WOUND DRESSING

Abstract

The present invention relates to a wound dressing composition for use as or in a wound dressing and to methods of making the wound dressing composition. The wound dressing composition comprises an absorbent material, an adhesive material and an anchor material attached to the absorbent material and the adhesive material. The anchor material is operable to maintain a link between the absorbent material and the adhesive material when the wound dressing composition is wet.

Claims

1. A wound dressing composition comprising an absorbent material, an adhesive material and an anchor material attached to the absorbent material and the adhesive material, whereby the anchor material is operable to maintain a link between the absorbent material and the adhesive material when the wound dressing is wet.

2. A composition according to claim 1, wherein the absorbent material is a superabsorbent material.

3. A composition according to claim 2, wherein the superabsorbent material comprises a polymeric material.

4. A composition according to claim 3, wherein the polymeric material is selected from PVA, PEO and polyacrylic acid.

5. A composition according to claim 1, wherein the absorbent material is in the form or fibres.

6. A composition according to claim 5, wherein the fibres form a non-woven layer.

7. A composition according to claim 1, wherein the adhesive material comprises a pressure-sensitive adhesive.

8. A composition according to claim 1, wherein adhesive material is selected from acrylic adhesives and polyurethane adhesives.

9. A composition according to claim 1, wherein the adhesive material covers from around 50-100% of a non-wound facing surface of the anchor material.

10. A composition according to claim 1, wherein the adhesive material provides a border that extends beyond one or more edges of the anchor material and the absorbent material.

11. A composition according to claim 1, wherein the anchor material is a nonabsorbent material that is not water soluble and/or water swellable.

12. A composition according to claim 1, wherein the anchor material is in the form of fibres.

13. A composition according to claim 1, wherein the anchor material comprises polyethylene.

14. A composition according to claim 1, wherein the anchor material is heat-bonded to the absorbent material.

15. A composition according to claim 1, further comprising a backing material, skin contact adhesive and/or wound contact material.

16. A composition according to claim 15, wherein the backing material comprises a polyurethane film.

17. A composition according to claim 15, wherein the wound contact material is hydrophilic.

18. A composition according to claim 17, wherein the wound contact material comprises polyurethane foam.

19. A composition according to claim 1, further comprising a skin protection layer attached to a wound facing surface of the adhesive material.

20. A composition according to claim 19, wherein the skin protection layer comprises silicone.

21. A composition according to claim 19, further comprising a carrier layer located between the skin protection layer and the adhesive material.

22. A composition according to claim 21, wherein the carrier layer comprises a polyurethane film.

23. A composition according to claim 19, wherein the skin protection layer overlaps with a non-wound facing surface of the anchor material, or the skin protection layer overlaps with a part of the wound facing surface of the absorbent material or, if present, the wound facing surface of the wound contact material.

24. A composition according to claim 23, wherein the skin protection layer extends across all of the wound facing surface of the absorbent material or, if present, the wound contact material.

25. A composition according to claim 24, wherein the skin protection layer is perforated.

26. A wound dressing comprising a wound dressing composition according to claim 1.

27. A method of manufacturing a wound dressing composition as described herein, comprising the steps of: (a) providing an absorbent material, (b) attaching the absorbent material to a surface of an anchor material, (c) attaching the opposing surface of the anchor material to an adhesive material, whereby the anchor material is operable to maintain the link between the absorbent material and the adhesive material when the wound composition is wet.

28. A method according to claim 27, wherein the absorbent material is attached to the anchor material by heat-bonding.

29. A use of a wound dressing composition according to claim 1, in absorbing fluid discharged from a physiological target, or in stemming a flow of a fluid discharged from a physiological target site.

30. A wound dressing composition according to claim 1, for use in absorbing fluid discharged from a physiological target, or for use in stemming a flow of a fluid discharged from a physiological target site.

31. (canceled)

Description

[0098] Embodiments of the present invention will now be further described with reference to the following non-limiting examples and accompanying figures in which:

[0099] FIG. 1: is a cross-sectional representation of a wound dressing composition according to an embodiment of the present invention;

[0100] FIG. 2: is a cross-sectional representation of an alternative wound dressing composition of the present invention;

[0101] FIG. 3: is a cross-sectional representation of a wound dressing composition of the present invention comprising a skin protection layer;

[0102] FIG. 4: is a cross-sectional representation of a further alternative wound dressing composition of the present invention comprising a skin protection layer;

[0103] FIG. 5: is a cross-sectional representation of a further alternative wound dressing composition of the present invention comprising a skin protection layer;

[0104] FIG. 6: is a cross-sectional representation of a further alternative wound dressing composition of the present invention;

[0105] FIG. 7: is a cross-sectional representation of the wound dressing composition of FIG. 6 further comprising a skin protection layer;

[0106] FIG. 8: is a graph showing the absorbency of the three test materials with and without compression.

[0107] Referring to FIGS. 1 and 2, there is shown a wound dressing composition (1) comprising a layer of absorbent material (2), a layer of anchor material (3) a layer of adhesive material (4), a backing layer (5) and a wound contact material (6).

[0108] The wound contact material (6) is adjacent to the wound site and will come into direct contact with the wound upon application of the wound dressing composition (1) to a wound. The absorbent material (2) has a wound facing surface (2a) and a non-wound facing surface (2b). The wound contact material (6) is attached to the wound facing surface (2a) of the absorbent material (2) by any of the means described herein. Preferably, the wound contact material (6) is attached to the absorbent material (2) using a powder adhesive. The wound contact layer (6) also serves to prevent or reduce the leaching of material from the absorbent layer (2).

[0109] The anchor material (3) is attached to the non-wound facing surface (2b) of the absorbent material (2). Typically, the anchor material (3) is heat-bonded to the absorbent material (2). As described herein, the bond created between the anchor material (3) and the absorbent material (2) is such that it will not break when the respective materials get wet with wound fluid during use.

[0110] The anchor material (3) is attached to the wound facing surface (4a) of the adhesive material (4) by any of the means described herein. Typically, the adhesive material (4) is a pressure sensitive adhesive. Thus, the anchor material (3) is contacted with the wound facing surface (4a) of the adhesive material (4) and pressure is applied to bring the two materials together.

[0111] The adhesive layer (4) has a backing layer (5) attached to its non-wound facing surface (4b). As with the anchor material (3), the backing layer (5) can be attached to the backing layer (5) by contacting the two materials together and applying pressure.

[0112] As can be seen in both FIGS. 1 and 2, the adhesive layer (4) and the backing layer (5) have a greater cross-sectional area than the anchor material (3), the absorbent material (2) and the wound contact material (6), creating a border portion (7). The wound facing surface (4a) of the adhesive layer (4) in the border portion (7) is, in use, applied directly to the patient's skin surrounding the wound site. Thus, the adhesive layer (4) has the dual purpose of adhering to the anchor layer (3) and the skin of the patient. Again, the border portion (7) of the adhesive layer (4) can be attached to the skin by applying downward pressure to the border portion (7) of the backing layer (5).

[0113] Turning to FIG. 2, the adhesive layer (4) provides less than 100% coverage of the anchor layer (3) or the backing layer (5). In this embodiment, the adhesive layer (4) is made up of regular intervals of adhesive to which the backing layer (5) and anchor layer (3) bind. This has benefits in that there is less adhesive in direct contact with the patient's skin, which will reduce discomfort upon removal of the wound dressing composition (1).

[0114] Referring to FIGS. 3, 4 and 5, there is shown wound dressing compositions (1) comprising a layer of absorbent material (2), a layer of anchor material (3) a layer of adhesive material (4), a backing layer (5), a layer of wound contact material (6) and a silicone layer (8) on a carrier material (9).

[0115] In FIG. 3, the silicone layer (8) is attached to a carrier layer (9) which is in turn attached to the wound facing surface (4a) of the adhesive material (4). The silicone layer (8) and the carrier layer (9) extend outwardly to the outer edge of the adhesive layer (4) and backing layer (5). The silicon layer (8) and the carrier layer (9) both extend inwardly to cover the whole of the border portion (7) and create an overlap (10) with the anchor layer (3). An aperture (11) is provided through which the anchor layer (3) can bind to the wound facing surface (4a) of the adhesive layer (4). The overlap (10) increases the strength and stability of the wound dressing composition (1) as the adhesive layer (4) is attached to both the anchor layer (3) and the silicone layer (8). In use, the silicone layer (8) in the border portion (7) will adhere to the skin surrounding the wound site. Beneficially, the silicone layer (8) can be removed and reapplied with less irritation and pain than the adhesive layer (4).

[0116] In FIG. 4, the silicone layer (8) extends from the edge of the adhesive layer (4), across the border portion (7) and overlaps (12) with the wound facing surface (6a) of the wound contact material (6). The overlap (12) increases the strength and stability of the wound dressing composition (1) as the silicone layer (8) more securely holds the anchor layer (3), the absorbent layer (2) and the wound contact layer (6) in place. Further, the silicone layer (8) will provide a gentle adhesion to the wound site in the area of overlap (12).

[0117] In FIG. 5, the silicone layer (8) extends from the edge of the adhesive layer (4), over the border portion (7) and across the whole of the wound facing surface (6a) of the wound contact layer (6). The silicone layer (8) and the carrier layer (9) contain regular perforations (13). The perforations (13) improve the breathability of the wound dressing composition (1) and also allow wound fluid to flow through to the wound contact layer (6). A benefit to the silicone layer (8) covering the wound facing surface (6a) of the wound contact layer (6) is that it will further prevent the leaching into the wound of any material from the wound contact layer (6) and/or the absorbent layer (2).

[0118] In FIG. 6, the absorbent layer (2) extends to the edge of the dressing (1), as does the anchor layer (3), the adhesive layer (4) and the wound contact layer (6). FIG. 6 also shows the presence of a powder adhesive layer (14) which attaches the absorbent material (2) to the wound contact layer (6).

[0119] FIG. 7 shows the wound dressing of FIG. 6, further comprising a skin protection silicone layer (8) on a carrier layer (9). The silicone layer (8) and the carrier layer (9) extend to the edge of the dressing (1).

[0120] The embodiment shown in FIGS. 6 and 7 is beneficial over the prior art, since the absorbent material (2) can extend to the edge of the dressing (1) and does not need to be encapsulated by an encapsulating material to secure it in place during use. Existing dressings require the absorbent pad to be encapsulated within the dressing area such that on absorption of fluid it does not delaminate from the dressing structure. This is achieved either by encapsulating the absorbent material within an encapsulating material such that the absorbent material is restricted to being smaller in size than the encapsulating material or incorporating an all over wound contact layer that encapsulates the absorbent pad area between the wound contact layer and the outer layer.

[0121] In use, the wound dressing composition (1) of the present invention is applied to a wound by contacting the wound contact layer (6) and/or the silicone layer (8) with the wound site. The wound dressing composition (1) can be affixed to the patient's skin by applying downward pressure to the border portion (7). Wound exudates from the wound will be absorbed by the wound contact layer (6) and drawn through to the absorbent layer (2). This has the effect of drawing fluid away from the wound bed, creating a moisture level at the wound bed that is more conducive to healing.

EXAMPLES

[0122] The wound dressing compositions of the present invention do not delaminate when the composition is exposed to fluid, such as wound exudate. To test this, the following experiment was followed.

[0123] Test Methodology

[0124] An island wound dressing as shown in FIG. 1 was prepared. The wound dressing was made up of a superabsorbent layer (2) of polyacrylate fibres gsm 250, an anchor layer (3) of knitted fibrous polyethylene, an adhesive layer (4) of a pressure-sensitive acrylic adhesive 20 gsm, a backing layer (5) of a polyurethane film, 15 micron thickness and a wound contact layer (6) of a polyurethane foam, 1.5 mm thickness.

[0125] Three 50 mm50 mm section of the island wound dressing were cut out and immersed for a minimum of 24 hours in three separate solutions A, B and C. For comparison purposes, prior art dressings Mepilex Border (Molnlycke Healthcare) and Tielle Plus (Systergenics) were tested. On submersion in the below test fluids, the Mepilex Border and Tielle dressings observed that the backing layers separated from the absorbent layers. This was not observed for the wound dressing of the present invention. When tested as a whole dressing, only the Tielle exhibited separation of the backing material from the absorbent pad materials.

[0126] In the tests, Solution A is 142 mmol sodium ions and 2.5 mmol calcium ions as the chloride salt, Solution B is saline and Solution C is simulated wound fluid (50% peptone water and 50% fetal bovine serum).

[0127] The three sections of wound dressing were then inspected for integrity.

[0128] Finally, the tensile strength of the superabsorbent layer bonded to the acrylic adhesive layer was measured using a tensiometer (>0.5N/25 mm). For the Mepilex Border and Tielle Plus dressings, no results were obtained as the layers had separated. The material of the present invention achieved a range of from 0.65N/25 mm to 1.1N/25 mm.

[0129] An island wound dressing as shown in FIG. 3 was prepared and tested by the same test methodology described above. The silicone layer (8) was attached to a polyurethane film layer (9) which was attached to the wound facing surface (4a) of the adhesive layer (4). The polyurethane layer (9) is the same as the polyurethane backing layer (5).

[0130] The test further included an assessment for any leaching of the superabsorbent layer (2) from the wound dressing composition (1).

[0131] No visual leaching of superabsorbent layer for any of the dressings tested.

[0132] Absorbency was also tested and the results are shown in the graph of FIG. 8.

[0133] It is clear from FIG. 8 that the dressing of the present invention shows good absorbency under compression compared to the comparative dressings Mepilex Border and Tielle Plus.

[0134] It is of course to be understood that the present invention is not intended to be restricted to the foregoing examples which are described by way of example only.