US5041529A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation process for bioabsorbable polyester
Assignee: Mitsui Chemicals Inc
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Filing: 1989-10-27
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Granted: 1991-08-20
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Expires: 2009-10-27
Abstract
Abstract The invention relates to a process for the preparation of a bioabsorbable polyester comprising reacting said polyester under reduced pressure in the reaction system while maintaining said polyester in the molten state during the second half of the polymerization reaction or after completion of the reaction and obtaining said polyester which contain almost no residue of unreacted monomers and volatile ingredients of low molecular weight.
Inventors
- 👤 Hosei Shinoda
- 👤 Masami Ohtaguro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 04:11
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/88; C08G63/90; A; A61; A61K; A61K9/00; A61K9/20; A61K9/2004; A61K9/2022; A61K9/2031; A61K9/204; A61L; A61L17/00; A61L17/06; A61L17/10; A61L17/12; A61L31/00; A61L31/04; A61L31/06; C08G63/02; C08G63/06; C08G63/08
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
82 words
A process for the preparation of a bioabsorbable polyester having recurring structural units represented by the formula (I): ##STR3## wherein R 1 and R 2 are a hydrogen atom or a methyl group and can be the same or different, by the polymerization reaction of at least one of a glycolide and a lactide which comprises treating said polyester under reduced pressure in a reaction system while maintaining said polyester in a molten state during the second half of the polymerization reaction.
Claim 2
Dependent Claim
82 words
A process for the preparation of a bioabsorbable polyester having recurring structural units represented by the formula (I): ##STR3## wherein R 1 and R 2 are a hydrogen atom or a methyl group and can be the same or different, by the polymerization reaction of at least one of a glycolide and a lactide which comprises treating said polyester under reduced pressure in a reaction system while maintaining said polyester in a molten state during the second half of the polymerization reaction.
Claim 3
Dependent Claim
17 words
The process of claim 1 wherein the bioabsorbable polyester obtained contains 2% or less of residual monomer.
Claim 4
Dependent Claim
21 words
The process of claim 1 wherein the pressure in the reaction system is reduced to about 5 mm Hg or less.
Claim 5
Dependent Claim
27 words
The process of claim 1 wherein the pressure in the reaction system is reduced and an inert gas is passed through the polyester in the molten state.
Claim 6
Dependent Claim
34 words
The process of claim 1 wherein the pressure in the reaction system is reduced to about 5 mm Hg or less and the inert gas is passed through the polyester in the molten state.
Claim 7
Dependent Claim
57 words
The process of claim 1 wherein the bioabsorbable polyester is a glycolic-acid based polymer having recurring units represented by the formula(I) wherein a proportion of from 80 to 100% of R 1 and R 2 is a hydrogen atom and a proportion of from 0 to 20% of R 1 and R 2 is a methyl group.
Claim 8
Dependent Claim
24 words
The process of claim 6 wherein the bioabsorbable polyester is a a glycolic-acid based polymer having an inherent viscosity of 0.9 dl/g or more.
Claim 9
Dependent Claim
57 words
The process of claim 1 wherein the bioabsorbable polyester is a lactic-acid based polymer having recurring units represented by the formula(I) wherein a proportion of from 0 to 80% of R 1 and R 2 is a hydrogen atom and a proportion of from 20 to 100% of R 1 and R 2 is a methyl group.
Claim 10
Dependent Claim
23 words
The process of claim 8 wherein the bioabsorbable polyester is a lactic-acid based polyester having an inherent viscosity of 0.4 to 0.6 dl/g.
Claim 11
Dependent Claim
32 words
The process of claim 6 wherein the temperature in the second half of the reaction is maintained in the range of from the melting point of said polymer to about 250° C.
Claim 12
Dependent Claim
38 words
The process of claim 8 wherein the temperature in the second half of the reaction is maintained in the range of from the glass transition point of said polymer to about 200° C. above the glass transition point.
Claim 13
Dependent Claim
120 words
A process for the preparation of a bioabsorbable polyester having recurring structural units represented by the formula (I): ##STR4## wherein a proportion of from b 80 to 100% of R 1 and R 2 is a hydrogen atom and a proportion of from 0 to 20% of R 1 and R 2 is a methyl group, by the polymerization reaction of at least one of a glycolide and a lactide which comprises treating said polyester under reduced pressure of about 5 mm Hg or less in a reaction system while maintaining said polyester in a molten state in the range of from the melting point of said polymer to about 250° C. during the second half of the polymerization reaction.
Claim 14
Dependent Claim
120 words
A process for the preparation of a bioabsorbable polyester having recurring structural units represented by the formula (I): ##STR4## wherein a proportion of from b 80 to 100% of R 1 and R 2 is a hydrogen atom and a proportion of from 0 to 20% of R 1 and R 2 is a methyl group, by the polymerization reaction of at least one of a glycolide and a lactide which comprises treating said polyester under reduced pressure of about 5 mm Hg or less in a reaction system while maintaining said polyester in a molten state in the range of from the melting point of said polymer to about 250° C. during the second half of the polymerization reaction.
Claim 15
Dependent Claim
18 words
The process of claim 12 wherein an inert gas is passed through the polyester in the molten state.
Claim 16
Dependent Claim
125 words
A process for the preparation of a bioabsorbable polyester having recurring structural units represented by the formula (I): ##STR5## wherein a proportion of from 80 to 100% of R 1 and R 2 is a hydrogen atom and a proportion of from 20 to 100% of R 1 and R 2 is a methyl group, by the polymerization reaction of at least one of a glycolide and a lactide which comprises treating said polyester under reduced pressure of about 5 mm Hg or less in a reaction system while maintaining said polyester in a molten stage in the range of from the glass transition point of said polymer to about 200° C. above the glass transition point during the second half of the polymerization reaction.
Claim 17
Dependent Claim
125 words
A process for the preparation of a bioabsorbable polyester having recurring structural units represented by the formula (I): ##STR5## wherein a proportion of from 80 to 100% of R 1 and R 2 is a hydrogen atom and a proportion of from 20 to 100% of R 1 and R 2 is a methyl group, by the polymerization reaction of at least one of a glycolide and a lactide which comprises treating said polyester under reduced pressure of about 5 mm Hg or less in a reaction system while maintaining said polyester in a molten stage in the range of from the glass transition point of said polymer to about 200° C. above the glass transition point during the second half of the polymerization reaction.
Claim 18
Dependent Claim
18 words
The process of claim 14 wherein an inert gas is passed through the polyester in the molten state.
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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) | 1994-08-19 | 1995-02-18 | 1995-08-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-08-19 | 1999-02-18 | 1999-08-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-08-19 | 2003-02-18 | 2003-08-20 | $7700.00 | Window Closed / Lapsed |