Dressing
The invention relates to a chemically modified cellulose based dressing particularly for use in the dressing of wounds but also for use as a packing material. Dressings according to the invention seek to mitigate the problems associated with shrinkage encountered with fibrous dressings made of gel-forming fibres and comprise a compressed body of chemically modified polysaccharide having a density of at least 0.08 g/cm 3 .
1. A wound dressing comprising a compressed body of chemically modified cellulose, wherein the compressed body of chemically modified cellulose comprises a density in the range of 0.10 g.cm −3 to 0.20 g.cm −3 , the compressed body of chemically modified cellulose having a thickness of from 3 mm to 4 mm, wherein the compressed body of chemically modified cellulose comprises a layered structure which is weakly associated, wherein lateral wicking of the dressing comprising the compressed body of chemically modified cellulose is from 10 to 55 mm, and wherein the dressing comprising the compressed body of chemically modified cellulose is capable of contacting a wound.
2. The dressing as claimed in claim 1 wherein the dressing expands on the absorption of wound fluid.
3. The dressing as claimed in claim 2 wherein the ratio of the thickness of the dressing pre hydration to the thickness of the dressing post hydration is greater than 2.
4. The dressing as claimed in claim 3 , wherein the ratio of the thickness of the dressing pre-hydration to the thickness of the dressing post hydration is in the range of 2 to 3.5.
5. The dressing as claimed in claim 1 wherein the body has a lateral shrinkage on absorption of physiological saline of less than 5% when measured by the method described herein.
6. The dressing of claim 1 , wherein the compressed body of chemically modified cellulose has lateral wicking values in the range of 45 to 55 mm.
7. The dressing of claim 1 , wherein the compressed body of chemically modified cellulose has a thickness of from 3 mm to 3.5 mm.
8. The dressing of claim 1 , wherein the compressed body of chemically modified cellulose has a free swell absorption in the range of 20 g/g to 25 g/g.
9. A wound dressing comprising a compressed body of cellulose, which has been chemically modified to increase its absorbency to at least 19 g/g as measured by the free swell method and which expands on absorption of wound fluid, wherein the compressed body of chemically modified cellulose has a density in the range of 0.10 g.cm −3 to 0.20 g.cm −3 , wherein the compressed body of chemically modified cellulose comprises has a layered structure which is weakly associated, wherein the compressed body of chemically modified cellulose has a thickness of from 3 mm to 4 mm, wherein the dressing comprising the compressed body of chemically modified cellulose has a lateral wicking from 10 to 55 mm, and wherein the dressing comprising the compressed body of chemically modified cellulose is capable of contacting a wound.
10. The dressing as claimed in claim 9 wherein the ratio of the thickness of the dressing pre hydration to the thickness of the dressing post hydration is greater than 2.
11. The dressing as claimed in claim 9 wherein the body has a lateral shrinkage on absorption of physiological saline of less than 5% when measured by the method described herein.
12. The dressing as claimed in claim 9 , wherein the ratio of the thickness of the dressing pre hydration to the thickness of the dressing post hydration is in the range of 2 to 3.5.
13. The dressing of claim 9 , wherein the compressed body of chemically modified cellulose has lateral wicking values in the range of 45 to 55 mm.
14. The dressing of claim 9 , wherein the compressed body of chemically modified cellulose has a free swell absorption in the range of 20 g/g to 25 g/g.
15. A process for making a wound dressing, the process comprising: obtaining a compressed body of cellulose having a density in the range of 0.10 to 0.20 g.cm −3 , wherein the compressed body of cellulose comprises associated layers which are weakly associated; and chemically modifying the compressed body of cellulose to increase its absorbency, wherein the chemically modified compressed body of cellulose has a thickness of at least about 3 mm, wherein lateral wicking of the dressing comprising the chemically modified compressed body of cellulose is from 45 to 55 mm, and wherein the dressing comprising the chemically modified compressed body of cellulose is capable of contacting a wound.
16. The process as claimed in claim 15 wherein the chemical modification is carboxymethylation.
17. The process as claimed in claim 15 wherein the compressed body of chemically modified cellulose expands on the absorption of wound fluid.
18. The process of claim 15 , wherein the compressed body of chemically modified cellulose has a thickness of from 3 mm to 4 mm.
19. The process of claim 18 , wherein the compressed body of chemically modified cellulose has a thickness of from 3 mm to 3.5 mm.
20. The process of claim 15 , wherein the compressed body of chemically modified cellulose has a free swell absorption in the range of 20 g/g to 25 g/g.