Patent US4677191A successfully refreshed from Google Patents.
US4677191A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Copolymer and method for producing the same
Assignee: Wada Pure Chemical Ind Ltd
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Filing: 1985-07-03
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Granted: 1987-06-30
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Expires: 2005-07-03
Abstract
Abstract A copolymer of lactic acid and glycolic acid which has a weight-average molecular weight of not less than about 5000 and a dispersity of about 1.5 to 2 is advantageously used as a biodegradable polymer for medical preparation.
Inventors
- 👤 Motoaki Tanaka
- 👤 Yasuaki Ogawa
- 👤 Tsutomu Miyagawa
- 👤 Toshio Watanabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:13
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/02; C08G63/06; A; A61; A61K; A61K9/00; A61K9/14; A61K9/16; A61K9/1605; A61K9/1629; A61K9/1641; A61K9/1647
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
30 words
A copolymer of lactic acid and glycolic acid free from catalyst, which has a weight-average molecular weight of about 5,000 to 30,000 and a dispersity of about 1.5 to 2.
Claim 2
Dependent Claim
30 words
A copolymer of lactic acid and glycolic acid free from catalyst, which has a weight-average molecular weight of about 5,000 to 30,000 and a dispersity of about 1.5 to 2.
Claim 3
Dependent Claim
31 words
A copopymer as claimed in claim 1, wherein the copolymer ratio is about 50 to 95 weight % of lactic acid and about 50 to 5 weight % of glycolic acid.
Claim 4
Dependent Claim
31 words
A copolymer as claimed in claim 1, wherein the copolymer ratio is about 60 to 95 weight % of lactic acid and about 40 to 5 weight % of glycolic acid.
Claim 5
Dependent Claim
31 words
A copolymer as claimed in claim 1, wherein the copolymer ratio is about 60 to 85 weight % of lactic acid and about 40 to 15 weight % of glycolic acid.
Claim 6
Dependent Claim
27 words
A copolymer as claimed in claim 1, wherein the copolymer ratio is about 75±2 mol % of lactic acid and about 25±2 mol % of glycolic acid.
Claim 7
Independent Claim
65 words
A method for producing a copolymer of lactic acid and glycolic acid, the copolymer having a weight-average molecular weight of not less than about 5,000 and a dispersity of about 1.5 to 2, which comprises subjecting lactic acid and glycolic acid or a low molecular polymer or copolymer of them to a polycondensation reaction under heating and reduced pressure in the absence of a catalyst.
Claim 8
Independent Claim
65 words
A method for producing a copolymer of lactic acid and glycolic acid, the copolymer having a weight-average molecular weight of not less than about 5,000 and a dispersity of about 1.5 to 2, which comprises subjecting lactic acid and glycolic acid or a low molecular polymer or copolymer of them to a polycondensation reaction under heating and reduced pressure in the absence of a catalyst.
Claim 9
Dependent Claim
55 words
A method as claimed in claim 6, wherein the low molecular copolymer of lactic acid and glycolic acid is produced by subjecting lactic acid and glycolic acid to undergo a condensation reaction in the absence of a catalyst and remove water, and the polycondensation reaction is carried out for about not less than 10 hours.
Claim 10
Dependent Claim
21 words
A method as claimed in claim 6, wherein the weight-average molecular weight of the resulting copolymer is about 5,000 to 30,000.
Claim 11
Dependent Claim
31 words
A method as climed in claim 6, wherein the copolymer ratio is about 50 to 95 weight % of lactic acid and about 50 to 5 weight % of glycolic acid.
Claim 12
Dependent Claim
31 words
A method as claimed in claim 6, wherein the copolymer ratio is about 60 to 95 weight % of lactic acid and about 40 to 5 weight % of glycolic acid.
Claim 13
Dependent Claim
31 words
A method as claimed in claim 6, wherein the copolymer ratio is about 60 to 85 weight % of lactic acid and about 40 to 15 weight % of glycolic acid.
Claim 14
Dependent Claim
27 words
A method as claimed in claim 6, wherein the copolymer ratio is about 75±2 mol % of lactic acid and about 25±2 mol % of glycolic acid.
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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) | 1990-06-29 | 1990-12-29 | 1991-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-29 | 1994-12-29 | 1995-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-29 | 1998-12-29 | 1999-06-30 | $7700.00 | Window Closed / Lapsed |