Methods for regulating gelation of polysaccharide solutions and uses thereof

Abstract

The present invention provides a method for preparing chitosan solutions to allow regulating the conditions in which the chitosan solution will gel. The present invention also provides methods for using chitosan solutions as compositions and for using chitosan solutions in vitro and in vivo.

1 .- 27 . (canceled) 
     
     
         28 . A method for delivering a material or compound to a subject in need thereof, said method comprising administering to said subject a pharmaceutical composition comprising a thermo-gelling solution consisting of chitosan and an inorganic salt, wherein said inorganic salt is a sulfate salt or a phosphate salt, wherein said thermo-gelling solution is a solution at a pH between about 6.0 and about 8.0 and at a temperature below about 20° C., further wherein said solution forms a gel within a temperature range from about 20° C. to about 50° C., wherein said pharmaceutical composition further comprises said material or compound. 
     
     
         29 . The method of  claim 28 , wherein said material or compound is selected from the group consisting of cells, stem cells, peptides, growth factors, nucleic acids, drugs, matrix components, and imaging agents. 
     
     
         30 . The method of  claim 28 , wherein said administration is by direct administration or by injection. 
     
     
         31 . The method of  claim 28 , wherein said thermo-gelling solution is allowed to gel before said administration. 
     
     
         32 . The method of  claim 31 , where said gel is molded or cut into a plug before said administration. 
     
     
         33 . A method for treating a disease or disorder in a subject in need thereof, said method comprising administering to said subject a pharmaceutical composition comprising a thermo-gelling solution consisting of chitosan and an inorganic salt, wherein said inorganic salt is a sulfate salt or a phosphate salt, wherein said thermo-gelling solution is a solution at a pH between about 6.0 and about 8.0 and at a temperature below about 20° C., further wherein said solution forms a gel within a temperature range from about 20° C. to about 50° C., wherein said pharmaceutical composition optionally comprises an effective amount of at least one material or compound useful for treating said disease or disorder. 
     
     
         34 . The method of  claim 33 , wherein said disease or disorder is a musculoskeletal-associated disease or disorder. 
     
     
         35 . The method of  claim 28 , wherein said inorganic salt is ammonium hydrogen phosphate. 
     
     
         36 . The method of  claim 28 , wherein said thermo-gelling solution is a solution at a pH between about 6.5 and about 7.5. 
     
     
         37 . The method of  claim 28 , wherein said thermo-gelling solution is a solution at a temperature below about 4° C. 
     
     
         38 . The method of  claim 28 , wherein said thermo-gelling solution forms a gel within a temperature range from about 25° C. to about 45° C. 
     
     
         39 . The method of  claim 35 , wherein the concentration of chitosan ranges from about 0.05% to about 10.0% and the concentration of ammonium hydrogen phosphate ranges from about 0.16 M to about 0.06 M. 
     
     
         40 . The method of  claim 28 , wherein said chitosan has a molecular weight of between about 20,000 and 250,000. 
     
     
         41 . The method of  claim 28 , wherein said material or compound is encapsulated in said thermogelling solution once gelling occurs. 
     
     
         42 . The method of  claim 33 , wherein said composition comprises an effective amount of at least one material or compound useful for treating said disease or disorder. 
     
     
         43 . The method of  claim 33 , wherein said material or compound is selected from the group consisting of cells, stem cells, peptides, growth factors, nucleic acids, drugs, matrix components, and imaging agents. 
     
     
         44 . The method of  claim 33 , wherein said administration is by direct administration or by injection. 
     
     
         45 . The method of  claim 33 , wherein said thermo-gelling solution is allowed to gel before said administration. 
     
     
         46 . The method of  claim 45 , where said gel is molded or cut into a plug before said administration. 
     
     
         47 . The method of  claim 33 , wherein said inorganic salt is ammonium hydrogen phosphate. 
     
     
         48 . The method of  claim 33 , wherein said thermo-gelling solution is a solution at a temperature below about 4° C. 
     
     
         49 . The method of  claim 33 , wherein said thermo-gelling solution forms a gel within a temperature range from about 25° C. to about 45° C. 
     
     
         50 . The method of  claim 33 , wherein the concentration of chitosan ranges from about 0.05% to about 10.0% and the concentration of ammonium hydrogen phosphate ranges from about 0.16 M to about 0.06 M. 
     
     
         51 . The method of  claim 33 , wherein said material or compound is encapsulated in said thermogelling solution once gelling occurs.