Wound dressings

Details Wound dressings Wound dressings

1995-06-02

1997-09-16

Zuttarelli, P.

Surgery

Means for introducing or removing material from body for...

Treating material applied to or removed from external...

602 48, 602 79, 424447, A61F 1300

Patent

active

056675011

DESCRIPTION:

BRIEF SUMMARY
TECHNICAL FIELD

This invention relates to dressings which provide a good healing environment for wounds.
Good wound healing is characterised by rapid and complete regeneration of the damaged tissue. Considerable efforts have been expended in the study of wound dressings with the aim of finding which dressings are most effective in promoting wound healing. The process of wound healing is complex and is not fully understood. High macrophage activity is desirable, particularly during the early stages of healing, say during the first day or so, to kill bacteria and to remove cell debris and foreign matter. This activity is generally accompanied by inflammation. High fibroblast activity is desirable, particularly during the later stages of healing, for example between the third and seventh days, to produce a high rate of regeneration.
Enhanced concentrations of active free radicals are often found in wounds, in particular small oxygen-containing free radicals such as the hydroxyl radical (OH.), the hydroperoxyl radical (OOH.) and the superoxide anion (O.sub.2..sup.-). The latter two are in protonation equilibrium, with the anion predominating at physiological pH; the hydroperoxyl radical is a more active free radical than the superoxide anion. The presence of these radicals is believed to be advantageous in the early stages of healing, attracting macrophages into the wound and promoting the respiratory burst. Their continued presence is, however, believed to be detrimental. They are thought to promote continued inflammation and so to delay healing and in severe cases to induce tissue necrosis and permanent tissue damage. In contrast, oxidising species without unpaired electrons, such as hydrogen peroxide (H.sub.2 O.sub.2), are believed to be considerably less harmful. Indeed, Burdon, Gill and Rice Evans suggest in Free Rad. Res. Commun., Vol. 7 (1989), at pages 149-159, that low levels of hydrogen peroxide (around 10-8-10.sup.-6 M) stimulate fibroblast proliferation.


BACKGROUND ART

Flohe, Giertz and Bechmann discuss the use of free-radical scavengers as anti-inflammatory drugs in Handbook of inflammation, Volume 5: The Pharmacology of Inflammation, pages 255-281 (Elsevier Science Publishers BV, 1985). Superoxide anion is said to serve an indispensable purpose in the killing of phagocytosed micro-organisms. Superoxide anion and reaction products such as hydroxyl radical are said to be deleterious in the extracellular environment, possibly leading to self-maintenance of the inflammatory reaction and to tissue damage. The authors report the successful treatment of a variety of inflammatory conditions by injection of the enzyme superoxide dismutase (SOD), which catalyses the reaction: free radicals by drugs rather than by enzymes. In particular, the reaction of free radical and scavenger generates a new free radical. If this is as reactive as the original radical, no benefit has been obtained. If it is less reactive, it may migrate away from the wound site and cause damage in a previously healthy area. The authors conclude that scavenging of highly reactive radicals in vivo is neither feasible nor desirable.
U.S. Pat. No. 4,837,024 describes compositions which enhance and promote the wound healing process and which comprise suspensions of the fibrous protein, collagen, and of a polysaccharide, namely a glycosaminoglycan. The glycosaminoglycan is one which exhibits chemotaxis for fibroblasts or endothelial cells; the preferred glycosaminoglycans are said to be heparin, heparan sulphate and alginate, although it should be noted that alginate is not in fact a glycosaminoglycan.
International Patent Application WO 91/11205 describes biopolymers which can be formulated into wound dressings which improve wound healing. The biopolymers are polysaccharides which contain at least 70% mannuronic acid residues, for example certain types of bacterial alginate or of oxidised guar gum or oxidised mannan.
International Patent Application WO91/12267 describes metal:peptide complexes possessing anti-oxidative and anti-inflammat

REFERENCES:
patent: 4781921 (1988-11-01), Smith et al.

Affiliated with

Also associated with

Rating

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 Wound dressings, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Wound dressings will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-214630