Use of a Polyurethane Foam as a Wound Dressing in Negative Pressure Therapy

Abstract

A device for negative pressure wound therapy having a cover material for air-tight sealing of the wound space connected to a negative pressure source; and a wound dressing having an open-cell polyurethane foam. The open-cell polyurethane foam has special properties, in particular a tensile strength after three days of storage in bovine serum, measured in accordance with DIN 53571, between 80 kPa and 300 kPa. The open-cell polyurethane foam may be used as a wound dressing in negative pressure wound therapy.

1 . A device for negative pressure wound therapy comprising
 (a) a cover material for air-tight sealing of the wound space;   (b) optionally, a connector of a negative pressure source; and   (c) an open-cell polyurethane foam as a wound dressing, obtained by reaction of a mixture comprising the components   (i) polyisocyanate selected from the group consisting of diphenylmethane diisocyanate (MDI), mixtures of monomeric diphenylmethane diisocyanates and higher-nucleus homologues of diphenylmethane diisocyanate (polymeric MDI), tetramethylene diisocyanate (TMDI), hexamethylene diisocyanate (HDI), toluylene diisocyanate (TDI) and mixtures thereof,   (ii) polyol,   (iii) blowing agent, and   (iv) catalyst,   wherein the open-cell polyurethane foam has an air permeability of 1,000 to 8,000 l/(m 2 sec), measured in accordance with DIN EN ISO 9237.   
     
     
         2 . The device in accordance with  claim 1 , wherein the polyol is a polyester polyol. 
     
     
         3 . The device in accordance with  claim 1 , whereby the (i) polyisocyanate is selected from the group consisting of MDI, PMDI and TDI. 
     
     
         4 . The device in accordance with  claim 2 , whereby the (ii) polyester polyol is obtainable by reaction of a dicarboxylic acid with 4 to 8 carbon atoms with a dialcohol with 2 to 6 carbon atoms. 
     
     
         5 . The device in accordance with  claim 2 , whereby the (ii) polyester polyol has a weight average molecular weight of 500 to 4,000 g/mol. 
     
     
         6 . The device in accordance with  claim 1 , whereby the open-cell polyurethane foam has a ductile yield of 250% to 650%, measured in accordance with DIN 53571. 
     
     
         7 . (canceled) 
     
     
         8 . The device in accordance with  claim 1 , whereby the open-cell polyurethane foam has a raw density between 15 and 30 kg/m 3 , measured in accordance with DIN EN ISO 845. 
     
     
         9 . The device in accordance with  claim 1 , whereby the open-cell polyurethane foam has a proportion of aromatic compounds of 5 to 50%. 
     
     
         10 . The device in accordance with  claim 1 , whereby the open-cell polyurethane foam has a hardness of 20 to 70 Shore A, measured in accordance with DIN 53505. 
     
     
         11 . The device in accordance with  claim 1 , whereby the open-cell polyurethane foam has a cell number of 5 to 25 cm −1 . 
     
     
         12 . The device in accordance with  claim 1 , whereby the open-cell polyurethane foam displays visco-elastic behavior. 
     
     
         13 . The device in accordance with  claim 1 , whereby the cover material (a) has a water vapor permeability of 100 to 2,500 g/m 2×24 h, measured in accordance with DIN EN 13726-2. 
     
     
         14 . Use of an open-cell polyurethane foam as a wound dressing for negative pressure wound therapy, whereby the open-cell polyurethane foam is obtainable by reaction of a mixture comprising the components
 (i) polyisocyanate selected from diphenylmethane diisocyanate (MDI), in particular, 4,4′-diphenylmethane diisocyanate (4,4′-MDI), mixtures of monomeric diphenylmethane diisocyanates and higher-nucleus homologues of diphenylmethane diisocyanate (polymeric MDI), tetramethylene diisocyanate (TMDI), hexamethylene diisocyanate (HDI), toluylene diisocyanate (TDI) or mixtures thereof can be used to produce the polyurethanes,   (ii) polyol, in particular polyester polyol,   (iii) blowing agent, and   (iv) catalyst,   and   wherein the open-cell polyurethane foam has an air permeability of 1,000 to 8,000 l/(m 2 sec), measured in accordance with DIN EN ISO 9237.   
     
     
         15 . Use in accordance with  claim 14 , whereby the wounds are burn wounds, wounds caused by mechanical trauma, wounds caused by exposure to chemicals, wounds caused by a metabolic disorder, wounds caused by a circulatory disorder, wounds caused by radiation induced ulcer, wounds caused by diabetic foot ulcer, or wounds caused by pressure ulcers. 
     
     
         16 . A method for negative pressure wound therapy, said method comprising dressing a wound with an open-cell polyurethane foam obtained by reaction of a mixture comprising the components
 (i) polyisocyanate selected from the group consisting of diphenylmethane diisocyanate (MDI), mixtures of monomeric diphenylmethane diisocyanates and higher-nucleus homologues of diphenylmethane diisocyanate (polymeric MDI), tetramethylene diisocyanate (TMDI), hexamethylene diisocyanate (HDI), toluylene diisocyanate (TDI) and mixtures thereof, which is used to produce the polyurethane,   (ii) polyester polyol,   (iii) blowing agent, and   (iv) catalyst,   wherein the open-cell polyurethane foam has an air permeability of 1,000 to 8,000 l/(m 2 sec), measured in accordance with DIN EN ISO 9237.   
     
     
         17 . The method of  claim 16 , wherein the polyisocyanate is 4,4′-diphenylmethane diisocyanate (4,4′-MDI). 
     
     
         18 . The method of  claim 16 , wherein the wound is a burn wound, a wound caused by mechanical trauma, a wound caused by exposure to chemicals, a wound caused by a metabolic disorder, a wound caused by a circulatory disorder, a wound caused by radiation induced ulcer, a wound caused by diabetic foot ulcer, or a wound caused by pressure ulcer.