ABSORBENT WOUND DRESSING

Abstract

The present invention concerns extensible absorbent wound dressings. The wound dressing has a wound contact layer having a proximal surface facing toward the wound and a distal surface facing away from the wound, and a backing layer having a proximal surface facing toward the wound and a distal surface facing away from the wound, the backing layer having an absorbent region located on a proximal surface thereof, the absorbent region comprising a plurality of discrete absorbent members, wherein the backing layer is configured to be positioned over the wound contact layer, such that the absorbent region is located adjacent to the distal surface of the wound contact layer, and wherein the absorbent region and the wound contact layer are configured to be detached at least in an area inside a perimeter of the absorbent region. The absorbent wound dressings of the present invention can be used to dress so-called truly three-dimensional anatomical areas, such as for example a knee or an elbow.

Claims

1. A wound dressing for application to a wound, comprising: a wound contact layer having a proximal surface facing toward the wound and a distal surface facing away from the wound, and a backing layer having a proximal surface facing toward the wound and a distal surface facing away from the wound, the backing layer having an absorbent region located on a proximal surface thereof, the absorbent region comprising a plurality of discrete absorbent members, wherein the backing layer is configured to be positioned over the wound contact layer, such that the absorbent region is located adjacent to the distal surface of the wound contact layer, and wherein the absorbent region and the wound contact layer are configured to be detached at least in an area inside a perimeter of the absorbent region.

2. A wound dressing according to claim 1, wherein the wound contact layer has a liquid-distribution region located on the distal surface thereof, such that the absorbent region is located adjacent to the liquid-distribution region.

3. A wound dressing according to claim 1, wherein the absorbent region is attached to the wound contact layer at the perimeter of the absorbent region.

4. A wound dressing according to claim 1, wherein the backing layer is attached to the wound contact layer in an area outside the perimeter of the absorbent region.

5. A wound dressing according to claim 4, wherein the proximal surface of the backing layer extends beyond the perimeter of the absorbent region to define a first border region; and wherein the distal surface of the wound contact layer extends beyond a perimeter of the liquid-distribution region to define a second border region, wherein the backing layer is attached to the wound contact layer in at least a portion of the respective first and second border regions.

6. A wound dressing according to claim 5, wherein the first border region surrounds the absorbent region and the second border region surrounds the liquid-distribution region.

7. A wound dressing according to claim 6, wherein the backing layer and the wound contact layer are attached to each other by adhesion in the first and second border regions, so as to encapsulate the absorbent region and the liquid-distribution region.

8. A wound dressing according to claim 1, wherein the plurality of absorbent members are surrounded by a frame.

9. A wound dressing according to claim 1, wherein adjacent absorbent members are separated by a distance of from 0.1 to 5 mm.

10. A wound dressing according to claim 1, wherein each of the absorbent members has cross-section selected from the list consisting of: circular, triangular, square, rectangular, pentagonal, hexagonal, heptagonal, octagonal, nonagonal, decagonal, and combinations of any two or more of the aforesaid.

11. A wound dressing according to claim 10, wherein each of the absorbent members has a substantially hexagonal cross-section.

12. A wound dressing according to claim 1, wherein the absorbent members are arranged in a repeating pattern.

13. A wound dressing according to claim 12, wherein the absorbent members are arranged in a honeycomb pattern.

14. A wound dressing according to claim 1, wherein the absorbent members have a thickness of from 0.1 to 5 mm.

15. A wound dressing according to claim 1, wherein each of the absorbent members comprises, or consists of, an absorbent material.

16. A wound dressing according to claim 15, wherein the absorbent material is selected from the list consisting of a superabsorbent material, fluff pulp, carboxymethylcellulose, alginate, chitosan salt, polyurethane, and combinations of any one or more of the aforesaid.

17. A wound dressing according to claim 16, wherein absorbent material comprises a blend of a superabsorbent material and a fluff pulp.

18. A wound dressing according to claim 4, wherein the liquid-distribution region comprises one or more fenestrations.

19. A wound dressing according to claim 4, wherein the liquid-distribution region comprises a hydrophilic material.

20. A wound dressing according to claim 19, wherein the liquid-distribution region comprises a polyurethane foam.

21. A wound dressing according to claim 1, wherein the wound contact layer has a trilaminate structure.

22. A wound dressing according to claim 1, wherein the wound contact layer comprises one or more perforations.

23. A method of manufacturing a wound dressing comprising the steps of: providing a backing layer having a proximal surface facing toward the wound and a distal surface facing away from the wound, locating an absorbent region on the proximal surface of the backing layer, such that the proximal surface of the backing layer extends beyond the perimeter of the absorbent region to define a first border region, the absorbent region comprising a plurality of discrete absorbent members; providing a wound contact layer having a proximal surface facing toward the wound and a distal surface facing away from the wound; locating a liquid-distribution region on the distal surface of the wound contact layer, such that the distal surface of the wound contact layer extends beyond a perimeter of the liquid-distribution region to define a second border region; attaching the backing layer and the wound contact layer in at least a portion of the respective first and second border regions such that the absorbent region and the liquid-distribution region are adjacent to each other, and wherein the absorbent region and the liquid-distribution region are detached in the area inside the perimeter of the absorbent region.

24. A wound dressing as claimed in claim 1 for use in absorbing fluid discharged from a physiological target, or for use in stemming a flow of a fluid from a physiological target site.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0203] In order that the invention may be more clearly understood, one or more embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

[0204] FIG. 1: shows a cross-section view of a first embodiment of a wound dressing.

[0205] FIG. 2: shows a cross-section view of a second embodiment of a wound dressing comprising a liquid-distribution region.

[0206] FIG. 3: shows a cross-section view of a third embodiment of a wound dressing comprising a perforated wound contact layer.

[0207] FIG. 4: shows an exploded view of the wound dressing depicted in FIG. 3.

[0208] FIG. 5: shows a cross-section view of a fourth embodiment of a wound dressing comprising a trilaminate wound contact layer.

[0209] FIG. 6: shows a cross-section view of a fifth embodiment of a wound dressing

[0210] FIG. 7: shows an underside view of a backing layer and absorbent region.

[0211] FIG. 8: graphically shows the extensibility of a wound dressing according to the present invention.

[0212] Referring to FIG. 1, there is shown a wound dressing 1 comprising a wound contact layer 2 and a backing layer 3.

[0213] The backing layer 3 has a proximal surface 4 that faces towards the wound to which the wound dressing 1 is to be applied. The backing layer 3 also has a distal surface 5 that faces away from the wound to which the dressing 1 is to be applied.

[0214] The backing layer 3 in this embodiment is formed of a polyurethane film. The polyurethane film has a weight of 5-40 gsm. The backing layer 3 permits transpiration of exudate from the dressing into the external environment.

[0215] The backing layer 3 has an absorbent region 6 located on its proximal surface 4. The absorbent region 6 has a perimeter 7, defining an area 8 inside the perimeter 7.

[0216] The absorbent region 6 comprises a plurality of absorbent islands 9. In this embodiment, the absorbent islands 9 comprise an air-laid fabric of a poly(acrylic) acid based superabsorbent and fluff pulp blend. The absorbent islands 9 are attached to the proximal surface 4 of the backing layer 3 using an adhesive (not shown) applied to the proximal surface 4 of the backing layer 3. The adhesive coating on the proximal surface 4 of the backing layer 3 is discontinuous, such that it is substantially only applied in the locations of the absorbent islands 9.

[0217] The absorbent islands 9 are evenly spaced apart in the absorbent region 6. In use, when wound exudate passes through the wound contact layer 2 it will be absorbed by the absorbent islands 9.

[0218] The backing layer 3 extends beyond the perimeter 7 of the absorbent region 6 to define a first border region 10. The first border region 10 extends around the absorbent region 6, in an area outside the perimeter of the absorbent region 6, such that the absorbent region 6 is located centrally on the proximal surface 4 of the backing layer 3. An adhesive (not shown) is applied to the proximal surface 4 of the backing layer 3 in the first border region 10.

[0219] The wound contact layer 2 has a proximal surface 11 that faces towards the wound to which the wound dressing 1 is to be applied. The wound contact layer 2 also has a distal surface 12 that faces away from the wound to which the dressing 1 is to be applied. The wound contact layer 2 in this embodiment is formed of a polyurethane film.

[0220] The backing layer 3 is positioned over the wound contact layer 2, such that the absorbent region 6 is located directly adjacent to the distal surface 12 of the wound contact layer 2. The backing layer 3 is attached to the wound contact layer 2 by adhering the first border region 10 to the distal surface 12. With the first border region 10 adhered to the distal surface 12, the absorbent region 6 and the wound contact layer 2 are detached in the area 8 inside the perimeter 7 of the absorbent region 6. Adhering the backing layer 3 to the wound contact layer 2 creates a seal around the absorbent region 6, which reduces the risk of liquid, such as wound exudate, leaking from the absorbent region 6 to an area outside the perimeter 7 and, potentially, an area outside the wound dressing 1.

[0221] Referring to FIG. 2, there is shown a wound dressing 101. The wound dressing 101 further comprises a liquid-distribution region 113.

[0222] The liquid-distribution region 113 is in the form of a layer, having a proximal surface 114 and a distal surface 115.

[0223] In this embodiment, the liquid distribution layer 113 is formed of a polyurethane foam. The liquid-distribution layer 113 has a high lateral and vertical wicking rate to increase the absorption of exudate from the wound site and to transmit wound exudate to the absorbent region 6. In this embodiment, the liquid-distribution layer 113 has a thickness of 1.5 mm.

[0224] The proximal surface 114 of the liquid-distribution layer 113 is located on the distal surface 12 of the wound contact layer 2. The liquid-distribution layer 113 is attached to the distal surface 12 of the wound contact layer 2 using an adhesive (not shown). The adhesive is coated onto the distal surface 2 of the wound contact layer 2 and/or the proximal surface 114 of the liquid-distribution layer 113.

[0225] The wound contact layer 2 extends beyond a perimeter 116 of the liquid-distribution region 113 to define a second border region 117. The second border region 117 extends around the liquid-distribution region 113, in an area outside the perimeter 116 of the liquid-distribution region 113, such that the liquid-distribution region 113 is located centrally on the distal surface 12 of the wound contact layer 2. An adhesive (not shown) is applied to the distal surface 12 of the wound contact layer 2 in the second border region 117.

[0226] The backing layer 3 is positioned over the wound contact layer 2 and the liquid-distribution layer 113, such that the absorbent region 6 is located directly adjacent to the distal surface 115 of the liquid-distribution layer 113.

[0227] The backing layer 3 is attached to the wound contact layer 2 by adhering the first border region 10 to the second border region 117, encapsulating the absorbent region 6 and the liquid-distribution region 113. Adhering the backing layer 3 to the wound contact layer 2 creates a seal around the absorbent region 6, which reduces the risk of liquid, such as wound exudate, leaking from the absorbent region 6 to an area outside the perimeter 7 and, potentially, an area outside the wound dressing 101.

[0228] With the first border region 10 adhered to the second border region 117, the absorbent region 6 and the liquid-distribution region 113 are detached in the area 8 inside the perimeter 7 of the absorbent region 6.

[0229] In use, when the proximal surface 11 of the wound contact layer 2 is placed on a wound, wound exudate will pass through the wound contact layer 2, be distributed throughout the liquid-distribution layer 113 and then absorbed by the absorbent islands 9.

[0230] Referring to FIGS. 3 and 4, there is shown a wound dressing 201. The wound dressing 201 corresponds to the wound dressing 101, but the wound contact layer 202 has a plurality of perforations 218. The perforations 218 aid in the uptake of fluid from the wound site and reduce the adhesion of the wound contact layer 202 to the wound and/or the skin surrounding the wound, thereby aiding in the removal of the dressing from the wound site.

[0231] Furthermore, as best shown in FIG. 4, the absorbent islands 9 have a hexagonal cross-section and are arranged in a honeycomb pattern on the proximal surface 4 of the backing layer 3 in the absorbent region 6.

[0232] Referring to FIG. 5, there is shown a wound dressing 301. The wound dressing 301 corresponds to the wound dressing 101, but the wound contact layer 302 has a trilaminate structure.

[0233] The trilaminate wound contact layer 302 comprises a carrier layer 319, a proximal layer 320, and a distal layer 321. The proximal layer 320 is located on a proximal surface 322 of the carrier layer 319. The distal layer 321 is located on a distal surface 323 of the carrier layer 319.

[0234] In this embodiment, the carrier layer 319 comprises a polyurethane film, the proximal layer 320 comprises an atraumatic polydimethylsiloxane adhesive and the distal layer 321 comprises an acrylic adhesive.

[0235] The distal layer 321 facilitates the adherence of a proximal surface 114 of the liquid-distribution region 113 to the distal surface and also the adherence of the wound contact layer 2 to the backing layer 3 in the border regions 10, 117.

[0236] The trilaminate 302 may contain perforations (not shown), as described in relation to the embodiment of FIG. 3. In such embodiments, the perforations may extend fully through the carrier layer 319, the proximal layer 320 and the distal layer 321.

[0237] The trilaminate wound contact layer 302 extends beyond a perimeter 116 of the liquid-distribution region 113 to define a second border region 117. The second border region 117 extends around the liquid-distribution region 113, in an area outside the perimeter 116 of the liquid-distribution region 113, such that the liquid-distribution region 113 is located centrally on the distal layer 321. An adhesive (not shown) is applied to the distal surface 324 of the distal layer 321 in the second border region 117.

[0238] As described in relation to the embodiment of FIG. 2, the backing layer 3 is positioned over the wound contact layer 302 and the liquid-distribution layer 113, such that the absorbent region 6 is located directly adjacent to the distal surface 115 of the liquid-distribution layer 113.

[0239] The backing layer 3 is attached to the wound contact layer 302 by adhering the first border region 10 to the second border region 117, encapsulating the absorbent region 6 and the liquid-distribution region 113.

[0240] With the first border region 10 adhered to the second border region 117, the absorbent region 6 and the liquid-distribution region 113 are detached in the area 8 inside the perimeter 7 of the absorbent region 6.

[0241] Referring to FIGS. 6 and 7, there is shown a wound dressing 401.

[0242] The wound dressing 401 comprises a frame 425 surrounding the perimeter 7 of the absorbent region 6. The absorbent region 6 is enclosed within the frame 425. The frame 425 is attached to the proximal surface 4 of the backing layer 3.

[0243] The frame 425 has a proximal surface 426. The frame 425 is attached to a distal surface 115 of the liquid-distribution region 113.

[0244] The backing layer 3 is positioned over wound contact layer 2 and liquid-distribution region 113, such that the absorbent region 6 is located directly adjacent to the distal surface 115 of the liquid-distribution region 113. The frame 425 is attached to the liquid-distribution region 115 by adhering the proximal surface 426 to the distal surface 115. With the frame 425 adhered to the distal surface 115, the absorbent region 6 and the liquid-distribution region 115 are detached in the area 8 inside the perimeter 7 of the absorbent region 6.

[0245] In this embodiment shown in FIG. 6, the area of the distal surface 115 of the liquid-distribution region 113 extends beyond the perimeter 7 of the absorbent region 6 and its surrounding frame 425. Of course, in alternative embodiments the area of the distal surface 115 of the liquid-distribution region 113 may not extend beyond the perimeter 7 of the absorbent region 6. In such embodiments, the frame 425 will be adhered directly to the distal surface 12 of the wound contact layer 2.

[0246] In use, the frame serves to reduce the risk of liquid, such as wound exudate, leaking from the absorbent region 6 to an area outside the perimeter 7 of the absorbent region 6 and, potentially, an area outside the wound dressing 401.

[0247] In use, when a human or animal suffers a penetrating wound, the wound dressing 1, 101, 201, 301, 401 is applied to the wound, with the proximal surface 11 of the wound contact layer 2, 202, 302 being placed in direct contact with the wound. Having the absorbent region 6 and the wound contact layer 2, 202, 302 and/or the liquid-distribution region 113 detached in the area 8, in combination with the absorbent region 6 comprising a plurality of discrete absorbent islands 9, enables the wound dressing 1, 201, 301, 401 to stretch and readily conform to the contours of the anatomical area to which the wound dressing 1 is being applied. Once in place, the wound dressing 1 is able to stretch with the patient's bodily movements as necessary.

Example

[0248] In order to evaluate the extensibility of a wound dressing according to the present invention, the following wound dressing construction was tested according to the test method set out below.

[0249] The assembled wound dressing (Example 1) comprised: [0250] i. a polyurethane film backing layer 3 with a discontinuous coating of acrylic adhesive on a proximal surface thereof; [0251] ii. a perforated wound contact layer 302 having a trilaminate construction comprising a carrier layer 319 of polyurethane film, a proximal layer 320 of atraumatic polydimethylsiloxane adhesive and a distal layer 321 of acrylic adhesive; [0252] iii. an absorbent region 6 consisting of a plurality of absorbent islands 9 secured to the discontinuous coating of acrylic adhesive on the proximal surface of the backing layer; [0253] iv. a liquid-distribution layer 113 comprising a polyurethane foam attached to the distal surface of the wound contact layer 2; and [0254] v. the absorbent region 6 and the liquid distribution region 115 are adjacent to each other but not attached.

[0255] A comparison wound dressing, Control A, was constructed with the same construction as Example 1 above, although the absorbent region comprised a single continuous absorbent region, and the absorbent region and the liquid distribution region were adjacent to each other and attached.

[0256] A comparison wound dressing, Control B, was constructed with the same construction as Control A, although the absorbent region and the liquid distribution region were adjacent but not attached.

[0257] A comparison wound dressing, Control C, was constructed with the same construction as Control A above, although the absorbent region comprised a plurality of absorbent islands.

[0258] The below test method determines the extensibility and conformability of the dressing.

[0259] Test Method:

[0260] (a) clamp the wound dressing into the jaws of a tensile strength testing machine (Mecmesin® MultiTest-i) by the edges of the wound dressing;

[0261] (b) extend the dressing by 5% using an extension rate of 300 mm/min;

[0262] (c) record the load applied to the wound dressing at this extension.

[0263] The above test method was repeated six times for each sample and the results are shown in Table 1 below.

TABLE-US-00001 TABLE 1 Sample Test Extensibility (1/N) Control A 1 0.048 2 0.027 3 0.051 4 0.052 5 0.043 6 0.045 Mean 0.044 Standard Deviation 0.009 Control B 1 0.039 2 0.037 3 0.035 4 0.034 5 0.033 6 0.091 Mean 0.045 Standard Deviation 0.023 Control C 1 0.090 2 0.091 3 0.103 4 0.092 5 0.096 6 0.093 Mean 0.094 Standard Deviation 0.005 Example 1 1 0.175 2 0.169 3 0.172 4 0.174 5 0.170 6 0.139 Mean 0.166 Standard Deviation 0.014

[0264] The extensibility of the wound dressing construction according to the present invention (Example 1) in comparison with Control wound dressings A, B and C is shown graphically in FIG. 8.

[0265] Example 1 showed an average increase in extensibility of 277% over Controls A, B and C. Moreover, the test results demonstrate that the combination of a detached absorbent region and liquid-distribution region and an absorbent region comprising a plurality of absorbent islands has a synergistic effect on the extensibility of the dressing. As shown in FIG. 8, these features, when added independently, only account for a 2% (Control B) and 114% (Control C) increase in extensibility respectively.

[0266] The embodiments are described above by way of example only. Many variations are possible without departing from the scope of protection afforded by the appended claims.