# US 8,153,612 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 8,153,612 B2 - Document ID: US8153612B2 - Status: Granted - Kind: B2 - Application number: 12/155,916 - Filed: 2008-06-11 - Published: 2009-01-01 - Granted: 2012-04-10 - Earliest claimed: 2006-12-11 - Assignees: Chi2Gel Ltd. - Inventors: Noah Ben-Shalom; Zvi Nevo; Abraham Patchornik; Dror Robinson - Web page: https://patentgrep.com/patent/US8153612B2 ## CPC - A61K 47/36: Polysaccharides; Derivatives thereof, e.g. gums, starch, alginate, dextrin, hyaluronic acid, chitosan, inulin, agar or pectin - A23L 29/275: of animal origin, e.g. chitin - 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 9/0019: {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)} - 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 9/0048: {Eye, e.g. artificial tears} - A61K 9/0051: {Ocular inserts or implants} - A61K 9/06: Ointments; Bases therefor; {Other semi-solid forms, e.g. creams, sticks, gels (composition of ointments, creams or gels A61K47/00)} - A61L 15/28: Polysaccharides or their derivatives {(A61L15/225 takes precedence)} - A61L 15/64: specially adapted to be resorbable inside the body - A61L 27/20: Polysaccharides - A61L 27/38: {containing added animal cells (organs or tissue containing native cells A61L27/36)} - A61L 27/52: Hydrogels or hydrocolloids - A61L 27/60: Materials for use in artificial skin - A61P 3/06: Antihyperlipidemics - A61P 7/00: Drugs for disorders of the blood or the extracellular fluid - A61P 17/00: Drugs for dermatological disorders - A61P 17/02: for treating wounds, ulcers, burns, scars, keloids, or the like - A61P 19/00: Drugs for skeletal disorders - 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 2800/91: Injection - A61L 2400/06: Flowable or injectable implant compositions - 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) - A23L: FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES, NOT OTHERWISE PROVIDED FOR; PREPARATION OR TREATMENT THEREOF (preservation thereof A23B) - 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) - A61P: SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS - 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., comprising 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 of at least about 70%, the composition being in a form of an aqueous solution at neutral pH; and 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 2 (depends on 1) The chitosan composition of claim 1, wherein said acetylated chitosan is either homogenously acetylated or homogenously deacetylated. ### Claim 3 (depends on 1) The chitosan composition of claim 1, wherein said deacetylated chitosan is non-homogenously deacetylated. ### Claim 4 (depends on 1) The chitosan composition of claim 1, wherein said acetylated chitosan and said deacetylated chitosan are each independently present at a concentration of from 0.2% to 3% w/v of the total composition. ### Claim 5 (depends on 1) The chitosan composition of claim 1, wherein said acetylated chitosan and said deacetylated chitosan are each independently present at a concentration of from 0.3% to 2% w/v of the total composition. ### Claim 6 (depends on 1) The chitosan composition of claim 1, wherein said acetylated chitosan and said deacetylated chitosan are each independently present at a concentration of from 1% to 1.2% w/v of the total composition. ### Claim 7 (depends on 1) The chitosan composition of claim 1, wherein the ratio of said acetylated chitosan to said deacetylated chitosan is selected from the group consisting of 1:1, 2:1, 3:1 and 4:1. ### Claim 8 (depends on 7) The chitosan composition of claim 7, wherein said ratio is 1:1. ### Claim 9 (depends on 8) The chitosan composition of claim 8, wherein said acetylated chitosan and said deacetylated chitosan are each present at a concentration of from 1% to 1.2% w/v of the total composition. ### Claim 10 (depends on 1) The chitosan composition of claim 1, wherein said acetylated chitosan and said deacetylated chitosan each independently has a molecular weight in the range of from 10 kDa to 4000 kDa. ### Claim 11 (depends on 10) The chitosan composition of claim 10, wherein said deacetylated chitosan has a molecular weight greater than 60 kDa. ### Claim 12 (depends on 10) The chitosan composition of claim 10, wherein said deacetylated chitosan has a molecular weight greater than 200 kDa. ### Claim 13 (depends on 10) The chitosan composition of claim 10, wherein said deacetylated chitosan has a molecular weight greater than 400 kDa. ### Claim 14 (depends on 11) The chitosan composition of claim 11, wherein said acetylated chitosan has a molecular weight of greater than 200 kDa. ### Claim 15 (depends on 10) The chitosan composition of claim 10, wherein said deacetylated chitosan has a molecular weight that ranges from 400 kDa to 700 kDa and said acetylated chitosan has a molecular weight that ranges from 200 kDa to 250 kDa. ### Claim 16 (depends on 15) The chitosan composition of claim 15, wherein said acetylated chitosan and said deacetylated chitosan are each present at a concentration of from 1% to 1.2% w/v of the total composition. ### Claim 17 (depends on 1) The chitosan composition of claim 1, further comprising at least one negatively charged substance which forms a hybrid with said hydrogel. ### Claim 18 (depends on 17) The chitosan composition of claim 17, wherein said at least one negatively charged substance comprises a negatively charged polysaccharide. ### Claim 19 (depends on 18) The chitosan composition of claim 18, wherein said negatively charged polysaccharide is a glycosaminoglycan. ### Claim 20 (depends on 19) The composition of claim 19, wherein said glycosaminoglycan is selected from the group consisting of hyaluronic acid, chondroitin sulfate, keratane sulfate and dextran sulfate. ### Claim 21 (depends on 17) The chitosan composition of claim 17, wherein said at least one negatively charged substance comprises a phospholipid. ### Claim 22 (depends on 21) The chitosan composition of claim 21, wherein said phospholipid is phosphatidyl choline. ### Claim 23 (depends on 17) The chitosan composition of claim 17, wherein said at least one negatively charged substance comprises a phospholipid and a glycosaminoglycan. ### Claim 24 (depends on 1) The chitosan composition of claim 1, further comprising at least one of a drug, a polypeptide, and a cell. ### Claim 25 (depends on 1) The chitosan composition of claim 1, wherein the concentration of each of said acetylated chitosan and said deacetylated chitosan ranges from 1% to 1.2% w/v of the composition and said ratio is 1:1. ### Claim 26 (depends on 25) The chitosan composition of claim 25, wherein said highly deacetylated chitosan has a molecular weight of from 400 kDa to 700 kDa and said highly acetylated chitosan has a molecular weight of from 200 kDa to 250 kDa. ### Claim 27 (depends on 1) The chitosan composition of claim 1, wherein said deacetylated chitosan has a molecular weight of at least 2000 kDa and the concentration thereof is 0.5%, and further wherein said acetylated chitosan has a molecular weight of from 200 kDa to 250 kDa and further wherein said ratio of said acetylated chitosan and said deacetylated chitosan ranges from 2:1 to 4:1. ### Claim 28 (depends on 1) The chitosan composition of claim 1, further comprising Ttri-N-acetyl-glucosamine bound to said acetylated chitosan. ### Claim 29 (depends on 1) The chitosan composition of claim 1, further comprising an emulsifier. ### Claim 30 (depends on 29) The chitosan composition of claim 29, wherein said chitosans and said emulsifier form nanoparticles. ### Claim 31 (depends on 30) The chitosan composition of claim 30, wherein said nanoparticles are encapsulated in the hydrogel. ### Claim 32 (depends on 1) The chitosan composition of claim 1, wherein the hydrogel forms upon injecting the composition to a subject. ### Claim 33 (depends on 1) The chitosan composition of claim 1, in the form of an injectable solution. ### Claim 34 A process for preparing a stable pH-dependant and temperature-dependant 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 of from about 70%, the process comprising: a) dissolving said acetylated chitosan and said deacetylated chitosan in an acidic aqueous solution, 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; b) adjusting the pH of said composite solution to a value of from 6.6 to 7; and c) increasing the temperature of said composite solution to about 37° C. while raising the pH to at least 7.0. ### Claim 35 (depends on 34) A hydrogel formed by the process of claim 34. ### Claim 36 (depends on 1) A matrix, system or implantable device for use in an application selected from the group consisting of drug delivery, food additive delivery, support of cell growth, bone structural support, cartilage repair, tissue reconstruction, wound healing, production of artificial skin, treatment of hypolipidemia, treatment of hypocholesterolemia, formation of artificial kidney membrane, bone filling, anti adhesion in the field of surgery, lubrication, synovial replacement and mesotherapy, comprising the chitosan hydrogel composition of claim 1. ### Claim 37 (depends on 36) The matrix, system or device according to claim 36, wherein said application comprises administering said chitosan hydrogel composition by a route selected from the group consisting of direct instillation, injection and endoscopic administration. ### Claim 38 (depends on 1) An implantable device comprising the chitosan hydrogel composition of claim 1. ### Claim 39 (depends on 38) The implantable device according to claim 38, being used for an application selected from the group consisting of tissue repair, tissue reconstruction, tissue construction, and tissue replacement. ### Claim 40 (depends on 1) A drug delivery system comprising the chitosan hydrogel composition of claim 1 and a drug embedded therein. ### Claim 41 (depends on 40) The drug delivery system of claim 40, wherein said drug is selected from the group consisting of an ACE-inhibitor and an anti inflammatory drug. ### Claim 42 (depends on 1) A three-dimensional gel construct comprising the chitosan hydrogel composition of claim 1 and cells embedded therein, said cells being invading endogenous cells or exogenous cells for providing a metabolite. ### Claim 43 (depends on 1) A cell-loaded artificial matrix comprising the chitosan hydrogel composition of claim 1 and cell embedded therein. ### Claim 44 (depends on 1) A biofilm disruptor comprising the chitosan hydrogel composition of claim 1. ### Claim 45 (depends on 1) A lubricant comprising the chitosan hydrogel composition of claim 1. ### Claim 46 (depends on 1) A synovial replacement composition comprising the chitosan composition of claim 1. ### Claim 47 (depends on 17) A synovial replacement composition comprising the chitosan composition of claim 17. ### Claim 48 A chitosan composition which forms a hydrogel at near physiological pH and at 37° C., the composition comprising at least one deacetylated chitosan having a molecular weight of from 10-4000 kDa and a degree of deacetylation of at least 70%, and at least one chitosan oligomer having a molecular weight of from 200-20000 Da; wherein the ratio of said chitosan oligomer to said deacetylated chitosan ranges from 2:1 to 20:1, the composition being in a form of an aqueous solution at neutral pH. ### Claim 49 (depends on 48) The chitosan composition of claim 48, wherein said chitosan having a molecular weight of from 200-20000 Da is selected from the group consisting of a highly deacetylated chitosan having a degree of deacetylation of at least 70% and a highly acetylated chitosan having a degree of acetylation of from 30% to 60%. ### Claim 50 (depends on 48) The chitosan composition of claim 48, wherein said ratio is higher than 2:1 and less than or equal to 20:1. ### Claim 51 (depends on 48) The chitosan composition of claim 48, wherein said ratio is selected from the group consisting of 2:1; 4:1 and 10:1.