US4814437A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for preparation of sulfated polysaccharides by treating the polysaccharide with a reducing agent before sulfation
Assignee: Pfizer Health AB
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Filing: 1988-02-25
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Granted: 1989-03-21
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Expires: 2008-02-25
Abstract
Abstract A new method for preparation of sulfated polysaccharides by means of pyridine-chlorosulfonic acid reagents. The polysaccharide is before sulfation treated with a reducing agent, e.g. sodium borohydride.
Inventors
- 👤 Anthony N. de Belder
- 👤 Leif G. Ahrgren
- 👤 Tomas Malson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:13
CPC Classifications
C; C08; C08B; C08B31/00; C08B31/02; C08B31/06; C08B31/063; C08B37/00; C08B37/0006; C08B37/0009; C08B37/0021; C08B37/0057; C08B5/00; C08B5/14
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
37 words
A method for producing sulfated polysaccharides by reacting the polysaccharide with a pyridine-chlorosulfonic acid reagent, wherein the polysaccharide before the sulfation reaction is treated with an agent which reduces most of the reducing end-groups of the polysaccharides.
Claim 2
Independent Claim
37 words
A method for producing sulfated polysaccharides by reacting the polysaccharide with a pyridine-chlorosulfonic acid reagent, wherein the polysaccharide before the sulfation reaction is treated with an agent which reduces most of the reducing end-groups of the polysaccharides.
Claim 3
Dependent Claim
12 words
A method according to claim 1 wherein the reducing agent is borohydride.
Claim 4
Dependent Claim
15 words
A method according to claim 1 wherein the reducing agent is sodium or potassium borohydride.
Claim 5
Dependent Claim
21 words
A method according to claim 1 wherein the polysaccharide is dextan, starch, cellulose or a derivative of these, or a glycosaminoglycan.
Claim 6
Dependent Claim
21 words
A method according to claim 2 wherein the polysaccharide is dextran, starch, cellulose or a derivative of these, or a glycosaminoglycan.
Claim 7
Dependent Claim
21 words
A method according to claim 3 wherein the polysaccharide is dextran, starch, cellulose or a derivative of these, or a clycosaminoglycan.
Claim 8
Dependent Claim
12 words
A method according to claim 1 wherein the polysaccharide is hyaluronic acid.
Claim 9
Dependent Claim
12 words
A method according to claim 2 wherein the polysaccharide is hyaluronic acid.
Claim 10
Dependent Claim
12 words
A method according to claim 3 wherein the polysaccharide is hyaluronic acid.
Claim 11
Dependent Claim
12 words
A method according to claim 4 wherein the polysaccharide is hyaluronic acid.
Claim 12
Dependent Claim
12 words
A method according to claim 5 wherein the polysaccharide is hyaluronic acid.
Claim 13
Dependent Claim
12 words
A method according to claim 6 wherein the polysaccharide is hyaluronic acid.
References Cited (Backward Citations)
US3947352A
Cited
US4740594A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-03-20 | 1992-09-19 | 1993-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-20 | 1996-09-19 | 1997-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-20 | 2000-09-19 | 2001-03-21 | $7700.00 | Window Closed / Lapsed |