WOUND DRESSING

Abstract

A wound dressing comprising a layer in the form of a strip and comprising gel-forming fibers, the strip having longitudinal lines of stitches formed from a thread and transverse lines of stitches formed from a thread.

Claims

1. A wound dressing having a non-woven web of gel-forming fibers, comprising: longitudinal lines of stitches formed from thread; and transverse lines of stitches formed from thread extending between at least two of the longitudinal lines of stitches to form a stitched column; and at least one stitch free column; wherein, at least two stitched columns are formed and separated by the at least one stitch free column.

2. The wound dressing as claimed in claim 1, wherein the longitudinal lines of stitches are from 1 mm to 10 mm apart and are parallel to a long edge of the wound dressing.

3. The wound dressing as claimed in claim 1, wherein the wound dressing comprises a second non woven web of gel-forming fibers, superposed over the first non woven web of gel-forming fibers wherein the longitudinal lines of stitches join the two non woven web of gel-forming fibers together.

4. The wound dressing as claimed in claim 1, wherein the transverse lines of stitches are stitched through the wound dressing.

5. The wound dressing as claimed in claim 1, wherein the gel-forming fibers comprise one or more of cellulose fibers, chemically modified cellulosic fibers, pectin fibers, alginate fibers, chitosan fibers, hyaluronic acid fibers, polysaccharide fibers and fibers derived from gums.

6. The wound dressing as claimed in claim 1, wherein the thread comprises one or more of nylon, polyolefin, polyurethane, polyester, cellulosic, and modified cellulosic.

7. The wound dressing as claimed in claim 1, wherein the transverse lines of stitches are in the form of a continuous zig-zag.

8. The wound dressing as claimed in claim 1, wherein the dressing is part of a composite dressing.

9. The wound dressing as claimed in claim 1, wherein the wound dressing has a slit in the longitudinal direction in the stitch free gaps configured to remove any loose thread from the transverse lines of the pattern stitch at its longitudinal edges.

10. The wound dressing as claimed in claim 1, wherein the transverse lines of stitches are in the form of a castellated pattern.

11. The wound dressing as claimed in claim 1, wherein the wound dressing forms a strip.

12. A method of manufacturing a wound dressing, comprises the steps of: (i) forming a roll of fabric comprising a non woven web of gel-forming fibers; (ii) forming a first stitched column formed by longitudinal lines of stitches having transverse lines of stitching formed from thread extending between the longitudinal lines of stitches; and (iii) forming a second stitched column spaced from the first stitched column to create stitch free-column between the first and second stitched column.

13. The method as claimed in claim 12, wherein the roll of fabric is formed by knitting a roll of gel-forming fibers.

14. The method as claimed in claim 12, wherein the nonwoven web is made by hydroentangling a web of lyocell fibers and carboxymethylating the web.

15. The method as claimed in claim 12, wherein the method comprises the further step of treating the dressing with a source of silver.

16. The method as claimed in claim 12, wherein the dressing has no loose thread from the transverse stitching at longitudinal edges.

17. The method as claimed in claim 12, wherein the method comprises the further step of superposing a second roll of fabric comprising a non woven web of gel-forming fibers on the first roll of fabric and stitching the first and second roll together.

18. A wound dressing, comprising: a non woven web of gel-forming fibers; transverse lines of stitches extending between longitudinal lines of stitches to form columns; wherein, the transverse lines of stitches are finished at an edge of at least two longitudinal lines of stitches, and wherein the transverse lines of stitches are stitched through the wound dressing.

19. The wound dressing as claimed in claim 18, wherein the gel-forming fibers comprise one or more of spun cellulose fibers, chemically modified cellulosic fibers, pectin fibers, alginate fibers, chitosan fibers, hyaluronic acid fibers, other polysaccharide fibers and fibers derived from gums.

20. The wound dressing as claimed in claim 18, wherein the thread comprises one or more of nylon, polyolefin, polyurethane, polyester, cellulosic, or modified cellulosic.

Description

DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1 is a view of a layer of gel-forming fibers in the form of a roll (1) with longitudinal lines of stitching (2) joined by transverse lines of stitching (4) in the form of an angular zig-zag (6) prior to slitting.

[0032] FIG. 2 is a view of a layer of gel-forming fibers in the form of a roll with longitudinal lines of stitching (2) and transverse lines of stitching (4) in the form of a castellated pattern (12) prior to slitting.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] FIG. 1 shows a nonwoven roll (1) of gel-forming fibers made by a needle felting carding technique to form a web. Optionally, the roll (1) can have an antimicrobial material incorporated into it and, in particular, silver by the method described in WO 02/43743. The roll is stitched in the longitudinal direction with lines of stitching in Tencel yarn. The longitudinal lines of stitches (2) are supplemented by transverse lines of stitching (4) in the form of continuous, angular zig-zags (6) which extend between adjacent longitudinal lines of stitches. In this way stitch free gaps (8) are left between columns (10) of longitudinal stitching. The roll is slit in the longitudinal direction in the stitch free gaps (8) to form ribbons.

[0034] FIG. 2 shows a nonwoven roll (1) similar to that shown in FIG. 1 except that the continuous zig-zag of transverse stitches (4) is made in a castellated pattern (12) between the longitudinal lines of stitches (2) and joins them together. The roll is slit in the longitudinal direction in the stitch free gaps (8) to form ribbons.

[0035] Preferred embodiments of the invention will now be described with reference to the following examples:

Example 1

Dressing A

[0036] A wound dressing was made from a roll of gel-forming fibers as described for the dressing of FIG. 1. The roll had lines of longitudinal stitching spaced 5 mm apart. The column width was 2.5 cm. Ribbons were cut from each roll by slitting in a longitudinal direction at the gaps between the columns in the transverse stitching.

Dressing B

[0037] An alternative wound dressing was made by superposing two rolls of gel-forming fibers as described for Dressing A and stitching as described for Dressing A.

Dressing C

[0038] An alternative wound dressing was made by eliminating the transverse stitching of Dressing A.

Dressing D

[0039] Was formed from 100 gsm Aquacel a nonwoven dressing made from fibers of carboxymethyl cellulose manufactured by ConvaTec Inc.

[0040] Test samples were cut from the stitched rolls to have the dimensions 25 mm wide by 100 mm long for the wet samples and 25 mm wide by 75 mm long for the dry samples. The tensile strength of the gelled and dry samples were measured in the longitudinal and transverse direction in the following manner.

Dry Tensile Testing

[0041] Samples were conditioned at 20 C.2 C. and 65%4% relative humidity for a minimum period of 24 hours. The samples were secured in the pneumatic jaws of a Zwick fitted with a 100 N load cell. The sample was elongated at a speed of 100 mm/min until a 75% reduction in the sample's maximum force was measured.

Wet Tensile Testing.

[0042] Samples were conditioned at 20 C.2 C. and 65%4% relative humidity for a minimum period of 24 hours. 2 ml of a sodium and calcium chloride solution BP (British Pharmacopeia) was dispensed via a pipette onto the center of the sample and left for a period of 1 minute. The sample was secured within the pneumatic jaws of a Zwick U.T.M. fitted with a 100 N load cell. The sample was elongated at a speed of 100 mm/min until a 75% reduction in the sample's maximum force was measured.

[0043] The results are given below where MD=Machine Direction and TD=Transverse Direction.

TABLE-US-00001 Property Dry Tensile Wet Tensile Measurement MD N/cm TD N/cm MD N/cm TD N/cm Dressing D 5.33 16.19 0.16 0.42 Dressing B 8.04 20.82 4.51 4.39 Dressing C 13.51 15.75 8.00 0.44 Dressing A 12.19 30.78 8.05 4.45

[0044] These results show the improvement in tensile strength in transverse stitched samples.

Example 2

[0045] Dressing A was used to pack a tracking wound. On removal from the wound the ribbon dressing was fully hydrated with wound fluid yet had maintained its structure. The dressing was easily removed from the wound in one piece.