US5380536A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Biocompatible microcapsules
Assignee: The University of Texas System
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Filing: 1991-08-05
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Granted: 1995-01-10
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Expires: 2011-08-05
Abstract
Abstract Biocompatible microcapsules useful for transplanting foreign material into an animal body, and the method of their production, are described, wherein the microcapsules contain an outermost layer of water soluble non-ionic polymers such as PEO to create resistance to cell adhesion on the surface of the microcapsules.
Inventors
- 👤 Jeffrey A. Hubbell
- 👤 Amarpreet S. Sawhney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:02
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/48; A61K9/50; A61K9/5073; A61K47/00; A61K47/50; A61K47/51; A61K47/56; A61K47/59; A61K47/60; A61K47/62; A61K47/64; A61K47/645; A61K47/69; A61K47/6921; A61K47/6925; A61K9/5005; A61K9/5021; A61K9/5031
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
64 words
A method for producing transplantable microcapsules wherein the surface is resistant to cellular attachment comprising forming an outer layer of non-ionic water soluble polymers having molecular weights between 2,000 and 100,000 daltons which have been covalently grafted to at least one of the layers, made of polyamine or polyimine polycationic polymers, of the microcapsule membrane, such that said polycationic polymers remain polycationic after grafting.
Claim 2
Independent Claim
64 words
A method for producing transplantable microcapsules wherein the surface is resistant to cellular attachment comprising forming an outer layer of non-ionic water soluble polymers having molecular weights between 2,000 and 100,000 daltons which have been covalently grafted to at least one of the layers, made of polyamine or polyimine polycationic polymers, of the microcapsule membrane, such that said polycationic polymers remain polycationic after grafting.
Claim 3
Dependent Claim
28 words
The method of claim 1 wherein the non-ionic water soluble polymers are selected from the group consisting of poly(ethylene oxide), poly(vinyl pyrrolidone), poly(ethyl oxazoline), poly(vinyl alcohol) and polysaccharides.
Claim 4
Dependent Claim
24 words
The method of claim 1 wherein the polycationic polymers are selected from the group consisting of polylysine, polyornithine, polyethyleneimine, polyallylamine, and mixed copolymers thereof.
Claim 5
Dependent Claim
15 words
The method of claim 1 wherein the polylysine is between 10,000 d and 75,000 d.
Claim 6
Independent Claim
106 words
A method for making microcapsules comprising using, as an outer layer, non-ionic water soluble polymers having molecular weights between 2,000 and 100,000 daltons that are stable in a biological environment covalently grafted to at least one of the layers of the microcapsule membrane made of polyamine or polyimine polycationic polymers to create a graft copolymer, wherein the grafting comprises the steps of: a) activating the free reactive groups capable of being covalently linked, to a coupling agent on the water soluble non-ionic polymers, and b) coupling the activated water soluble non-ionic polymers to the polycationic polymers; and wherein the resulting graft copolymer retains a polycationic charge.
Claim 7
Independent Claim
106 words
A method for making microcapsules comprising using, as an outer layer, non-ionic water soluble polymers having molecular weights between 2,000 and 100,000 daltons that are stable in a biological environment covalently grafted to at least one of the layers of the microcapsule membrane made of polyamine or polyimine polycationic polymers to create a graft copolymer, wherein the grafting comprises the steps of: a) activating the free reactive groups capable of being covalently linked, to a coupling agent on the water soluble non-ionic polymers, and b) coupling the activated water soluble non-ionic polymers to the polycationic polymers; and wherein the resulting graft copolymer retains a polycationic charge.
Claim 8
Dependent Claim
23 words
The method of claim 5 wherein the reactive groups are selected from the group consisting of hydroxyls, carboxyls, diols, aldehydes, amines, and thiols.
Claim 9
Dependent Claim
28 words
The method of claim 5 wherein the non-ionic water soluble polymers are selected from the group consisting of poly(ethylene oxide), poly(vinyl pyrrolidone), poly(ethyl oxazoline), poly(vinyl alcohol) and polysaccharides.
Claim 10
Dependent Claim
17 words
The method of claim 7 wherein the poly(ethylene oxide) is between 2000 and 50,000 daltons per molecule.
Claim 11
Dependent Claim
24 words
The method of claim 5 wherein the polycationic polymers are selected from the group consisting of polylysine, polyornithine, polyethyleneimine, polyallylamine, and mixed copolymers thereof.
Claim 12
Dependent Claim
15 words
The method of claim 9 wherein the polylysine is between 10,000 d and 75,000 d.
Claim 13
Dependent Claim
12 words
The method of claim 10 wherein the polylysine is approximately 17,500 d.
Claim 14
Dependent Claim
24 words
The method of claim 5 wherein activation is accomplished using an activation agent selected from the group consisting of carbodiimidazole, sulfonyl chlorides and chlorocarbonates.
Claim 15
Dependent Claim
12 words
The method of claim 12 wherein the sulfonyl chloride is trifyl chloride.
Claim 16
Dependent Claim
12 words
The method of claim 12 wherein the sulfonyl chloride is tresyl chloride.
Claim 17
Dependent Claim
12 words
The method of claim 12 wherein the sulfonyl chloride is tosyl chloride.
Claim 18
Dependent Claim
12 words
The method of claim 12 wherein the sulfonyl chloride is pentafluorobenzenesulfonyl chloride.
Claim 19
Dependent Claim
11 words
The method of claim 12 wherein the chlorocarbonate is p-nitrophenyl chlorocarbonate.
Claim 20
Dependent Claim
12 words
The method of claim 12 wherein the chlorocarbonate is 2,4,5 trichlorophenyl chlorocarbonate.
Claim 21
Dependent Claim
11 words
The method of claim 12 wherein the chlorocarbonate is N-hydroxysuccinamide chlorocarbonate.
Claim 22
Dependent Claim
12 words
The method of claim 4 wherein the polylysine is approximately 17,500 d.
Claim 23
Independent Claim
52 words
A method for producing transplantable microcapsules wherein a non-ionic water soluble layer surrounds the microcapsules, comprising covalently grafting water soluble non-ionic polymers having molecular weights between 2,000 and 100,000 daltons to polyamine or polyimine polycationic polypeptides to create a graft copolymer and using said graft copolymer as a layer of the microcapsules.
Claim 24
Independent Claim
52 words
A method for producing transplantable microcapsules wherein a non-ionic water soluble layer surrounds the microcapsules, comprising covalently grafting water soluble non-ionic polymers having molecular weights between 2,000 and 100,000 daltons to polyamine or polyimine polycationic polypeptides to create a graft copolymer and using said graft copolymer as a layer of the microcapsules.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1998-01-09 | 1998-07-11 | 1999-01-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-01-09 | 2002-07-11 | 2003-01-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-01-09 | 2006-07-11 | 2007-01-10 | $7700.00 | Window Closed / Lapsed |