Fibres of cospun alginates

Details Fibres of cospun alginates Fibres of cospun alginates

1997-06-30

2000-06-27

Page, Thurman K.

Drug, bio-affecting and body treating compositions

Preparations characterized by special physical form

Web, sheet or filament bases; compositions of bandages; or...

424449, 424484, 424486, 424488, A61K 970

Patent

active

060804203

DESCRIPTION:

BRIEF SUMMARY
The present invention relates to alginate containing fibres which are useful particularly, but not exclusively, in the manufacture of wound dressings.
Alginates are a family of polymers which may be obtained from seaweed and which contain varying proportions of mannuronic and guluronic residues depending on the source of the polymer.
It is established practice to produce alginate fibres by spinning a solution of a soluble form of an alginate polymer into a gelation (or coagulation) bath in which an insoluble form of the alginate precipitates. Typically the soluble form of the polymer is the sodium salt and the bath contains calcium ions to produce insoluble calcium alginate. Fibres produced in this way have high absorbency and are used in the manufacture of wound dressings, e.g. for wet wounds such as pressure sores, leg ulcers, surgical incisions and donor sites where the primary function of the alginate is to absorb exudate.
The present invention relates to modified alginate fibres which are useful in wound dressings.
According to a first aspect of the present invention there is provided fibres comprising an alginate co-spun with at least one water soluble organic polymeric species (other than an alginate).
According to a second aspect of the invention there is provided a method of producing fibres comprising co-spinning a dope which contains dissolved alginate and at least one dissolved organic polymeric species (other than an alginate) into an aqueous coagulation bath which causes precipitation of fibres each comprised of the alginate and said other polymeric species.
The non-alginate polymer is preferably (but not necessarily) one having negative charges along the polymer chain, i.e. a polyanion. Alternatively the polymer may be uncharged.
Preferably the fibres comprise 70-95% by weight alginate and 5-30% by weight of the non-alginate polymer.
The incorporation of the water soluble non-alginate polymeric species into the fibres with the alginate allows useful fibres of modified properties to be obtained, as compared to the properties obtained in the alginate is the sole component of the fibres. The modified properties may, for example, be increased absorbency of the fibres.
Generally the fibres will comprise a major proportion by weight of the alginate, e.g. 50-95% by weight, and a minor proportion of the non-alginate polymeric species. The alginate may be one having a G-content of 35-70% and correspondingly an M-content of 65-30% by weight. Typically the alginate will be such that a 1% solution will have a viscosity of 30-300 cP, preferably 40-100 cP.
If the non-alginate polymeric species contains negatively charged groups, these may be provided, for example, by COO.sup.- or SO.sub.4.sup.2- groups along the polymer chain.
In one embodiment of the invention, alginates may be co-spun with non-alginate species containing COO.sup.- groups along the chain, examples of which include polysaccharides, polycarboxyamino acids it is also possible to use acrylic acid and/or metharcrylic acid, or salts thereof (e.g. the sodium salt). More specific examples include pectin, carboxymethyl cellulose, N--,O-carboxymethyl chitosan (NOCC), carrageenan, xanthan, gellan, polyaspartic acid and polyglutamic acid.
The alginate may be co-spun with a non-alginate polymer containing COO.sup.- groups which results in a fibre having increased absorbency as compared to one prepared from the alginate alone. Examples of such non-alginate polymers which result in increased absorbency include carboxymethyl cellulose, carrageenan, polyacrylic acid and NOCC. Thus fibres of improved absorbency may comprise 70-90% alginate and a total of 5-30% of at least one of CMC, carrageenan, polyacrylic acid and N,O,-carboxymethyl chitosan (NOCC) or O-carboxymethyl chitosan (OCC).
If the alginate is co-spun with pectin, fibres are produced which, when made into (and used) as a wound dressing, soften dry wounds, start autolysis procedures, and assist debridement macrophage stimulation. Preferably the pectin comprises 5-30% (more preferably 10-20%) by

REFERENCES:
patent: 5144016 (1992-09-01), Skjak-Braek
patent: 5230853 (1993-07-01), Colegrove
patent: 5622666 (1997-04-01), Struszczyk
patent: 5660857 (1997-08-01), Haynes

Affiliated with

Also associated with

Rating

Fibres of cospun alginates does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Fibres of cospun alginates, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fibres of cospun alginates will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1782025