Wound treatment-dressing and method of manufacture

Abstract

A wound treatment-dressing is shown which includes a dressing body formed from a medically inert, moisture permeable, urethane open-cell foam which is hydrophilic in nature. The foam body has a foam matrix of interconnected foam cells with cell walls which have incorporated therein a combination of inorganic antimicrobials as active agents, the active agents being incorporated into the foam matrix both topically on a foam cell surface and integrally within the foam cell wall. The antimicrobials are manufactured in a selected particle size range which improves predictability and performance of the wound dressing.

1 . A wound treatment-dressing, comprising: 
 a dressing body having at least a wound contacting surface layer which is formed from a medically inert, moisture permeable, urethane open-cell foam;    wherein the foam which makes up at least the wound contacting surface of the dressing body exists as a foam matrix comprised of interconnected foam cells with cell walls which has incorporated therein a combination of inorganic antimicrobials as active agents, the active agents being incorporated into the foam matrix on both topically on a foam cell surface and integrally within the foam cell wall.    
   
   
       2 . The wound treatment-dressing of  claim 1 , wherein the active agents are selected from the group consisting of gram positive antimicrobials, gram negative antimicrobials, iodine, and ionic and colloidal silver.  
   
   
       3 . The wound treatment-dressing of  claim 2 , wherein the foam body also has incorporated therein a zirconium phosphate-based ceramic ion-exchange resin containing silver in the form of silver ions which slowly releases silver ions via an ion exchange mechanism.  
   
   
       4 . The wound treatment-dressing of  claim 2 , wherein the active agents comprises the combination of gentian-violet, methylene-blue and colloidal or ionic silver.  
   
   
       5 . The wound treatment-dressing of  claim 4 , wherein the foam body has a volume absorbency ratio which is greater than about 20:1.  
   
   
       6 . The wound treatment-dressing of  claim 1 , wherein the active agents are at least partially encapsulated within the cell wall surface, which thereby immobilizes the active agent, and thus provides for sterile rinsing and potential re-use where conditions warrant.  
   
   
       7 . The wound treatment-dressing of  claim 2 , wherein the gentian-violet and methylene-blue components are present in the foam matrix as nano-sized particles which range in spherical diameter from about 19 microns to 8000 microns.  
   
   
       8 . The wound treatment-dressing of  claim 7 , wherein a given weight percentage of each antimicrobial agent in the form of particles is physically mixed into the polymer foam ingredients prior to foaming, such that the antimicrobials are mechanically included in the foam cell wall upon foaming, whereby some quantity of antimicrobial particles will be totally encapsulated into the wall's polymer structure with the remaining quantity protruding through the polymer wall boundary to be physically exposed into the void space of the open-foam cell.  
   
   
       9 . The wound treatment-dressing of  claim 8 , wherein the antimicrobial particles are not deposited onto the cell wall, but are physically included within and physically protruding from the cell wall.  
   
   
       10 . A method of manufacturing a wound treatment-dressing, the method comprising the steps of: 
 providing a dressing body having at least a wound contacting surface layer which is formed from a medically inert, moisture permeable, urethane open-cell foam;    wherein the foam which makes up at least the wound contacting surface of the dressing body exists as a foam matrix comprised of interconnected foam cells with cell walls which has incorporated therein a combination of inorganic antimicrobials as active agents, the active agents being incorporated into the foam matrix on both topically on a foam cell surface and integrally within the foam cell wall; and    wherein a given weight percentage of each antimicrobial agent in the form of particles is physically mixed into the polymer foam ingredients prior to foaming, such that the antimicrobials are mechanically included in the foam cell wall upon foaming, whereby some quantity of antimicrobial particles will be totally encapsulated into the wall's polymer structure with the remaining quantity protruding through the polymer wall boundary to be physically exposed into the void space of the open-foam cell.    
   
   
       11 . The method of  claim 10 , wherein the active agents are selected from the group consisting of gram positive antimicrobials, gram negative antimicrobials, iodine, and ionic and colloidal silver.  
   
   
       12 . The method of  claim 11 , wherein the foam body also has incorporated therein a zirconium phosphate-based ceramic ion-exchange resin containing silver in the form of silver ions which slowly releases silver ions via an ion exchange mechanism.  
   
   
       13 . The method of  claim 12 , wherein the active agents comprises the combination of gentian-violet, methylene-blue and colloidal or ionic silver.  
   
   
       14 . The method of  claim 13 , wherein the method further comprises the steps of: 
 manufacturing nano-sized antimicrobial particles for incorporation into the foam matrix by first solvating gentian-violet or methylene-blue into a warm solvent at the thermal saturation limit; thereafter, pressure spraying the concentrated solution through a droplet atomizing nozzle such that tiny uniform droplets of hot concentrated solution are ejected into a vacuum chamber where the solvent flashes, leaving tiny, uniform solid crystal particles at the chamber bottom;    thereafter, evacuating the solvent gas via vacuum pump, and removing the resulting nano-sized antimicrobial particles of generally uniform spherical diameter.    
   
   
       15 . The method of  claim 14 , wherein the gentian-violet and methylene-blue components are present in the foam matrix as nano-sized particles which range in spherical diameter from about 19 microns to 8000 microns.