Patent EP0106004A1 successfully refreshed from Google Patents.
US5420197A
Expired / Lapsed
US
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Gels formed by the interaction of polyvinylpyrrolidone with chitosan derivatives
Assignee: Hydromer Inc
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Filing: 1994-01-13
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Granted: 1995-05-30
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Expires: 2014-01-13
Abstract
Abstract A composition includes a stable gel of neutralized chitosan and poly(N-vinyl lactam), the poly(N-vinyl lactam) having a K value of at least about 60 and mole equivalents of acid groups above about 1.4 from ring-opened pyrrolidones. The composition may also include a substrate and various additives incorporated with the gel. A method for making the gel includes mixing the chitosan and poly(N-vinyl lactam) in aqueous solution and curing. Products include wound packings, wound dressings, burn dressings, drug delivery dressings, cosmetic face masks and cosmetic wrap dressings.
Inventors
- 👤 Donald H. Lorenz
- 👤 Connie C. Lee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:06
CPC Classifications
A; A61; A61K; A61K8/00; A61K8/02; A61K8/04; A61K8/042; A61K47/00; A61K47/30; A61K47/32; A61K47/36; A61K8/0208; A61K8/0212; A61K8/18; A61K8/72; A61K8/73; A61K8/736; A61K8/81; A61K8/817; A61K8/8176; A61K9/00; A61K9/0012; A61K9/0014; A61L; A61L15/00; A61L15/16; A61L15/22; A61L15/225; A61Q; A61Q19/00; C; C08; C08L; C08L39/00; C08L39/04; A61K2800/00; A61K2800/40; A61K2800/59; A61K2800/594
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
37 words
A dermatologically-compatible composition comprising a hydrophilic gel which comprises a blend of a neutralized chitosan and a hydrophilic poly(N-vinyl lactam) having a K value of at least 60 and above 1.4 mole equivalents of available acid groups.
Claim 2
Dependent Claim
37 words
A dermatologically-compatible composition comprising a hydrophilic gel which comprises a blend of a neutralized chitosan and a hydrophilic poly(N-vinyl lactam) having a K value of at least 60 and above 1.4 mole equivalents of available acid groups.
Claim 3
Dependent Claim
15 words
The composition of claim 1 wherein the poly(N-vinyl lactam) comprises polyvinylpyrrolidone homopolymer, copolymer or terpolymer.
Claim 4
Dependent Claim
21 words
The composition of claim 1 wherein the gel comprises a poly(N-vinyl lactam)/chitosan weight ratio of from about 12/1 to about 2/1.
Claim 5
Dependent Claim
34 words
The composition of claim 1 wherein the gel is prepared in an aqueous solution at a total polymer concentration of from about 5 weight percent to about 20 weight percent poly(N-vinyl lactam) and chitosan.
Claim 6
Dependent Claim
17 words
The composition of claim 4 wherein the solution comprises water or a mixture of water and alcohol.
Claim 7
Dependent Claim
20 words
The composition of claim 1 wherein the poly(N-vinyl lactam) has mole equivalents of available acid groups of at least 2.0.
Claim 8
Dependent Claim
12 words
The composition of claim 1 which further comprises at least one substrate.
Claim 9
Dependent Claim
24 words
The composition of claim 7 wherein the substrate is selected from a group consisting of polymer film, collagen film, woven fabric, and non-woven fabric.
Claim 10
Dependent Claim
12 words
The composition of claim 7 wherein the substrate is a polyurethane film.
Claim 11
Dependent Claim
12 words
The composition of claim 7 wherein the substrate is a polyester film.
Claim 12
Dependent Claim
10 words
The composition of claim 7 wherein the substrate is stretchable.
Claim 13
Dependent Claim
12 words
The composition of claim 7 wherein the substrate is a release liner.
Claim 14
Dependent Claim
14 words
The composition of claim 1 wherein the gel comprises at least one additional ingredient.
Claim 15
Dependent Claim
12 words
The composition of claim 13 wherein the additional ingredient is a surfactant.
Claim 16
Dependent Claim
14 words
The composition of claim 13 wherein the additional ingredient is releasable from the gel.
Claim 17
Dependent Claim
12 words
The composition of claim 15 wherein the additional ingredient is a fragrance.
Claim 18
Dependent Claim
13 words
The composition of claim 15 wherein the additional ingredient is a biologically-active material.
Claim 19
Dependent Claim
36 words
The composition of claim 17 wherein the additional ingredient is selected from a group consisting of nitroglycerine, scopolamine, pilocarpine, ergotamine tartrate, phenylpropanolamine, theophylline, tetracycline, neomycin, oxytetracycline, triclosan, sodium cefazolin, silver sulfadiazine, salicylates, nicotinates, capsaicin and benzocaine.
Claim 20
Independent Claim
91 words
A method for preparing a stable, mildly tacky, hydrophilic gel comprising mixing an aqueous dissolved poly(N-vinyl lactam) homopolymer or copolymer having a K value of at least 60 and above 1.4 mole equivalents of available acid groups and an aqueous solution of neutralized chitosan in a poly(N-vinyl lactam)/chitosan ratio of from about 12/1 to about 2/1, with a total polymer content above 5 weight percent to produce a blend, and allowing the blend to cure for a time of about 10 seconds to about 2 hours until a gel is formed.
Claim 21
Independent Claim
91 words
A method for preparing a stable, mildly tacky, hydrophilic gel comprising mixing an aqueous dissolved poly(N-vinyl lactam) homopolymer or copolymer having a K value of at least 60 and above 1.4 mole equivalents of available acid groups and an aqueous solution of neutralized chitosan in a poly(N-vinyl lactam)/chitosan ratio of from about 12/1 to about 2/1, with a total polymer content above 5 weight percent to produce a blend, and allowing the blend to cure for a time of about 10 seconds to about 2 hours until a gel is formed.
Claim 22
Dependent Claim
62 words
The method of claim 19 which further comprises treating a poly(N-vinyl lactam) to increase mole equivalents of acid groups to above 1.4 by heating the poly(N-vinyl lactam) in aqueous solution at a temperature of from about 50° C. to about 200° C., at a pressure of from about 15 psi to about 150 psi, for about one-half hour to about 10 days.
Claim 23
Dependent Claim
19 words
The method of claim 20 wherein the aqueous solution has a pH of from about 4 to about 8.
Claim 24
Dependent Claim
15 words
The method of claim 19 which further comprises adding a biologically-active material to the blend.
Claim 25
Dependent Claim
13 words
The method of claim 22 wherein the biologically-active material is an antimicrobial agent.
Claim 26
Dependent Claim
22 words
The method of claim 19 wherein the blend is formed into a dressing by coating or casting the blend onto a substrate.
Claim 27
Dependent Claim
19 words
The method of claim 24 wherein the blend is covered with a second substrate which is a release liner.
Claim 28
Dependent Claim
55 words
The method of claim 19 wherein the blend is formed into a dressing by casting two separate slabs of gel onto two separate substrates, applying a solution of a biologically-active material to a surface of one of the slabs, and compressing the slabs together so that the biologically active material is located between the slabs.
Claim 29
Dependent Claim
20 words
The method of claim 26 wherein the biologically-active material is selected from the group consisting of salicylates, nicotinates and capsaicin.
Claim 30
Dependent Claim
35 words
The composition of claim 1 in the form of a product selected from a group consisting of wound packings, wound dressings, burn dressings, drug delivery dressings, dry films, cosmetic mask dressings and cosmetic wrap dressings.
Claim 31
Dependent Claim
18 words
The composition of claim 28 in the form of a wound packing or cavity dressing without a substrate.
Claim 32
Dependent Claim
12 words
The composition of claim 1 in the form of a dry film.
Claim 33
Dependent Claim
66 words
A stable, hydrophilic gel which comprises a blend of neutralized chitosan and a hydrophilic poly(N-vinyl lactam) having a K value of at least 60 and above 1.4 mole equivalents of available acid groups, the chitosan and poly(N-vinyl lactam) combined in a chitosan/poly(N-vinyl lactam) weight ratio from about 12/1 to about 2/1 in an aqueous solution at a total polymer concentration of at least five weight percent.
Claim 34
Dependent Claim
66 words
A stable, hydrophilic gel which comprises a blend of neutralized chitosan and a hydrophilic poly(N-vinyl lactam) having a K value of at least 60 and above 1.4 mole equivalents of available acid groups, the chitosan and poly(N-vinyl lactam) combined in a chitosan/poly(N-vinyl lactam) weight ratio from about 12/1 to about 2/1 in an aqueous solution at a total polymer concentration of at least five weight percent.
Claim 35
Dependent Claim
25 words
The composition of claim 1 wherein the neutralized chitosan includes a member of the group consisting of pyrrolidone carboxylic acid, glutamic acid, acetate and carboxymethyl.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1998-05-29 | 1998-11-28 | 1999-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-05-29 | 2002-11-28 | 2003-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-05-29 | 2006-11-28 | 2007-05-30 | $7700.00 | Window Closed / Lapsed |