Novel injectable chitosan mixtures forming hydrogels

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.

1 . A chitosan composition which forms a hydrogel at near physiological pH and at 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%, the composition being in a form of an aqueous solution. 
     
     
         2 . The chitosan composition of  claim 1 , wherein said highly acetylated chitosan is either homogenously acetylated or homogenously deacetylated. 
     
     
         3 . The chitosan composition of  claim 1 , wherein said highly deacetylated chitosan is non-homogenously deacetylated. 
     
     
         4 . The chitosan composition of  claim 1 , wherein said highly acetylated chitosan and said highly deacetylated chitosan are each independently present at a concentration of from 0.2% to 3% w/v of the total composition. 
     
     
         5 . The chitosan composition of  claim 1 , wherein said highly acetylated chitosan and said highly deacetylated chitosan are each independently present at a concentration of from 0.3% to 2% w/v of the total composition. 
     
     
         6 . The chitosan composition of  claim 1 , wherein said highly acetylated chitosan and said highly deacetylated chitosan are each independently present at a concentration of from 1% to 1.2% w/v of the total composition. 
     
     
         7 . The chitosan composition of  claim 1 , wherein a ratio of said highly acetylated chitosan and said highly deacetylated chitosan ranges from 1:2 to 4:1. 
     
     
         8 . The chitosan composition of  claim 7 , wherein said ratio is 1:1. 
     
     
         9 . The chitosan composition of  claim 8 , wherein said highly acetylated chitosan and said highly deacetylated chitosan are each present at a concentration of from 1% to 1.2% w/v of the total composition. 
     
     
         10 . The chitosan composition of  claim 1 , wherein said highly acetylated chitosan and said highly deacetylated chitosan each independently has a molecular weight in the range of from 10 kDa to 4000 kDa. 
     
     
         11 . The chitosan composition of  claim 10 , wherein said highly deacetylated chitosan has a molecular weight greater than 60 kDa. 
     
     
         12 . The chitosan composition of  claim 10 , wherein said highly deacetylated chitosan has a molecular weight greater than 200 kDa. 
     
     
         13 . The chitosan composition of  claim 10 , wherein said highly deacetylated chitosan has a molecular weight greater than 400 kDa. 
     
     
         14 . The chitosan composition of  claim 11 , wherein said highly acetylated chitosan has a molecular weight of greater than 200 kDa. 
     
     
         15 . The chitosan composition of  claim 10 , wherein said highly deacetylated chitosan has a molecular weight that ranges from 400 kDa to 700 kDa and said highly acetylated chitosan has a molecular weight that ranges from 200 kDa to 250 kDa. 
     
     
         16 . The chitosan composition of  claim 15 , wherein said highly acetylated chitosan and said highly deacetylated chitosan are each present at a concentration of from 1% to 1.2% w/v of the total composition. 
     
     
         17 . The chitosan composition of  claim 1 , further comprising at least one negatively charged substance which forms a hybrid with said hydrogel. 
     
     
         18 . The chitosan composition of  claim 17 , wherein said at least one negatively charged substance comprises a negatively charged polysaccharide. 
     
     
         19 . The chitosan composition of  claim 18 , wherein said negatively charged polysaccharide is a glycosaminoglycan. 
     
     
         20 . The composition of  claim 19 , wherein said glycosaminoglycan is selected from the group consisting of hyaluronic acid, chondroitin sulfate, keratane sulfate and dextran sulfate. 
     
     
         21 . The chitosan composition of  claim 17 , wherein said at least one negatively charged substance comprises a phospholipid. 
     
     
         22 . The chitosan composition of  claim 21 , wherein said phospholipid is phosphatidyl choline. 
     
     
         23 . The chitosan composition of  claim 17 , wherein said at least one negatively charged substance comprises a phospholipid and a glycosaminoglycan. 
     
     
         24 . The chitosan composition of  claim 1 , further comprising at least one of a drug, a polypeptide, and a cell. 
     
     
         25 . The chitosan composition of  claim 1 , wherein the properties of said hydrogel are controlled by manipulation of said highly acetylated chitosan and said highly deacetylated chitosan. 
     
     
         26 . The chitosan composition of  claim 25 , wherein said properties of said hydrogel controlled by said manipulation are selected from the group consisting of gelation temperature, gelation pH, density and porosity. 
     
     
         27 . The chitosan composition of  claim 26 , wherein said manipulation comprises manipulation of a feature selected from the group consisting of degree of hydration and degree of hydrophobicity. 
     
     
         28 . The chitosan composition of  claim 26 , wherein said manipulation comprises manipulation of a feature selected from the group consisting of a molecular weight of each of said highly acetylated chitosan and said highly deacetylated chitosan, a concentration of each of said highly acetylated chitosan and said highly deacetylated chitosan in the composition and a ratio of said highly acetylated chitosan and said highly deacetylated chitosan. 
     
     
         29 . The chitosan composition of  claim 28 , wherein when a concentration of each of said highly acetylated chitosan and said highly deacetylated chitosan ranges from 1% to 1.2% w/v of the composition and said ratio is 1:1, the hydrogel is formed at said near physiological pH. 
     
     
         30 . The chitosan composition of  claim 29 , 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. 
     
     
         31 . The chitosan composition of  claim 28 , wherein when said highly deacetylated chitosan has a molecular weight of at least 2000 kDa and a concentration thereof is 0.5%, and further when said highly acetylated chitosan has a molecular weight of from 200 kDa to 250 kDa and said ratio ranges from 2:1 to 4:1, the hydrogel is formed at said near physiological pH. 
     
     
         32 . The chitosan composition of  claim 1 , wherein a degradation rate of the hydrogel is controlled by binding of the lysozyme inhibitor Tri-N-acetyl-glucosamine to said highly acetylated chitosan. 
     
     
         33 . The chitosan composition of  claim 1 , further comprising an emulsifier. 
     
     
         34 . The chitosan composition of  claim 33 , wherein said chitosans and said emulsifier form nanoparticles. 
     
     
         35 . The chitosan composition of  claim 34 , wherein said nanoparticles are encapsulated in the hydrogel. 
     
     
         36 . The chitosan composition of  claim 1 , wherein the hydrogel forms upon injecting the composition to a subject. 
     
     
         37 . The chitosan composition of  claim 1 , being an injectable composition. 
     
     
         38 . A process for preparing a stable pH-dependant and temperature-dependant chitosan hydrogel composition comprised of at least one highly acetylated chitosan having a degree of acetylation of from about 30 to about 60%, and at least one highly deacetylated chitosan having a degree of deacetylation of from about 70%, the process comprising:
 a) dissolving said highly acetylated chitosan and said highly deacetylated chitosan in an acidic aqueous solution, to thereby form a composite solution;   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.   
     
     
         39 . A hydrogel formed by the process of  claim 38 . 
     
     
         40 . 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 . 
     
     
         41 . The matrix, system or device according to  claim 40 , wherein said application comprises administering said chitosan hydrogel composition by a route selected from the group consisting of direct instillation, injection and endoscopic administration. 
     
     
         42 . An implantable device comprising the chitosan hydrogel composition of  claim 1 . 
     
     
         43 . The implantable device according to  claim 42 , being used for an application selected from the group consisting of tissue repair, tissue reconstruction, tissue construction, and tissue replacement. 
     
     
         44 . A drug delivery system comprising the chitosan hydrogel composition of  claim 1  and a drug embedded therein. 
     
     
         45 . The drug delivery system of  claim 44 , wherein said drug is selected from the group consisting of an ACE-inhibitor and an anti inflammatory drug. 
     
     
         46 . 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. 
     
     
         47 . A cell-loaded artificial matrix comprising the chitosan hydrogel composition of  claim 1  and cell embedded therein. 
     
     
         48 . A biofilm disruptor comprising the chitosan hydrogel composition of  claim 1 . 
     
     
         49 . A lubricant comprising the chitosan hydrogel composition of  claim 1 . 
     
     
         50 . A synovial replacement composition comprising the chitosan composition of  claim 1 . 
     
     
         51 . A synovial replacement composition comprising the chitosan composition of  claim 17 . 
     
     
         52 . A synovial replacement composition comprising the chitosan composition of  claim 23 . 
     
     
         53 . A chitosan composition which forms a hydrogel at near physiological pH and at 37° C., the composition comprising at least one type of a highly deacetylated chitosan having a molecular weight of from 10-4000 kDa and a degree of deacetylation of at least 70%, and at least one type of a chitosan having a molecular weight of from 200-20000 Da, the composition being in a form of an aqueous solution. 
     
     
         54 . The chitosan composition of  claim 53 , 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%. 
     
     
         55 . The chitosan composition of  claim 53 , wherein a ratio of said chitosan having a molecular weight of from 200-20000 Da and said highly deacetylated chitosan having a molecular weight of from 10-4000 kDa and a degree of deacetylation of at least 70% is higher than 1:1. 
     
     
         56 . The chitosan composition of  claim 55 , wherein said ratio ranges from 2:1 to 20:1.