Surgical hydrogel

Abstract

The invention provides a hydrogel suitable for use in wound healing, particularly for reducing post-surgical adhesions. The hydrogel comprises cross-linked derivatives of chitosan and dextran polymers. The hydrogel forms when solutions of the polymers are combined.

1 . A composition comprising a dicarboxy-derivatised chitosan polymer cross-linked to an aldehyde-derivatized dextran polymer. 
     
     
         2 . The composition as claimed in  claim 1  wherein the dicarboxy-derivatised chitosan polymer is cross-linked to the aldehyde-derivatised dextran polymer through the amine group of the dicarboxy-derivatised chitosan polymer and the aldehyde group of the aldehyde-derivatised dextran polymer. 
     
     
         3 . The composition as claimed in  claim 1  or  claim 2  wherein the polymer network forms a hydrogel within about 1 sec to about 5 minutes of mixing the dicarboxy-derivatised chitosan polymer and the aldehyde-derivatised dextran polymer in aqueous solution. 
     
     
         4 . The composition as claimed in  claim 3  wherein the polymer network forms a hydrogel within about 1 sec to about 30 sec of mixing the dicarboxy-derivatised chitosan polymer and the aldehyde-derivatised dextran polymer in aqueous solution. 
     
     
         5 . The composition as claimed in  claim 1  wherein the dicarboxy-derivatised chitosan polymer is N-succinyl chitosan. 
     
     
         6 . The composition of  claim 1 , further comprising an aqueous solution. 
     
     
         7 . The composition of  claim 6  wherein the composition comprises between about 2% to 10% w/v dicarboxy-derivatised chitosan polymer and between about 2% to 10% w/v aldehyde-derivatised dextran polymer. 
     
     
         8 - 10 . (canceled) 
     
     
         11 . The composition of  claim 7  comprising between about 2% to about 8% w/v dicarboxy-derivatised chitosan polymer and about 2% to about 8% w/v aldehyde-derivatised dextran polymer. 
     
     
         12 . The composition of  claim 7  comprising about 5% w/v dicarboxy-derivatised chitosan polymer and about 5% w/v aldehyde-derivatised dextran polymer. 
     
     
         13 . (canceled) 
     
     
         14 . A method of producing composition of a dicarboxy-derivatised chitosan polymer cross-linked to an aldehyde-derivatised dextran polymer, comprising: mixing an aqueous solution of a dicarbosy-derivatised chitosan polymer with an aqueous solution of an aldehyde-derivatised aldehyde dextran polymer. 
     
     
         15 . A The method of  claim 14  wherein the aqueous solution of a dicarboxy-derivatised chitosan polymer is between about 2% to about 10% w/v and the aqueous solution of dicarboxy-derivatised dextran polymer is between about 2% to about 10% w/v. 
     
     
         16 - 17 . (canceled) 
     
     
         18 . The method of  claim 14  wherein the pH of each aqueous solution is between about 6 to about 8. 
     
     
         19 . (canceled) 
     
     
         20 . The method of  claim 14  wherein the dicarboxy-derivatised chitosan polymer is N-succinyl chitosan. 
     
     
         21 . The composition of  claim 1 , further comprising one or more biologically active agents. 
     
     
         22 . The composition of  claim 21  wherein said one or more biologically active agents are selected from the group consisting of plasma proteins, hormones, enzymes, antibiotics, antiseptic agents, antineoplastic agents, antifungal agents, antiviral agents, anti-inflammatory agents, growth factors, steroids, cell suspensions, cytotoxins, and cell proliferation inhibitors. 
     
     
         23 . A method of preventing or reducing adhesion of tissue susceptible to adhesion formation comprising treating the tissue with a composition of  claim 1 . 
     
     
         24 . The method of  claim 23  wherein the adhesion is a post-surgical adhesion. 
     
     
         25 . A method of accelerating or promoting wound healing comprising treating the wound with a composition of  claim 1 . 
     
     
         26 . A method of reducing or stopping bleeding of a wound comprising treating the wound with a composition of  claim 1 . 
     
     
         27 - 28 . (canceled) 
     
     
         29 . A method of treating a tissue comprising applying to said tissue:
 (a) an aqueous solution of a dicarboxy-derivatised chitosan polymer; and   (b) an aqueous solution of an aldehyde-derivatised dextran polymer, such that (a) and (b) combine to form a cross-linked composition on said tissue.   
     
     
         30 . The method of  claim 29 , wherein said tissue has been injured. 
     
     
         31 . The method of  claim 30 , wherein said injury is selected from the group consisting of wound, surgery or results in bleeding. 
     
     
         32 . The method of  claim 29 , wherein said step of applying is selected from the group consisting of spraying, squirting or pouring. 
     
     
         33 . The method of  claim 29  wherein (a) and (b) are simultaneously applied to said tissue. 
     
     
         34 . (canceled) 
     
     
         35 . The method of  claim 29  wherein cross-linked composition forms within about 1 sec to about 5 minutes of combining (a) and (b). 
     
     
         36 . (canceled) 
     
     
         37 . The method of  claim 29  wherein the dicarboxy-derivatised chitosan polymer is N-succinyl chitosan. 
     
     
         38 . A wound dressing comprising the composition of  claim 1 . 
     
     
         39 . A kit comprising:
 (a) dicarboxy-derivatised chitosan polymer, and   (b) an aldehyde-derivatized dextran polymer.   
     
     
         40 . The kit as claimed in  claim 39  wherein (a) and (b) are freeze-dried. 
     
     
         41 . The kit as claimed in  claim 39  wherein either or both of (a) and (b) are provided in separate aqueous solutions. 
     
     
         42 . The kit of  claim 41  wherein the aqueous solution of (a) is between about 2% to about 10% w/v and the aqueous solution of (b) is between about 2% to about 10% w/v. 
     
     
         43 . A The kit of  claim 42  wherein the aqueous solutions comprise between about 0.1% to about 2% w/v NaCl. 
     
     
         44 . The kit of  claim 39  additionally comprising an aqueous solution in which (a) and (b) can be dissolved to allow cross-linking to occur. 
     
     
         45 . The kit of  claim 39  wherein (a) is N-succinyl chitosan.