US4868274A
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Polyanhydride from carboxy aryloxy alkanoic acid
Assignee: Hoechst Celanese Chemical Co
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Filing: 1988-05-23
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Granted: 1989-09-19
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Expires: 2008-05-23
Abstract
Abstract There are provided novel homopolyanhydrides of carboxyaryloxyalkanoic acids, e.g. p-carboxyphenoxyacetic acid or 6-(p-carboxyphenoxy)hexanoic acid, capable of being formed into shaped articles. The homopolyanhydrides may be prepared by heating under reflux a solution of the acid monomer in acetic anhydride to form a mixed anhydride of the acid monomer and acetic acid and melt polycondensing the prepolymer by heating it under vacuum in an inert atmosphere. Due to their property of hydrolytic cleavage at predictable rates, the homopolyanhydrides are suitable as polymer matrices providing for the controlled release of an agent such as a drug.
Inventors
- 👤 Balaram Gupta
- 👤 Gordon W. Calundann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 00:07
CPC Classifications
C; C08; C08F; C08F20/00; C08F20/02; C08F20/08; C08G; C08G67/00; C08G67/04
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
15 words
A homopolyanhydride of a carboxyaryloxyalkanoic acid, which is capable of being formed into shaped articles.
Claim 2
Dependent Claim
15 words
A homopolyanhydride of a carboxyaryloxyalkanoic acid, which is capable of being formed into shaped articles.
Claim 3
Dependent Claim
31 words
The homopolyanhydride of claim 1 having the formula: CH.sub.3 CO--O--[CO--Ar'--O--(CH.sub.2).sub.x --CO--O].sub.n' --COCH.sub.3 wherein Ar' is a divalent arylene group, x is 1 to 10 and n' is at least about 80.
Claim 4
Dependent Claim
23 words
The homopolyanhydride of claim 2 wherein Ar' is 1,4-phenylene or 2,6-naphthylene, x is 1 to 5 and n' is about 90 to 200.
Claim 5
Dependent Claim
9 words
The homopolyanhydride of claim 3 wherein Ar' is 1,4-phenylene.
Claim 6
Dependent Claim
9 words
The homopolyanhydride of claim 4 which is poly(p-carboxyphenoxyacetic acid).
Claim 7
Dependent Claim
9 words
The homopolyanhydride of claim 4 which is poly[6-(p-carboxyphenoxy)hexanoic acid].
Claim 8
Dependent Claim
14 words
A prepolymer which is a mixed anhydride of a carboxyaryloxyalkanoic acid and acetic acid..
Claim 9
Dependent Claim
14 words
A prepolymer which is a mixed anhydride of a carboxyaryloxyalkanoic acid and acetic acid..
Claim 10
Dependent Claim
31 words
The prepolymer of claim 7 having the formula: CH.sub.3 CO--O--[CO--Ar'--O--(CH.sub.2).sub.x --CO--O].sub.n --COCH.sub.3 wherein Ar' is a divalent arylene group, x is 1 to 10 and n is 1 to about 10.
Claim 11
Dependent Claim
17 words
The prepolymer of claim 8 wherein Ar' is 1,4-phenylene or 2,6-naphthylene and x is 1 to 5.
Claim 12
Dependent Claim
9 words
The prepolymer of claim 9 wherein Ar' is 1,4-phenylene.
Claim 13
Dependent Claim
16 words
The prepolymer of claim 10 which is a mixed anhydride of p-carboxyphenoxyacetic acid and acetic acid.
Claim 14
Dependent Claim
16 words
The prepolymer of claim 10 which is a mixed anhydride of 6-(p-carboxyphenoxy)hexanoic acid and acetic acid.
Claim 15
Dependent Claim
67 words
A process of preparing a homopolyanhydride comprising dissolving a carboxyaryloxyalkanoic acid in excess acetic anhydride, heating the solution under refluxing condition for a period sufficient to form a mixed anhydride prepolymer, separating the prepolymer from the reaction solution, and melt polycondensing said prepolymer by heating it in an inert atmosphere under vacuum while drawing off acetic anhydride formed during the reaction, until the desired homopolyanhydride is obtained.
Claim 16
Dependent Claim
67 words
A process of preparing a homopolyanhydride comprising dissolving a carboxyaryloxyalkanoic acid in excess acetic anhydride, heating the solution under refluxing condition for a period sufficient to form a mixed anhydride prepolymer, separating the prepolymer from the reaction solution, and melt polycondensing said prepolymer by heating it in an inert atmosphere under vacuum while drawing off acetic anhydride formed during the reaction, until the desired homopolyanhydride is obtained.
Claim 17
Dependent Claim
12 words
The process of claim 13 wherein said carboxyaryloxyalkanoic acid is p-carboxyphenoxyacetic acid.
Claim 18
Dependent Claim
12 words
The process of claim 14 wherein said carboxyaryloxyalkanoic acid is 6-(p-carboxyphenoxy)hexanoic acid.
References Cited (Backward Citations)
US4546152A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-09-18 | 1993-03-20 | 1993-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-18 | 1997-03-20 | 1997-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-18 | 2001-03-20 | 2001-09-19 | $7700.00 | Window Closed / Lapsed |