Surgery: splint – brace – or bandage – Bandage structure – Skin laceration or wound cover
Patent
1996-05-16
1999-11-16
Coggins, Wynn Wood
Surgery: splint, brace, or bandage
Bandage structure
Skin laceration or wound cover
602 52, 424447, A61F 1300, A61F 1500
Patent
active
059861649
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to wound dressings, components thereof and to the methods of their manufacture. More specifically this invention relates to dressings suitable for use on exuding wounds, to alginate fibres for use therein and to the methods of their manufacture.
Exuding wounds such as ulcers, pressure sores and burns tend to produce copious volumes of exudate through at least part of the healing process. Many methods of coping with highly exuding wounds have been suggested, for example covering the wound with a highly permeable adhesive film, covering the wound with an adhesive hydrocolloid dressing or employing a dressing comprising an alginate. The use of an alginate wound dressing has proved to have many advantages, for example in terms of aiding healing of the wound as avoidance of damaging friable tissue on removal. Such dressings are described in: PCT/GB89/00706, EP 89917135.6, EP 89910126.5, EP 9120236.4 and PCT/GB92/00792.
Although known alginate dressings have good solubilities, there can be difficulties in removing them from wounds, for example in use they can partially dissolve to a weak gel which has to be washed from the wound. A more soluble dressing would be desirable to ease the removal by washing. Such a dressing has now been discovered.
In addition, it is known that alginate dressings have considerable disadvantages in that they, in common with other forms of dressing, do not sufficiently prevent tissues surrounding highly exuding wounds from becoming macerated. Maceration is not desirable because it can lead to increased friability of tissue. There is therefore a desire to provide a flat alginate dressing which is less likely to allow maceration of tissue surrounding highly exuding wounds. Such a flat dressing has now been discovered.
The present invention provides a wound dressing which comprises alginate characterised in that the alginate has a mannuronate content of 50% to 80%, has a molecular weight of 7000 to 40000 and has a monovalent:polyvalent ion content of from 10 to 30:70 to 90.
It has been found that dressings of the invention and the fibres of which they are composed hydrate rapidly. This greatly helps removal of the dressings and, in the case of flat dressings, significantly reduces the amount of lateral transport of fluid by capilarity. This in turn reduces the amount of exudate transported to the tissue surrounding the exuding wound so that the tendency for that tissue to become macerated is reduced or eliminated.
Alginates are produced by a variety of micro-organisms and marine algae which are the normal commercial source. The alginates being natural materials show considerable variety but are characterised in being block copolymers, the individual monosaccheride units being arranged into groups as blocks of mannuronic (M) and guluronic (G) residues. In addition to the repeating blocks each polymer chain can contain a proportion of alternating M and G monosaccharide units. It has been found that alginates containing 50% to 80% mannuronate can (if having an appropriate molecular weight and ionic content) be of particular use in wound dressings.
Alginates containing 50% to 85% of mannuronate can be obtained from species such as Ascophyllum nodosum, Durvillea Protatonum, Lasonia Nigrescens and Ecklonia Maxima. Blends may be used if desired. Favoured alginates for use in the dressings of this invention will contain from 60% to 80% and preferably from 70% to 75% of mannuronate. A suitable source of such materials is Kelco, Tadworth, Surrey, UK. Suitable grades include manacol of the appropriate molecular weight range.
It has been found that the desirable properties of the dressings are best achieved if the molecular weight of the alginate is from 5000 to 80000, aptly from 7000 to 40000, more suitably from 12000 to 35000 and preferably from 15000 to 30000, for example about 20000 to 25000. A fairly broad distribution of molecular weights within the alginate polymer population is acceptable. The molecular weight referred to is the number average molecular weight. O
REFERENCES:
patent: 5238685 (1993-08-01), Wren
patent: 5482931 (1996-01-01), Thompson
Kershaw David
Mahoney Peter Michael John
Bristol--Myers Squibb Company
Coggins Wynn Wood
Furman Jr. Theodore R.
Kilcoyne John M.
Sadula Jennifer R.
LandOfFree
Alginate wound dressings does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Alginate wound dressings, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Alginate wound dressings will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1326917