US6372248B1
Expired / Lapsed
US
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Dehydrated hydrogels
Assignee: Innovative Technologies Ltd
•
Filing: 1995-10-30
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Granted: 2002-04-16
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Expires: 2015-10-30
Abstract
Abstract A dehydrated hydrogel incorporating a plasticiser and fibers which have provided cations for cross-linking the dehydrated hydrogel.
Inventors
- 👤 Yimin Qin
- 👤 Denis Keith Gilding
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:32
CPC Classifications
C; C08; C08L; C08L5/00; C08L5/04; A; A61; A61L; A61L26/00; A61L26/0009; A61L26/0023; A61L26/0061; A61L26/008
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
55 words
A water absorbable composition containing less than 20% by weight of water that is suitable for use in the treatment of wounds, comprising a dehydrated hydrogel having a cross-linked macro-molecular network, including a precursor polymer, integrated fibres that have donated cations for cross-linking the precursor polymer to form the cross-linked macro-molecular network, and a plasticizer.
Claim 2
Dependent Claim
55 words
A water absorbable composition containing less than 20% by weight of water that is suitable for use in the treatment of wounds, comprising a dehydrated hydrogel having a cross-linked macro-molecular network, including a precursor polymer, integrated fibres that have donated cations for cross-linking the precursor polymer to form the cross-linked macro-molecular network, and a plasticizer.
Claim 3
Dependent Claim
13 words
A composition as claimed in claim 1 in the form of a film.
Claim 4
Dependent Claim
19 words
A composition as claimed in claim 2 wherein the film has a thickness of 20 microns to 1 mm.
Claim 5
Dependent Claim
57 words
A composition as claimed in claim 1 comprising 15 to 40% by weight of fibres forming the dehydrated hydrogel, 10 to 35% by weight of polymer forming the dehydrated hydrogel and 5 to 75% by weight of plasticiser, the percentages being based on the total weight of fibres and polymer forming the dehydrated hydrogel and of plasticiser.
Claim 6
Dependent Claim
33 words
A composition as claimed in claim 4 wherein the fibres and polymer forming the dehydrated hydrogel together provide about 40-60% by weight on the same weight basis as defined in claim 4 .
Claim 7
Dependent Claim
21 words
A composition as claimed in claim 1 wherein the amount of fibres exceeds the amount of polymer forming the dehydrated hydrogel.
Claim 8
Dependent Claim
19 words
A composition as claimed in claim 6 wherein the weight ratio of fibres:polymer forming the dehydrated hydrogel is 1.5-3:1.
Claim 9
Dependent Claim
18 words
A composition as claimed in claim 1 wherein the fibres have a length of 1 to 80 mm.
Claim 10
Dependent Claim
18 words
A composition as claimed in claim 1 wherein the fibres have a thickness of 10 to 50 microns.
Claim 11
Dependent Claim
19 words
A composition as claimed in claim 1 wherein the plasticiser is glycerol, polyethylene glycol, sorbitol or a PEO/PPO polymer.
Claim 12
Dependent Claim
18 words
A composition as claimed in claim 1 in which said dehydrated hydrogel in a dehydrated form incorporates acemannan.
Claim 13
Dependent Claim
48 words
The composition of claim 11 wherein said dehydrated hydrogel is derived from polymers selected from the group consisting of sodium alginate, sodium carboxymethyl cellulose, sodium pectinate, sodium O-carboxymethyl chitosan (OCC), sodium N,O-carboxymethyl chitosan (NOCC), sodium polyacrylate, and naturally occurring gums and synthetic polymers containing pendant carboxylic acid groups.
Claim 14
Dependent Claim
21 words
The compositions of claim 1 wherein said dehydrated hydrogel is derived from sodium alginate and said fibres are calcium alginate fibres.
Claim 15
Independent Claim
124 words
A method of producing a water absorbable composition containing less than 20% by weight of water that is suitable for use in the treatment of wounds, comprising (i) dispersing fibres into an aqueous solution of a hydrogel precursor material incorporating plasticiser, said fibres being capable of donating cations to cross-link said hydrogel precursor material to form a hydrogel; (ii) effecting formation of a hydrogel by cross-linking of the hydrogel precursor material by cations donated from said fibres so as to form a hydrogel product containing said hydrogel and product fibres derived from the fibres that have donated cations for effecting cross-linking; and (iii) evaporating water from said hydrogel product to produce said composition in the form of a dehydrated hydrogel containing said product fibres.
Claim 16
Independent Claim
124 words
A method of producing a water absorbable composition containing less than 20% by weight of water that is suitable for use in the treatment of wounds, comprising (i) dispersing fibres into an aqueous solution of a hydrogel precursor material incorporating plasticiser, said fibres being capable of donating cations to cross-link said hydrogel precursor material to form a hydrogel; (ii) effecting formation of a hydrogel by cross-linking of the hydrogel precursor material by cations donated from said fibres so as to form a hydrogel product containing said hydrogel and product fibres derived from the fibres that have donated cations for effecting cross-linking; and (iii) evaporating water from said hydrogel product to produce said composition in the form of a dehydrated hydrogel containing said product fibres.
Claim 17
Dependent Claim
48 words
A method as claimed in claim 14 wherein the hydrogel precursor material is selected from the group consisting of sodium alginate, sodium carboxymethyl cellulose, sodium pectinate, sodium O-carboxymethyl chitosan (OCC), sodium N,O-carboxymethyl chitosan (NOCC), sodium polyacrylate, and naturally occurring gums and synthetic polymers containing pendant carboxylic acid groups.
Claim 18
Dependent Claim
24 words
A method as claimed in claim 14 wherein the fibres contain Ca 2+ , Zn 2+ or cations which also act as enzyme cofactors.
Claim 19
Dependent Claim
14 words
A method as claimed in claim 16 wherein the fibres are calcium alginate fibres.
Claim 20
Dependent Claim
15 words
A method as claimed in claim 17 wherein the hydrogel precursor material is sodium alginate.
Claim 21
Independent Claim
129 words
A method of producing a water absorbable composition containing less than 20% by weight of water that is suitable for use in the treatment of wounds, comprising (i) dispersing calcium alginate fibres into an aqueous solution of sodium alginate incorporating plasticiser, said calcium alginate fibres being capable of donating calcium ions to cross-link said sodium alginate to form a hydrogel; (ii) effecting formation of a hydrogel by cross-linking of the sodium alginate by calcium ions donated from said fibres so as to form a hydrogel product containing said hydrogel and product fibres derived from said calcium alginate fibres cations that have donated cations for effecting cross-linking; and (iii) evaporating water from said hydrogel product to produce said composition in the form of a dehydrated hydrogel containing said product fibres.
Claim 22
Independent Claim
129 words
A method of producing a water absorbable composition containing less than 20% by weight of water that is suitable for use in the treatment of wounds, comprising (i) dispersing calcium alginate fibres into an aqueous solution of sodium alginate incorporating plasticiser, said calcium alginate fibres being capable of donating calcium ions to cross-link said sodium alginate to form a hydrogel; (ii) effecting formation of a hydrogel by cross-linking of the sodium alginate by calcium ions donated from said fibres so as to form a hydrogel product containing said hydrogel and product fibres derived from said calcium alginate fibres cations that have donated cations for effecting cross-linking; and (iii) evaporating water from said hydrogel product to produce said composition in the form of a dehydrated hydrogel containing said product fibres.
Claim 23
Independent Claim
170 words
A method of producing a water absorbable composition containing less than 20% by weight of water that is suitable for use in the treatment of wounds, comprising (i) dispersing fibres into an aqueous solution of a hydrogel precursor material incorporating plasticiser, said fibres being capable of donating cations to cross-link said hydrogel precursor material to form a hydrogel; (ii) casting the composition resulting from step (i) into a form for producing a film in step (iii) (iii) effecting formation of a hydrogel by cross-linking of the hydrogel precursor material by cations donated from said fibres so as to form a film of a hydrogel product containing said hydrogel and product fibres derived from the fibres that donated cations for effecting cross-linking; and (iv) evaporating water from said hydrogel product to produce a film of said composition in the form of a dehydrated hydrogel containing said product fibres, said film being capable on absorption of wound exudate of swelling in the thickness dimension without substantial swelling in the other two dimensions.
Claim 24
Independent Claim
170 words
A method of producing a water absorbable composition containing less than 20% by weight of water that is suitable for use in the treatment of wounds, comprising (i) dispersing fibres into an aqueous solution of a hydrogel precursor material incorporating plasticiser, said fibres being capable of donating cations to cross-link said hydrogel precursor material to form a hydrogel; (ii) casting the composition resulting from step (i) into a form for producing a film in step (iii) (iii) effecting formation of a hydrogel by cross-linking of the hydrogel precursor material by cations donated from said fibres so as to form a film of a hydrogel product containing said hydrogel and product fibres derived from the fibres that donated cations for effecting cross-linking; and (iv) evaporating water from said hydrogel product to produce a film of said composition in the form of a dehydrated hydrogel containing said product fibres, said film being capable on absorption of wound exudate of swelling in the thickness dimension without substantial swelling in the other two dimensions.
Claim 25
Dependent Claim
22 words
A method as claimed in claim 20 wherein the hydrogel precursor material is sodium alginate and the fibres are calcium alginate fibres.
Claim 26
Dependent Claim
90 words
A water absorbable composition suitable for use in the treatment of wounds, said composition containing less than 20% moisture and being in the form of a film, the composition comprising a dehydrated hydrogel having a cross-linked macromolecular network, including a precursor polymer, integrated product fibres derived from fibres that have donated cations for cross-linking the precursor polymer to form the cross-linked macromolecular network, and a plasticiser, said film being capable of an absorption of wound exudate of swelling in the thickness dimension without substantial swelling in the other two dimensions.
Claim 27
Dependent Claim
90 words
A water absorbable composition suitable for use in the treatment of wounds, said composition containing less than 20% moisture and being in the form of a film, the composition comprising a dehydrated hydrogel having a cross-linked macromolecular network, including a precursor polymer, integrated product fibres derived from fibres that have donated cations for cross-linking the precursor polymer to form the cross-linked macromolecular network, and a plasticiser, said film being capable of an absorption of wound exudate of swelling in the thickness dimension without substantial swelling in the other two dimensions.
Claim 28
Dependent Claim
24 words
A composition as claimed in claim 22 wherein the precursor polymer is sodium alginate and the product fibres are derived from calcium alginate fibres.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2005-04-15 | 2005-10-15 | 2006-04-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-04-15 | 2009-10-15 | 2010-04-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-04-15 | 2013-10-15 | 2014-04-16 | $7700.00 | Window Closed / Lapsed |