Photostable Wound Dressing Materials and Methods of Production Thereof

• US 20080305138A1
• Filed: 03/16/2006
• Published: 12/11/2008
• Est. Priority Date: 04/26/2005
• Status: Abandoned Application

• Current Assignee: Systagenix Wound Management Ip Co., B.V (3M Company)
• Original Assignee: Systagenix Wound Management Ip Co., B.V (3M Company)
• Inventors: Cullen, Breda Mary, Silcock, Derek W., Boyle, James
• Application Number:
  US11/912,326
• Publication Number:
  US 20080305138A1
• Time in Patent Office: Days
• US Class Current: 424/411
• CPC Class Codes: A61L 15/225 Mixtures of macromolecular compounds
• CPC Class Codes: A61L 15/28 Polysaccharides or their derivatives A61L15/225 takes precedence
• CPC Class Codes: A61L 15/425 Porous materials, e.g. foams or sponges
• CPC Class Codes: A61L 15/46 Deodorants or malodour counteractants, e.g. to inhibit the formation of ammonia or bacteria
• CPC Class Codes: A61L 2300/104 Silver, e.g. silver sulfadiazine
• CPC Class Codes: A61L 2300/404 Biocides, antimicrobial agents, antiseptic agents
• CPC Class Codes: C08L 1/04 Oxycellulose; Hydrocellulose , e.g. microcrystalline cellulose

Abstract

The invention provides a method of preparing an antimicrobial sponge material for medicinal use, comprising the steps of: treating an anionic polysaccharide with a solution of a silver salt to produce a complex of the anionic polysaccharide with silver; dispersing said complex in aqueous ascorbic acid to form an acidified dispersion, followed by freeze-drying or solvent-drying the dispersion to form the sponge material. Also provided is a photostabilized antimicrobial sponge material comprising an anionic polysaccharide complexed with silver (I) ions, wherein the sponge further comprises ascorbic acid, and the sponge has a substantially white colour that is substantially stable against discoloration on exposure to light. Also provided are wound dressings comprising such materials, and the use of such materials in medicine.

Claims

1. A method of preparing an antimicrobial sponge material for medicinal use, comprising the steps of:

treating an anionic polysaccharide with a solution of a silver salt to produce a complex of the anionic polysaccharide with silver;

dispersing said complex in aqueous ascorbic acid to form an acidified dispersion, followed by freeze-drying or solvent-drying the dispersion to form the sponge material.

2. The method of claim 1 wherein the ionic polysaccharide consists essentially of oxidized regenerated cellulose (ORC).

3. The method of claim 1, wherein the said dispersion further comprises one or more additional medically acceptable polymeric materials dispersed therein.

4. The method of claim 3, wherein the dispersion further comprises a substantially silver-free ORC and a collagen, and the silver concentration in the dispersion is from about 0.1% to about 2% by weight based on total polymeric solids.

5. The method of claim 1 wherein the dispersion has a pH of from about 3 to about 4, and a solids concentration of from about 0.5% to about 2%.

6. A photostabilized antimicrobial sponge material obtained or obtainable by a method according to claim 1.

8. A wound dressing comprising an antimicrobial sponge material according to claim 6.

9. A wound dressing according to claim 8, wherein the wound dressing is sterile and packaged in a microorganism-impermeable container.

7. A photostabilized antimicrobial sponge material comprising an anionic polysaccharide complexed with silver (I) ions, wherein the sponge further comprises ascorbate, and the sponge has a substantially white colour that is substantially stable against visible discoloration on exposure to natural daylight for 24 hours at 25°

C. and in air.

10. Use of ascorbic acid in an antimicrobial material comprising a silver (I) salt of a medically acceptable polyanionic acid to stabilize said material against discoloration on exposure to light.