Silver containing wound dressing

Abstract

A wound dressing having anti-microbial activity comprises a first fibre capable of bonding with silver ( 1 ) cations. The wound dressing comprises a blend of the first fibre to which silver ( 1 ) cations are bonded and a second fibre which is substantially free from silver. The wound dressing comprises from 0.01 to 5.0 percent by weight of silver ( 1 ) cations, based on the weight of fibre.

1 . A wound dressing having anti-microbial activity, which wound dressing comprises a first fibre capable of bonding with silver ( 1 ) cations, characterised in that the wound dressing comprises a blend of the first fibre to which silver ( 1 ) cations are bonded and a second fibre which is substantially free from silver.  
     
     
         2 . A wound dressing according to  claim 1  characterised in that it comprises from 0.01 to 5.0 percent by weight, of silver ( 1 ) cations based on the weight of fibre.  
     
     
         3 . A wound dressing according to  claim 2  characterised in that it comprises from 0.1 to 4.0 percent by weight of silver ( 1 ) cations based on the weight of fibre.  
     
     
         4 . A wound dressing according to  claim 3  characterised in that it comprises from 0.25 to 3.0 percent by weight of silver ( 1 ) cations based on the weight of fibre.  
     
     
         5 . A wound dressing according to any of  claims 1  to  4  characterised in that the first fibre is substantially insoluble in water.  
     
     
         6 . A wound dressing according to any of  claims 1  to  5  characterised in that the first fibre comprises a carboxymethylcellulose fibre, an alginate fibre, a chitosan or chitosan derivative fibre or an acrylic fibre.  
     
     
         7 . A wound dressing according to  claim 6  characterised in that the first fibre is a carboxymethyl cellulose fibre and the wound dressing contains from 1.0 to 2.0% by weight of silver ( 1 ) cations, based on the weight of the fibre.  
     
     
         8 . A wound dressing according to  claim 6  characterised in that the first fibre is an alginate fibre and the wound dressing contains from 0.25 to 0.75% by weight of silver ( 1 ) cations, based on the weight of the fibre.  
     
     
         9 . A wound dressing according to  claim 6  or  claim 7  characterised in that the first fibre is a carboxymethylcellulose fibre which has a degree of substitution between 0.1 and 0.4.  
     
     
         10 . A wound dressing according to  claim 6  characterised in that the first fibre is an acrylic fibre which incorporates a comonomer to provide dye-sites in the fibre.  
     
     
         11 . A wound dressing according to  claim 10  characterised in that the comonomer isitaconic acid or 2-acrylomido methyl propane sulphonic acid.  
     
     
         12 . A wound dressing according to any of  claims 1  to  11  characterised in that the first fibre and the second fibre are similar.  
     
     
         13 . A wound dressing according to any of  claims 1  to  12  characterised in that the ratio of the first fibre to the second fibre is in the range of from 0.5 to 25% by weight of the total weight of the fibre.  
     
     
         14 . A wound dressing according to  claim 13  characterised in that the ratio of the first fibre to the second fibre is in the range of from 5 to 20% by weight of the total weight of the fibre.  
     
     
         15 . A wound dressing according to any of  claims 1  to  10  characterised in that the first fibre includes about 10% by weight, based on the weight of fibre, of silver ( 1 ) cations.  
     
     
         16 . A wound dressing according to any of  claims 1  to  12  characterised in that the silver ions are preferably chemically bonded to the first fibre.  
     
     
         17 . A wound dressing according to any of  claims 9  to  14  characterised in that the first fibre is a carboxymethylcellulose fibre and the degree of substitution is in the range from 0.20 to 0.35.  
     
     
         18 . A wound dressing according to  claim 14  characterised in that the degree of substitution is about 0.3.  
     
     
         19 . A wound dressing according to any of  claims 1  to  15  characterised in that the silver ions are introduced into the first fibre by ion-exchange.  
     
     
         20 . A wound dressing according to any of  claims 1  to  16  characterised in that the first fibre is a carboxymethylcellulose fibre and the carboxymethylcellulose is derived from lyocell.  
     
     
         21 . A wound dressing according to any of  claims 1  to  17  characterised in that the fibrous carboxymethylcellulose is in the form of a staple fibre or continuous filament yarn.  
     
     
         22 . A wound dressing according to any one of the preceding claims characterised in that the carboxymethylcellulose is present in a needlepunched nonwoven textile.  
     
     
         23 . A wound dressing substantially as herein described and with reference to the Example 5.