Injectable monophase hydrogels

Abstract

An injectable monophase hydrogel is provided and is made of a reaction mixture of a high molecular weight hyaluronic acid and a low molecular weight hyaluronic acid.

What is claimed is : 
     
         1 . An injectable product useful as a filling material in plastic or cosmetic surgery, the hydrogel comprising:
 a homogenous, monophase injectable hydrogel comprising crosslinked hyaluronic acid and made from a reaction mixture comprising a low molecular weight hyaluronic acid and a high molecular weight hyaluronic acid.   
     
     
         2 . The product of  claim 1  wherein the low molecular weight hyaluronic acid has a molecular weight m of ≦9.9×10 5  Da. 
     
     
         3 . The product of  claim 1  wherein the low molecular weight hyaluronic acid has a molecular weight m of 10 4  Da≦m 9.9×10 5  Da. 
     
     
         4 . The product of  claim 1  wherein the high molecular weight hyaluronic acid has a molecular weight M of ≧10 6  Da. 
     
     
         5 . The product of  claim 1  wherein the high molecular weight hyaluronic acid has a molecular weight M of 10 6  Da≦M≦10 8  Da. 
     
     
         6 . The product of  claim 1  wherein the high molecular weight hyaluronic acid has a molecular weight M of 1.1×10 6  Da≦M≦5×10 6  Da. 
     
     
         7 . The product of  claim 1  wherein the reaction mixture has an intrinsic viscosity of less than 1900 ml/g. 
     
     
         8 . The product of  claim 1  wherein the reaction mixture contains more than 50% by weight of the low molecular weight hyaluronic acid. 
     
     
         9 . The product of  claim 1  wherein the reaction mixture contains more than 70% by weight of the low molecular weight hyaluronic acid. 
     
     
         10 . The product of  claim 1  wherein the reaction mixture contains 90% by weight of the low molecular weight hyaluronic acid. 
     
     
         11 . The product of  claim 1  wherein the reaction mixture contains at least 5% by weight of the high molecular weight hyaluronic acid. 
     
     
         12 . The product of  claim 1  that is manually injectable through a hypodermic needle having a needle gauge selected from one of 30 G, 27 G, 26 G and 25 G. 
     
     
         13 . The product of  claim 1  that is injectable through a hypodermic needle of 27 G. 
     
     
         14 . The product of  claim 1  having a hyaluronic acid concentration between 10 mg/g and 40 mg/g. 
     
     
         15 . The product of  claim 1  having a hyaluronic acid concentration between 20 mg/g and 30 mg/g. 
     
     
         16 . An injectable composition useful as a filling material in plastic or cosmetic surgery, the composition comprising:
 a homogenous, monophase injectable hydrogel comprising a crosslinked hyaluronic acid;   the hydrogel made using a mixture containing at least 50% of a low molecular weight hyaluronic acid salt and a sufficient amount of a high molecular weight hyaluronic acid salt to obtain a coherent crosslinked compostion that is the precursor of the monophase injectable hydrogel.   
     
     
         17 . The composition of  claim 16  wherein the hydrogel has a hyaluronic acid concentration between 10 mg/g and 40 mg/g. 
     
     
         18 . The composition of  claim 17  wherein the mixture contains at least 5% by weight of the high molecular weight hyaluronic acid salt. 
     
     
         19 . The composition of  claim 17  that is manually injectable through a hypodermic needle having a needle gauge selected from one of 30 G, 27 G, 26 G and 25 G. 
     
     
         20 . The composition of  claim 17  that is injectable through a hypodermic needle of 27 G.