Polymer Hydrogels and Methods of Preparation Thereof

Abstract

The invention relates to a method for the preparation of a polymer hydrogel, comprising cross-linking a precursor comprising a hydrophilic polymer optionally in combination with a second hydrophilic polymer, using a polycarboxylic acid as the cross-linking agent. The invention further concerns the polymer hydrogel obtainable by the method of the invention and the use thereof in a number of different applications.

1 - 35 . (canceled) 
     
     
         36 . A polymer hydrogel comprising an ionic polymer and a polycarboxylic acid selected from C 4 -C 12 -dicarboxylic acids, tricarboxylic acids and tetracarboxylic acids, wherein said polycarboxylic acid cross-links the ionic polymer, said polymer hydrogel having a swelling ratio in distilled water of at least about 50. 
     
     
         37 . The polymer hydrogel of  claim 36 , wherein the ionic polymer is carboxymethylcellulose and the polycarboxylic acid is citric acid. 
     
     
         38 . The polymer hydrogel of  claim 37  wherein the weight ratio of citric acid to carboxymethylcellulose is about 1% to about 5%. 
     
     
         39 . (canceled) 
     
     
         40 . The polymer hydrogel of  claim 36  having a swelling ratio in distilled water of at least 70. 
     
     
         41 . The polymer hydrogel of  claim 40  having a swelling ratio in distilled water of at least about 100. 
     
     
         42 - 51 . (canceled) 
     
     
         52 . The polymer hydrogel of  claim 40  having a swelling ratio in distilled water of at least 80. 
     
     
         53 . The polymer hydrogel of  claim 40  having a swelling ratio in distilled water of about 50 to about 250. 
     
     
         54 . The polymer hydrogel of  claim 40  having a swelling ratio in distilled water of about 50 to about 350. 
     
     
         55 . A pharmaceutical composition comprising the polymer hydrogel of  claim 36 . 
     
     
         56 . The pharmaceutical composition of  claim 55  wherein the ionic polymer is carboxymethylcellulose and the polycarboxylic acid is citric acid. 
     
     
         57 . The pharmaceutical composition of  claim 56  wherein the weight ratio of citric acid to carboxymethylcellulose is about 1% to about 5%. 
     
     
         58 . The pharmaceutical composition of  claim 55  wherein the polymer hydrogel has a swelling ratio in distilled water of at least about 70. 
     
     
         59 . The pharmaceutical composition of  claim 55  wherein polymer hydrogel has a swelling ratio in distilled water of at least about 100. 
     
     
         60 . The pharmaceutical composition of  claim 55  wherein the polymer hydrogel has a swelling ratio in distilled water of at least about 80. 
     
     
         61 . The pharmaceutical composition of  claim 55  wherein the polymer hydrogel has a swelling ratio in distilled water of about 50 to about 250. 
     
     
         62 . The pharmaceutical composition of  claim 55  wherein the polymer hydrogel has a swelling ratio in distilled water of about 50 to about 350.