Dissolution of Oxidized Cellulose and Particle Preparation by Solvent and Non-Solvent Precipitation

Abstract

A process for dissolving modified cellulose includes contacting modified cellulose solution with at least one non-solvent to form a plurality of modified cellulose particles.

1 - 24 . (canceled) 
     
     
         25 . A process for forming a gel comprising:
 forming an oxidized cellulose solution;   forming a precipitating composition; and   contacting the oxidized cellulose solution and the precipitating composition at a treatment site thereby precipitating oxidized cellulose from the oxidized cellulose solution and forming the gel.   
     
     
         26 . The process according to  claim 25 , wherein the formation of the oxidized cellulose solution comprises:
 contacting an oxidized cellulose with a solvent under an inert atmosphere to form a swelled oxidized cellulose;   adjusting the swelled oxidized cellulose mixture to a first temperature;   contacting the swelled oxidized cellulose with a salt under the inert atmosphere to form the oxidized cellulose solution; and   adjusting the oxidized cellulose solution to a second temperature that is lower than the first temperature.   
     
     
         27 . The process according to  claim 26 , wherein the first temperature is from about 115° C. to about 145° C. and the second temperature is from about 90° C. to about 120° C. 
     
     
         28 . The process according to  claim 25 , wherein the precipitating composition is selected from the group consisting of water, saline, phosphate buffered saline, and combinations thereof. 
     
     
         29 . The process according to  claim 25 , wherein the precipitating composition is an aqueous solution of carboxymethylcellulose and the carboxymethylcellulose is present from about 0.5% by weight of the solution to about 5% by weight of the solution. 
     
     
         30 . The process according to  claim 25 , wherein the precipitating composition is a solution of an acrylic polymer including at least one of methyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, glyceryl acrylate, glyceryl methacrylate, acrylic acid, methacrylic acid, acrylamide, or methacrylamide, and combinations thereof. 
     
     
         31 . The process according to  claim 30 , wherein the precipitation composition solution comprises a solvent selected from the group consisting of acetone, ethyl acetate, dimethyl ether, and combinations thereof. 
     
     
         32 . The process according to  claim 25 , further comprising convergently applying the oxidized cellulose solution and the precipitating composition onto a treatment site. 
     
     
         33 . A process for forming a cross-linked gel comprising:
 forming an oxidized cellulose solution;   forming a cross-linkable composition covalently cross-linkable with the oxidized cellulose solution; and   contacting the oxidized cellulose solution and the cross-linkable composition at a treatment site thereby forming the cross-linked gel.   
     
     
         34 . The process according to  claim 33 , wherein the cross-linkable composition comprises a Schiff-base compound selected from the group consisting of amoxicillin, cephalexin, and combinations thereof. 
     
     
         35 . The process according to  claim 33 , wherein the cross-linkable composition comprises trilysine, albumin, polyethylene glycol amine, and combinations thereof. 
     
     
         36 . The process according to  claim 35 , wherein the cross-linkable composition is an aqueous solution. 
     
     
         37 . The process according to  claim 34 , further comprising convergently applying the oxidized cellulose solution and the cross-linkable composition onto a treatment site. 
     
     
         38 . A process for forming a gel comprising:
 forming an oxidized cellulose solution;   forming a gelation composition; and   contacting the oxidized cellulose solution and the gelation composition at a treatment site thereby forming the gel.   
     
     
         39 . The process according to  claim 38 , wherein the formation of the oxidized cellulose solution comprises:
 contacting an oxidized cellulose with a solvent under an inert atmosphere to form a swelled oxidized cellulose;   adjusting the swelled oxidized cellulose to a first temperature;   contacting the swelled oxidized cellulose with a salt under the inert atmosphere to form the oxidized cellulose solution; and   adjusting the oxidized cellulose solution to a second temperature that is lower than the first temperature.   
     
     
         40 . The process according to  claim 39 , wherein the first temperature is from about 115° C. to about 145° C. and the second temperature is from about 90° C. to about 120° C. 
     
     
         41 . The process according to  claim 38 , wherein the gelation composition is an aqueous solution of chitosan having a pH from about 2.0 to about 6.0. 
     
     
         42 . The process according to  claim 38 , wherein the oxidized cellulose solution has a pH from about 8.0 to about 9.5. 
     
     
         43 . The process according to  claim 38 , wherein the gelation composition is an aqueous solution of at least one multivalent cation. 
     
     
         44 . The process according to  claim 38 , wherein the at least one multivalent cation is selected from the group consisting of cations of calcium, barium, zinc, magnesium, chromium, platinum, and iron. 
     
     
         45 . The process according to  claim 38 , wherein the gelation composition is selected from the group consisting of water, saline, phosphate buffered saline, and combinations thereof. 
     
     
         46 . The process according to  claim 38 , wherein the gelation composition is an aqueous solution of carboxymethylcellulose and the carboxymethylcellulose is present from about 0.5% by weight of the solution to about 5% by weight of the solution. 
     
     
         47 . The process according to  claim 38 , wherein the gelation composition is a solution of an acrylic polymer based on at least one of methyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, glyceryl acrylate, glyceryl methacrylate, acrylic acid, methacrylic acid, acrylamide, methacrylamide, and combinations thereof. 
     
     
         48 . The process according to  claim 47 , wherein the oxidized cellulose solution comprises a solvent selected from the group consisting of acetone, ethyl acetate, dimethyl ether, and combinations thereof. 
     
     
         49 . The process according to  claim 38 , wherein the gelation composition comprises a Schiff-base compound selected from the group consisting of amoxicillin, cephalexin, and combinations thereof. 
     
     
         50 . The process according to  claim 38 , wherein the gelation composition comprises trilysine, albumin, polyethylene glycol amine, and combinations thereof. 
     
     
         51 . The process according to  claim 38 , further comprising convergently applying the oxidized cellulose solution and the gelation composition onto a treatment site.