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., 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.

1 .- 26 . (canceled) 
     
     
         27 . 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 composition wherein said highly acetylated chitosan and said highly deacetylated chitosan each independently has a molecular weight in the range of from 100 kDa to 2000 kDa. 
     
     
         28 . The chitosan composition of  claim 27 , wherein said highly acetylated chitosan is either homogenously acetylated or homogenously deacetylated. 
     
     
         29 . The chitosan composition of  claim 27 , wherein said highly deacetylated chitosan is non-homogenously deacetylated. 
     
     
         30 . The chitosan composition of  claim 27 , wherein the highly deacetylated chitosan is a non-homogenously deacetylated chitosan and the highly acetylated chitosan is a homogenously reacetylated chitosan. 
     
     
         31 . The chitosan composition of  claim 27 , 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. 
     
     
         32 . The chitosan composition of  claim 27 , 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. 
     
     
         33 . The chitosan composition of  claim 27 , 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. 
     
     
         34 . The chitosan composition of  claim 27 , wherein a ratio of said highly acetylated chitosan and said highly deacetylated chitosan ranges from 1:2 to 4:1. 
     
     
         35 . The chitosan composition of  claim 34 , wherein said ratio is 1:1. 
     
     
         36 . The chitosan composition of  claim 35 , 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. 
     
     
         37 . The chitosan composition of  claim 27 , wherein said highly deacetylated chitosan has a molecular weight greater than 200 kDa. 
     
     
         38 . The chitosan composition of  claim 27 , wherein said highly deacetylated chitosan has a molecular weight greater than 400 kDa. 
     
     
         39 . The chitosan composition of  claim 27 , wherein said highly acetylated chitosan has a molecular weight of greater than 200 kDa. 
     
     
         40 . The chitosan composition of  claim 27 , 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. 
     
     
         41 . The chitosan composition of  claim 40 , 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. 
     
     
         42 . The chitosan composition of  claim 27 , further comprising at least one negatively charged substance which forms a hybrid with said hydrogel. 
     
     
         43 . The chitosan composition of  claim 42 , wherein said at least one negatively charged substance comprises a negatively charged polysaccharide. 
     
     
         44 . The chitosan composition of  claim 43 , wherein said negatively charged polysaccharide is a glycosaminoglycan. 
     
     
         45 . The chitosan composition of  claim 44 , wherein said glycosaminoglycan is selected from the group consisting of hyaluronic acid, chondroitin sulfate, keratan sulfate and dextran sulfate. 
     
     
         46 . The chitosan composition of  claim 27 , further comprising at least one of a drug, a polypeptide, and a cell.