The chitosan composition of claim 2, wherein the negatively charged polysaccharide is hyaluronic acid.

### Claim 4 (depends on 1)

The chitosan composition of claim 1, further comprising acetylglucosamine oligomers.

### Claim 5 (depends on 4)

The chitosan composition of claim 4, wherein the acetylglucosamine oligomers comprise Tri-N-acetyl-glucosamine.

### Claim 6 (depends on 4)

The chitosan composition of claim 4, wherein the acetylglucosamine oligomers are present in the composition at a concentration of between 0.05% to 10% w/v.

### Claim 7 (depends on 1)

The chitosan composition of claim 1, further comprising a cross-linking agent in an amount sufficient to accelerate gelation of the chitosan composition.

### Claim 8 (depends on 7)

The chitosan composition of claim 7, wherein said cross-linking agent is capable of cross-linking the amine or hydroxyl residues of the chitosans.

### Claim 9 (depends on 7)

The chitosan composition of claim 7, wherein said amount of the cross linking agent is in the range of between 0.1% to 2% w/v.

### Claim 10 (depends on 7)

The chitosan composition of claim 7, wherein the cross-linking agent is added to the chitosan composition prior to introducing said chitosan composition into a site in vivo.

### Claim 11 (depends on 7)

The chitosan composition of claim 7, wherein the cross-linking agent is genipin.

### Claim 12

A process for preparing a stable pH-dependent and temperature-dependent chitosan hydrogel composition comprised of at least one acetylated chitosan having a degree of acetylation of from about 30% to about 60%, and at least one deacetylated chitosan having a degree of deacetylation that is about 70% to about 95%, which process comprises:
d) dissolving said acetylated chitosan and said deacetylated chitosan in an acidic aqueous solution at a temperature between 0° C. to 10° C., to thereby form a composite solution, wherein the ratio of said acetylated chitosan and said deacetylated chitosan in said composite solution is in the range of 1:1 to 4:1;
e) adjusting the pH of said composite solution to a value of 6.6 to 7.4 at a temperature between 0° C. to 10° C.; and
f) increasing at least one of the temperature of said composite solution to about 37° C. and/or raising the pH to physiological pH.

### Claim 13 (depends on 12)

The process of claim 12, further comprising adding a negatively charged polysaccharide to the composition before step c.

### Claim 14 (depends on 13)

The process of claim 13 wherein the polysaccharide is hyaluronic acid.

### Claim 15 (depends on 12)

The process of claim 12, further comprising adding acetylglucosamine oligomers to the composition.

### Claim 16 (depends on 12)

The process of claim 12, further comprising adding a cross-linking agent in an amount sufficient to accelerate gelation of the chitosan composition, wherein the cross-linking agent is added to the composition prior to introducing said chitosan composition into a site in vivo.

### Claim 17 (depends on 16)

The process of claim 16 wherein the cross-linking agent is genipin.

### Claim 18 (depends on 12)

A hydrogel chitosan composition formed by the process of claim 12.

### Claim 19

A method of treating medical condition in a subject in need thereof, comprising applying into a site of the medical condition a chitosan composition comprising at least one acetylated chitosan having a degree of acetylation in the range of from about 30% to about 60%, and at least one deacetylated chitosan having a degree of deacetylation that is about 70% to about 95%, the composition being in the form of an aqueous solution at neutral pH, wherein the ratio of said acetylated chitosan to said deacetylated chitosan in the solution is in the range of 1:1 to 4:1.

### Claim 20 (depends on 19)

The method of claim 19, wherein the medical condition is selected from the group consisting of: osteoarthritis, fracture repair, bone structural support, cartilage repair, intervertebral disc repair, meniscal repair, bone reconstruction, bone filling and synovial fluid replacement.

### Claim 21

A kit for producing a chitosan hybrid hydrogel, comprising:
(i) a container containing a chitosan composition comprising at least one acetylated chitosan having a degree of acetylation in the range of from about 30% to about 60%, and at least one deacetylated chitosan having a degree of deacetylation that is about 70% to about 95%, wherein the ratio of said acetylated chitosan to said deacetylated chitosan in the solution is in the range of 1:1 to 4:1;
(ii) a container containing a cross-linking agent in an amount sufficient to accelerate gelation of the chitosans; and
(iii) instructions for preparing the chitosan hybrid hydrogel.

### Claim 22 (depends on 21)

The kit of claim 21, wherein the container containing a chitosan composition further comprises a negatively charged polysaccharide.

### Claim 23 (depends on 22)

The kit of claim 22, wherein the polysaccharide is hyaluronic acid.

### Claim 24 (depends on 21)

The kit of claim 21, wherein the container containing a chitosan composition further comprises acetylglucosamine oligomers.

### Claim 25 (depends on 24)

The kit of claim 24, wherein the acetyl glucosamine oligomers comprise Tri-N-acetyl-glucosamine.

### Claim 26 (depends on 21)

The kit of claim 21, wherein the kit further comprises a container containing a solvent for dissolving the cross-linking agent.