US4683288A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polymer and its production
Assignee: Takeda Pharmaceutical Co Ltd
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Filing: 1985-07-03
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Granted: 1987-07-28
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Expires: 2005-07-03
Abstract
Abstract A polymer or copolymer of lactic acid and/or glycolic acid which has a weight-average molecular weight of not less than about 5,000 and a dispersity of about 1.5 to 2 is advantageously used as a biodegradable polymer or copolymer 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 10:28
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
70 words
In a method for producing a polymer or copolymer of lactic acid and/or glycolic acid by subjecting lactic acid and/or glycolic acid to a polycondensation reaction, an improvement which comprises employing a solid inorganic acid catalyst as a polycondensation catalyst, wherein the solid inorganic acid catalyst is one selected from the group consisting of acid clay, activated clay, bentonite, kaolin, talc, aluminum silicate, magnesium silicate, alumina bolia and silicic acid.
Claim 2
Dependent Claim
70 words
In a method for producing a polymer or copolymer of lactic acid and/or glycolic acid by subjecting lactic acid and/or glycolic acid to a polycondensation reaction, an improvement which comprises employing a solid inorganic acid catalyst as a polycondensation catalyst, wherein the solid inorganic acid catalyst is one selected from the group consisting of acid clay, activated clay, bentonite, kaolin, talc, aluminum silicate, magnesium silicate, alumina bolia and silicic acid.
Claim 3
Dependent Claim
33 words
A method as claimed in claim 1, wherein the weight-average molecular weight of the polymer or copolymer is about not less than 5,000 and a dispersity of it is about 1.5 to 2.
Claim 4
Dependent Claim
32 words
A method as claimed in claim 1, wherein the weight-average molecular weight of the polymer or copolymer is about 5,000 to 30,000 and a dispersity of it is about 1.5 to 2.
Claim 5
Dependent Claim
13 words
A method in claim 1, wherein the polymer consists of lactic acid unit.
Claim 6
Dependent Claim
18 words
A method as claimed in claim 1, wherein the copolymer consists of lactic acid and glycolic acid units.
Claim 7
Dependent Claim
31 words
A method as claimed in claim 5, wherein the copolymer ratio is about 50 to 95 weight % of lactic acid and about 50 to 5 weight % of glycolic acid.
Claim 8
Dependent Claim
31 words
A method as claimed in claim 5, wherein the copolymer ratio is about 60 to 95 weight % of lactic acid and about 40 to 5 weight % of glycolic acid.
Claim 9
Dependent Claim
31 words
A method as claimed in claim 5, wherein the copolymer ratio is about 60 to 85 weight % of lactic acid and about 40 to 15 weight % of glycolic acid.
Claim 10
Dependent Claim
27 words
A method as claimed in claim 5, wherein the copolymer ratio is about 75±2 mol % of lactic acid and about 25±2 mol % of glycolic acid.
Claim 11
Dependent Claim
30 words
A method as claimed in claim 1, wherein the solid inorganic acid catalyst is one selected from the group consisting of acid clay, activated clay, kaolin, bentonite and aluminium silicate.
Claim 12
Dependent Claim
16 words
A method as claimed in claim 1, wherein the solid inorganic acid catalyst is acid clay.
Claim 13
Dependent Claim
16 words
A method as claimed in claim 1, wherein the solid inorganic acid catalyst is activated clay.
Claim 14
Dependent Claim
16 words
A method as claimed in claim 1, wherein the solid inorganic acid catalyst is aluminium silicate.
References Cited (Backward Citations)
US2362511A
Cited
US2703316A
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US3531561A
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US3468853A
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US3636956A
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US3839297A
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US4137921A
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US4273920A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-07-27 | 1991-01-26 | 1991-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-07-27 | 1995-01-26 | 1995-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-07-27 | 1999-01-26 | 1999-07-28 | $7700.00 | Window Closed / Lapsed |