US4552138A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dressing material based on a hydrogel, and a process for its production
Assignee: Beiersdorf AG
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Filing: 1983-06-08
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Granted: 1985-11-12
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Expires: 2003-06-08
Abstract
Abstract Dressing material of at least one layer of a polymeric, hydrophilic gel and, where relevant, one or more layers of a carrier material as an intermediate and/or covering layer, wherein the gel consists of 40-50% by weight of a polyvinyl alcohol which is crosslinked and acetalized with formaldehyde and is water-insoluble to the extent of at least 90%, 15-30% by weight of water, 15-45% by weight of one or more polyhydric alcohols with 2-6 C atoms and, where relevant, small amounts of additives and/or auxiliaries.
Inventors
- 👤 Wolfgang Hofeditz
- 👤 Joachim Hornig
- 👤 Werner Karmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:54
CPC Classifications
A; A61; A61L; A61L26/00; A61L26/0009; A61L26/0014
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
78 words
A wound dressing material of at least one layer of a polymeric, hydrophilic gel and, where relevant, one or more layers of a carrier material as an intermediate and/or covering layer, wherein the gel comprises 40-50% by weight of a polyvinyl alcohol which is crosslinked and acetalized with formaldehyde and is water-insoluble to the extent of at least 90%, 15-30% by weight of water, and 15-45% by weight of one or more polyhydric alcohols with 2-6 carbon atoms.
Claim 2
Dependent Claim
78 words
A wound dressing material of at least one layer of a polymeric, hydrophilic gel and, where relevant, one or more layers of a carrier material as an intermediate and/or covering layer, wherein the gel comprises 40-50% by weight of a polyvinyl alcohol which is crosslinked and acetalized with formaldehyde and is water-insoluble to the extent of at least 90%, 15-30% by weight of water, and 15-45% by weight of one or more polyhydric alcohols with 2-6 carbon atoms.
Claim 3
Dependent Claim
35 words
A dressing material as claimed in claim 1, wherein the polyvinyl alcohol has a degree of hydrolysis of 85-90%, and a viscosity of 3-40 cp, in 4% strength aqueous solution before its reaction with formaldehyde.
Claim 4
Dependent Claim
33 words
A dressing material as claimed in claim 1, wherein the gel contains a polyhydric alcohol selected from the group consisting of ethylene glycol, di-glycol, tri-glycol, glycerol, propanediol, butanediol, hexanediol, hexanetriol, and mixtures thereof.
Claim 5
Dependent Claim
17 words
A dressing material as claimed in claim 3, wherein the gel contains 20-30% by weight of propane-1,2-diol.
Claim 6
Dependent Claim
39 words
A dressing material as claimed in claim 1, wherein the gel layer is combined with intermediate and/or covering layers of woven fabrics, knitted fabrics, non-woven fabrics or foams on a synthetic or natural basis to give a laminated product.
Claim 7
Dependent Claim
132 words
A process for the production of a flexible gel layer as claimed in claim 1, which comprises dissolving 40-50% by weight, in each case based on the end product, of polyvinyl alcohol in water, reacting the solution with formaldehyde at elevated temperature, incorporating 15-45% by weight of one or more polyhydric alcohols with 2-6 carbon atoms and, where relevant, small amounts of other additives or auxiliaries into the reaction product which has been precipitated and washed, spreading the resultant soft mass out in the form of a sheet or web in the desired thickness and then subjecting the mass to further heat treatment, for about one hour at about 80°-100° C., for purpose of drying to a residual water content of 15-30% by weight and at the same time conducting further crosslinking.
Claim 8
Dependent Claim
66 words
A process as claimed in claim 6, wherein the gel layer is provided with intermediate and/or covering layers by embedding into the layer of pre-crosslinked gel spread out, or laminating onto this layer, a web of woven fabric, non-woven fabric, film or open-pore foam based on a natural substance or a plastic, and then subjecting the laminated product to heat treatment for drying and further crosslinking.
Claim 9
Dependent Claim
16 words
A dressing material as claimed in claim 2, wherein the said degree of hydrolysis is 88%.
Claim 10
Dependent Claim
15 words
A dressing material as claimed in claim 2, wherein the said viscosity is 18 cp.
Claim 11
Dependent Claim
16 words
A dressing material according to claim 1, wherein the alcohol contains two or three hydroxyl groups.
Claim 12
Dependent Claim
20 words
A dressing material as claimed in claim 1, wherein the alcohol has an average molecular weight of 15,000 to 110,000.
Claim 13
Dependent Claim
20 words
A dressing material as claimed in claim 1, wherein the alcohol has an average molecular weight of 65,000 to 85,000.
Claim 14
Dependent Claim
38 words
A dressing material as claimed in claim 1, wherein additives and/or auxiliaries are present which are selected from the group consisting of medicinal active compounds, physiologically acceptable dyestuffs, physiologically acceptable pigments, physiologically acceptable fragrances and physiologically acceptable fillers.
Claim 15
Dependent Claim
21 words
A dressing material according to claim 12, wherein the active compound is selected from the group consisting of antibiotics and polyvinylpyrrolidone-iodine.
Claim 16
Dependent Claim
22 words
A dressing material according to claim 14, wherein the antibiotic is gentamycin and is contained in an amount of 0.25-0.5% by weight.
Claim 17
Dependent Claim
19 words
A dressing material according to claim 14, wherein said polyvinylpyrrolidone-iodine is contained in an amount of 0.1-0.15% by weight.
Claim 18
Dependent Claim
32 words
In a method of treating a wound on a patient including placing a dressing on the wound of the patient, the improvement which comprises said dressing being the dressing of claim 1.
References Cited (Backward Citations)
US2609347A
Cited
US2647100A
Cited
US2664366A
Cited
US2693438A
Cited
US3287222A
Cited
US3339546A
Cited
US3858379A
Cited
DE2422308A1
Cited
US4098728A
Cited
DE2618613A1
Cited
US4342745A
Cited
EP0095892A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-11-11 | 1989-05-13 | 1989-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-11-11 | 1993-05-13 | 1993-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-11-11 | 1997-05-13 | 1997-11-12 | $7700.00 | Window Closed / Lapsed |