US4770665A
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US
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Elastomeric polymer incorporation into implantable biological tissue to inhibit calcification
Assignee: American Hospital Supply Corp
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Filing: 1985-11-05
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Granted: 1988-09-13
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Expires: 2005-11-05
Abstract
Abstract A process for the preparation of implantable biological tissue wherein elastomeric copolymers are incorporated into the tissue in an amount sufficient to increase the durability of the tissue as well as to reduce calcification of the tissue upon implantation. Mitigaton of calcification is retained when the tissue is subjected to flexing, stretching, or similar motion.
Inventors
- 👤 Aws S. Nashef
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 21:02
CPC Classifications
A; A61; A61L; A61L27/00; A61L27/36; A61L27/3683; A61L27/3687; A61L27/14; A61L27/16; C; C08; C08L; C08L51/00; A61L2400/00; A61L2400/02; Y; Y10; Y10S; Y10S623/00; Y10S623/915; Y10S623/916
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
122 words
A process for treating animal biological tissue prior to implantation into an animal to increase the durability of the tissue and to reduce calcification of said tissue after implantation comprising the steps of: (a) fixing said tissue under tissue-fixing conditions; (b) contacting said fixed tissue with a first solution of one or more monomers capable of further polymerization under conditions sufficient to covalently bond said monomer(s) to the tissue; and (c) contacting said tissue with a second solution containing one or more monomers or oligomers under polymerization conditions such that the monomers or oligomers in the second solution polymerize with said covalently bound first monomer(s) to form an elastomeric polymer in an amount effective in reducing calcification of said tissue after implantation.
Claim 2
Dependent Claim
122 words
A process for treating animal biological tissue prior to implantation into an animal to increase the durability of the tissue and to reduce calcification of said tissue after implantation comprising the steps of: (a) fixing said tissue under tissue-fixing conditions; (b) contacting said fixed tissue with a first solution of one or more monomers capable of further polymerization under conditions sufficient to covalently bond said monomer(s) to the tissue; and (c) contacting said tissue with a second solution containing one or more monomers or oligomers under polymerization conditions such that the monomers or oligomers in the second solution polymerize with said covalently bound first monomer(s) to form an elastomeric polymer in an amount effective in reducing calcification of said tissue after implantation.
Claim 3
Dependent Claim
33 words
The process of claim 1 wherein said second monomer or oligomer solution comprises two or more different monomers, at least one of which is an ester of acrylic acid or of methacrylic acid.
Claim 4
Dependent Claim
42 words
The process of claim 2 wherein the ester(s) of acrylic or methacrylic acid is present in amounts of from about 30 to about 100 weight percent of the total weight of the monomers or oligomers in the second monomer or oligomer solution.
Claim 5
Dependent Claim
40 words
The process of claim 3 wherein the ester(s) of acrylic or methacrylic acid is present in amounts of from 50 to 100 weight percent of the total weight of the monomers or oligomers in the second monomer or oligomer solution.
Claim 6
Dependent Claim
78 words
The process of claim 2 wherein the ester(s) of acrylic or methacrylic acid is selected from the group consisting of methyacrylate, methyl methyacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, hydroxy ethyl acrylate, hydroxy ethyl methacrylate, hydroxy propyl acrylate, hydroxy propyl methacrylate, hydroxy butyl acrylate, hydroxy butyl methacrylate, acrylic acid glycerine ester, methacrylic acid glycerine ester, acrylic acid erythritol ester, methacrylic acid erythritol ester, acrylic acid pentaerythritol ester, and methacrylic acid pentaerythritol ester.
Claim 7
Dependent Claim
22 words
The process of claim 1 further comprising the step of removing non-covalently bound monomer from said tissue between steps (b) and (c).
Claim 8
Dependent Claim
29 words
The process of claims 1 or 2 wherein said first monomer is chosen from acrylic acid, methacrylic acid, acrylamide, methacrylamide, esters of acrylic acid, or esters of methacrylic acid.
Claim 9
Dependent Claim
15 words
The process of claim 1 wherein said second monomer solution comprises only one monomer species.
Claim 10
Dependent Claim
15 words
The process of claim 8 wherein the second monomer is an ester of methacrylic acid.
Claim 11
Dependent Claim
31 words
The process of claim 2 wherein said second monomer solution, in addition to said ester derivative(s) of acrylic or methacrylic acid, comprises acrylamide, acrylic acid, methacrylic acid, methacrylamide, or mixtures thereof.
Claim 12
Dependent Claim
36 words
The process of claim 2 wherein the monomer in said first monomer solution is acrylic acid or methacrylic acid, and said second monomer or oligomer solution comprises two or more esters of acrylic or methacrylic acid.
Claim 13
Dependent Claim
34 words
The process of claim 2 wherein the first monomer covalently bound to said tissue is acrylic acid, and the second monomer solution comprises a mixture of esters of acrylic or methacrylic acid, and acrylamide.
Claim 14
Dependent Claim
27 words
The process of claim 1 wherein the second monomer solution contains from about 0.1 to about 10.0 weight percent total of one or more monomers or oligomers.
Claim 15
Dependent Claim
27 words
The process of claim 3 wherein the second monomer solution contains from about 0.5 to about 6 weight percent total of one or more monomers or oligomers.
Claim 16
Dependent Claim
27 words
The process of claim 14 wherein the second monomer solution contains from about 0.5 to about 2.0 weight percent total of one or more monomers or oligomers.
Claim 17
Dependent Claim
14 words
The process of claim 1 wherein said second solution additionally comprises a cross-linking agent.
Claim 18
Dependent Claim
11 words
The process of claim 16 wherein said cross-linking agent is bisacrylamide.
Claim 19
Dependent Claim
15 words
The process of claim 1 wherein said second solution additionally comprises a free radical scavenger.
Claim 20
Dependent Claim
14 words
The process of claim 18 wherein said free radical scavenger is ferrous ammonium sulfate.
Claim 21
Dependent Claim
42 words
The process of claim 1 wherein said tissue is contacted with a free radical initiator between steps (b) and (c) in an amount sufficient to catalyze the polymerization of the covalently-bound first monomers with the monomers or oligomers in said second solution.
Claim 22
Dependent Claim
19 words
The process of claim 20 wherein said free radical initiator is an aqueous solution comprising ammonium persulfate and N,N,N',N'-tetramethylenediamine.
Claim 23
Dependent Claim
37 words
The process of claim 1 further comprising covalently binding a spacer to said fixed tissue between steps (a) and (b) so that the monomer(s) in said first solution is covalently bound to said tissue through the spacer.
Claim 24
Dependent Claim
12 words
The process of claim 22 wherein said spacer is a diamine compound.
Claim 25
Dependent Claim
34 words
The process of claim 23 wherein said diamine compound has the formula R-(NH 2 ) 2 , wherein R is an aliphatic group having a straight, branched or cyclic chain, or an aromatic group.
Claim 26
Dependent Claim
11 words
The process of claim 24 wherein said diamine compound is ethylenediamine.
Claim 27
Dependent Claim
21 words
The process of claim 24 wherein said diamine is covalently bound to said fixed tissue in the presence of a carbodiimide.
Claim 28
Dependent Claim
35 words
The process of claim 1 wherein said biological tissue is a tendon, ligament, heart valve, dura mater, fascia lata, amnion or pericardium taken from a bovine, porcine, horse, sheep, kangaroo, rabbit, or human cadaver source.
Claim 29
Dependent Claim
12 words
The process of claim 1 wherein said tissue is fixed with glutaraldehyde.
Claim 30
Dependent Claim
122 words
A process for treating animal biological tissue prior to implantation in an animal to increase the durability of said tissue and to reduce calcification of said tissue after implantation comprising the steps of: (a) fixing said tissue under tissue-fixing conditions; (b) contacting said tissue with a first solution of a monomer capable of further polymerization for a time sufficient to impregnate said monomer in said tissue; and (c) contacting said tissue with a second monomer solution containing one or more monomers or oligomers, under polymerization conditions such that the monomers or oligomers in said second solution polymerize with said first monomer impregnated within said tissue to form an elastomeric polymer in an amount effective in reducing calcification of said tissue after implantation.
Claim 31
Dependent Claim
122 words
A process for treating animal biological tissue prior to implantation in an animal to increase the durability of said tissue and to reduce calcification of said tissue after implantation comprising the steps of: (a) fixing said tissue under tissue-fixing conditions; (b) contacting said tissue with a first solution of a monomer capable of further polymerization for a time sufficient to impregnate said monomer in said tissue; and (c) contacting said tissue with a second monomer solution containing one or more monomers or oligomers, under polymerization conditions such that the monomers or oligomers in said second solution polymerize with said first monomer impregnated within said tissue to form an elastomeric polymer in an amount effective in reducing calcification of said tissue after implantation.
Claim 32
Dependent Claim
33 words
The process of claim 29 wherein said second monomer or oligomer solution comprises two or more different monomers at least one of which is an ester of acrylic acid or of methacrylic acid.
Claim 33
Dependent Claim
17 words
The process of claims 29 or 30 wherein said first monomer is acrylic acid or methacrylic acid.
Claim 34
Dependent Claim
33 words
The process of claim 30 wherein said second monomer solution contains, in addition to at least one ester of acrylic or methacrylic acid, monomers chosen from acrylamide, acrylic acid, methacrylic acid, or methacrylamide.
Claim 35
Dependent Claim
20 words
The process of claim 30 wherein said second monomer solution contains two or more esters of acrylic or methacrylic acid.
Claim 36
Independent Claim
91 words
A method for reducing calcification of fixed animal biological tissue after implantation in an animal, wherein mitigation of calcification is maintained whether or not said tissue is subjected to flexing or stretching after implantation, comprising: covalently binding a monomer capable of further polymerization onto said biological tissue, and polymerizing one or more monomers or oligomers with said first monomer bound to said tissue prior to implantation to form an elastomeric polymer bound to said tissue in an amount effective to reduce calcification after implantation and increase the durability of the tissue.
Claim 37
Independent Claim
91 words
A method for reducing calcification of fixed animal biological tissue after implantation in an animal, wherein mitigation of calcification is maintained whether or not said tissue is subjected to flexing or stretching after implantation, comprising: covalently binding a monomer capable of further polymerization onto said biological tissue, and polymerizing one or more monomers or oligomers with said first monomer bound to said tissue prior to implantation to form an elastomeric polymer bound to said tissue in an amount effective to reduce calcification after implantation and increase the durability of the tissue.
Claim 38
Dependent Claim
44 words
Biological tissue having a reduced tendency toward calcification after implantation in an animal, including implantation in a position that subjects said tissue to stretching or flexing, said tissue having an elastomeric polymer incorporated therein according to the process of claim 1, 22 or 29.
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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) | 1991-09-13 | 1992-03-14 | 1992-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-13 | 1996-03-14 | 1996-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-13 | 2000-03-14 | 2000-09-13 | $7700.00 | Window Closed / Lapsed |