Dressings

• US 6,191,335 B1
• Filed: 09/13/1999
• Issued: 02/20/2001
• Est. Priority Date: 01/21/1997
• Status: Expired due to Fees

• Current Assignee: Smith & Nephew PLC
• Original Assignee: Smith & Nephew PLC
• Inventors: Robinson, Joseph William
• Primary Examiner(s): Brown, Michael A.
• Assistant Examiner(s): HAMILTON, LALITA M
• Application Number:
  US09/341,880
• Time in Patent Office: 526 Days
• Field of Search: 602/41, 602/43-46, 602/76, 602/77, 128/888, 128/889
• US Class Current: 602/41
• CPC Class Codes: A61F 13/0203 with fluid retention members
• CPC Class Codes: A61L 15/60 Liquid-swellable gel-forming materials, e.g. super-absorbents
• CPC Class Codes: C08L 33/04 Homopolymers or copolymers of esters C08L43/04 takes precedence
• CPC Class Codes: C08L 5/04 Alginic acid; Derivatives thereof

Abstract

A wound dressing is provided which is made up of a backing layer, an apertured wound facing layer and an intermediate absorbent layer comprising fibers of material which upon contact with moisture will form a gel. The intermediate layer also includes a non-gel forming component, e.g., another fibrous material which can support the formed gels. The backing layer also has a water transmission rate which is greater than its moisture vapor transmission rate.

Claims

1. A wound dressing comprising a backing film, an apertured wound facing layer and an absorbent layer intermediate the backing film and wound facing layer, the backing film having a water transmission rate greater than the moisture vapour transmission rate thereof and the absorbent layer comprising a fibrous layer comprising a fibrous component which, on absorbing moisture, undergoes a phase change to form a gel and a component which does not undergo a phase change to form a gel in the presence of water, the water transmission rate of the backing film being at least 4000 gm⁻

2 24 hr<sup>−

1</sup> at 37°

C. and the moisture vapour transmission rate of the backing film being at least 1000 to 3000 gm<sup>−

2</sup> 24 hr<sup>−

1</sup> at 37°

C. and a relative humidity difference of from 10 to 100%.

2. A dressing as claimed in claim 1 wherein the backing film is an elastomeric polymer.

3. A dressing as claimed in claim 1 wherein the backing film has a thickness of from 15 to 100 μ

m.

4. A dressing as claimed in claim 1 wherein the wound facing layer comprises an elastomeric polymer apertured film or net.

5. A dressing as claimed in claim 1 wherein the elastomeric polymer is a polyether ester, a polyether-polyamide block copolymer, a polyurethane, a styrene-butadiene or styrene-isoprene block copolymer, polyisobutadiene or a ethylene-vinyl acetate copolymer or mixtures or blends thereof.

6. A dressing as claimed in claim 1 wherein the absorbent layer comprises fibres of a density of from 130 to 300 gm⁻

2.

7. A dressing as claimed in claim 1 wherein the gelling component of the absorbent layer comprises fibres of polyacrylic acid or an alginate.

8. A dressing as claimed in claim 1 wherein the non-gelling component is a fibrous material.

9. A dressing as claimed in claim 8 wherein the non-gelling fibrous material is sparingly or substantially non-absorbent.

10. A dressing as claimed in claim 1 wherein the non-gelling component of the absorbent layer comprises cellulosic fibres.

11. A dressing as claimed in claim 1 wherein the backing and wound facing layers are sealed together at the edges of the dressing.

12. A dressing as claimed in claim 1 wherein the wound facing surface of the wound facing layer carries a layer of a skin-friendly pressure sensitive adhesive.