US5085861A
Expired / Lapsed
US
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Bioerodable implant composition comprising crosslinked biodegradable polyesters
Assignee: Beth Israel Deaconess Medical Center
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Filing: 1989-05-12
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Granted: 1992-02-04
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Expires: 2009-05-12
Abstract
Abstract An improved bone cement is comprised of a particulate biocompatible calcium phosphate ceramic and particulate resorbable calcium salt dispersed in a cross-linked biodegradable polyester matrix. The polymer/salt-particle composite exhibits good biomechanical strength/modulus characteristics with surgically acceptable cure times. When used for sustained release of biologically active agents in a physiological environment, controlled release of biological agents that are mixed into the composite can be achieved as the cement biodegrades. When used for bone/implant fixation, or as a filler or cement for bone repair, gradual biodegradation of the cement composite permits, under suitable circumstances, evantual replacement of the cement with developing bone tissue.
Inventors
- 👤 Tobin N. Gerhart
- 👤 Wilson C. Hayes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 03:05
CPC Classifications
C; C08; C08K; C08K3/00; C08K3/18; C08K3/24; A; A61; A61L; A61L24/00; A61L24/001; A61L24/0015; A61L24/0047; A61L24/0073; A61L24/0084; C08K3/32; A61F; A61F2/00; A61F2/02; A61F2/30; A61F2002/30001; A61F2002/30003; A61F2002/3006; A61F2002/30062; A61F2/46; A61F2002/4631; A61F2210/00; A61F2210/0004; A61L2300/00; A61L2300/40; A61L2300/404; A61L2300/406
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
71 words
A composition comprising a particulate biocompatible resorbable calcium salt, a sintered particulate calcium phosphate ceramic and a biologically active agent dispersed in a polymer matrix formed by cross-linking a biodegradable polyester of a dicarboxylic acid comprising fumaric acid and a polyhydric C 2 -C 6 alcohol with about 5 to about 20% by weight of methyl methacrylate, said polyester having a number average molecular weight of about 500 to about 1200.
Claim 2
Dependent Claim
71 words
A composition comprising a particulate biocompatible resorbable calcium salt, a sintered particulate calcium phosphate ceramic and a biologically active agent dispersed in a polymer matrix formed by cross-linking a biodegradable polyester of a dicarboxylic acid comprising fumaric acid and a polyhydric C 2 -C 6 alcohol with about 5 to about 20% by weight of methyl methacrylate, said polyester having a number average molecular weight of about 500 to about 1200.
Claim 3
Dependent Claim
22 words
The composition of claim 1 wherein said biologically active agent forms about 0.1 to about 33 percent by weight of the matrix.
Claim 4
Independent Claim
70 words
A method of repairing living bone which method comprises applying to said living bone a biodegradable bone cement for fixation of bone or joint prostheses, said bone cement comprising a polymer matrix formed by cross-linking a biodegradable polyester of a dicarboxylic acid comprising fumaric acid with about 5 to about 20% by weight of methyl methacrylate, said polyester having a number average molecular weight of about 500 to about 1200.
Claim 5
Independent Claim
70 words
A method of repairing living bone which method comprises applying to said living bone a biodegradable bone cement for fixation of bone or joint prostheses, said bone cement comprising a polymer matrix formed by cross-linking a biodegradable polyester of a dicarboxylic acid comprising fumaric acid with about 5 to about 20% by weight of methyl methacrylate, said polyester having a number average molecular weight of about 500 to about 1200.
Claim 6
Dependent Claim
47 words
The method of claim 3 wherein the biodegradable bone cement comprises methyl methacrylate cross-linked poly(propylene glycol fumarate), a calcium phosphate ceramic and a biocompatible resorbable calcium salt and wherein the weight ratio of the cross-linked polymer to ceramic plus salt is about 2:1 to about 1:5, respectively.
Claim 7
Dependent Claim
121 words
In the method of surgical repair of a bone or joint comprising use of a polymeric cement in contact with living bone, the improvement consisting essentially of preparing the polymeric cement by forming a dispersion of a particulate biocompatible calcium phosphate ceramic and a particulate biocompatible resorbable calcium salt in a mixture of a polymer matrix-forming fluid comprising a (1) a chemically cross-linkable biodegradable polyester of a dicarboxylic acid comprising fumaric acid having a number average molecular weight of about 500 to about 1200 and (2) about 5 to about 20% by weight methyl methacrylate as a cross-linking agent, and initiating a chemical reaction between the polyester and the cross-linking agent prior to using said cement in contact with living bone.
Claim 8
Dependent Claim
121 words
In the method of surgical repair of a bone or joint comprising use of a polymeric cement in contact with living bone, the improvement consisting essentially of preparing the polymeric cement by forming a dispersion of a particulate biocompatible calcium phosphate ceramic and a particulate biocompatible resorbable calcium salt in a mixture of a polymer matrix-forming fluid comprising a (1) a chemically cross-linkable biodegradable polyester of a dicarboxylic acid comprising fumaric acid having a number average molecular weight of about 500 to about 1200 and (2) about 5 to about 20% by weight methyl methacrylate as a cross-linking agent, and initiating a chemical reaction between the polyester and the cross-linking agent prior to using said cement in contact with living bone.
Claim 9
Dependent Claim
13 words
The improvement of claim 5 wherein the biodegradable polyester is poly(propylene glycol fumarate).
Claim 10
Dependent Claim
79 words
An implantable article for use in the sustained release of effective amounts of a biologically active agent into a physiological environment, said delivery system comprising a biologically active agent dispersed in a polymer matrix formed by cross-linking a biodegradable polyester of a dicarboxylic acid comprising fumaric acid and a polyhydric C 2 -C 6 alcohol with about 5 to about 20% by weight methyl methacrylate, said polyester having a number average molecular weight of about 500 to about 1200.
Claim 11
Dependent Claim
79 words
An implantable article for use in the sustained release of effective amounts of a biologically active agent into a physiological environment, said delivery system comprising a biologically active agent dispersed in a polymer matrix formed by cross-linking a biodegradable polyester of a dicarboxylic acid comprising fumaric acid and a polyhydric C 2 -C 6 alcohol with about 5 to about 20% by weight methyl methacrylate, said polyester having a number average molecular weight of about 500 to about 1200.
Claim 12
Dependent Claim
13 words
The article of claim 7 wherein the biologically active agent is an antibiotic.
Claim 13
Dependent Claim
51 words
A bioerodable polymer matrix composition comprising a biodegradable polyester of a dicarboxylic acid comprising fumaric acid and a polyhydric C 2 -C 6 alcohol cross-linked with about 5 to about 20% by weight of methyl methacrylate, said biodegradable polyester having a number average molecular weight of about 500 to about 1200.
Claim 14
Dependent Claim
51 words
A bioerodable polymer matrix composition comprising a biodegradable polyester of a dicarboxylic acid comprising fumaric acid and a polyhydric C 2 -C 6 alcohol cross-linked with about 5 to about 20% by weight of methyl methacrylate, said biodegradable polyester having a number average molecular weight of about 500 to about 1200.
Claim 15
Dependent Claim
16 words
The bioerodable composition of claim 9 wherein the C 2 -C 6 alcohol is propylene glycol.
Claim 16
Dependent Claim
18 words
The composition of claim 1 wherein the biodegradable polyester is a polyester of fumaric acid and propylene glycol.
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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) | 1995-02-03 | 1995-08-05 | 1996-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-02-03 | 1999-08-05 | 2000-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-02-03 | 2003-08-05 | 2004-02-04 | $7700.00 | Window Closed / Lapsed |