US4024073A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrogel and production thereof
Assignee: Toray Industries Inc
•
Filing: 1975-02-21
•
Granted: 1977-05-17
•
Expires: 1995-02-21
Abstract
Abstract A novel and stable hydrogel contains a water-soluble polymer containing a chelating agent bound to the polymer chain, and a polyvalent metal ion cross-linking the polymer molecules through the chelating agent. The hydrogel is a carrier for timed release of drugs and medicaments.
Inventors
- 👤 Hirohiko Shimizu
- 👤 Hitoshi Ozawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:42
CPC Classifications
A; A61; A61K; A61K47/00; A61K47/30; A61K47/36; A61K47/34; A61K47/38; A61K9/00; A61K9/0012; A61K9/0019; B; B01; B01J; B01J13/00; B01J13/0052; B01J13/0065; C; C08; C08B; C08B15/00; C08B15/10; C08B31/00; C08B31/003; C08B33/00; C08B37/00; C08H; C08H1/00; C08L; C08L77/00; C08L77/04
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
56 words
A hydrogel comprising a water-soluble polymer selected from the group consisting of dextrans, starches and celluloses containing a chelating agent selected from the group consisting of cystine and lysine bound to the polymer chain and a polyvalent metal ion, in which the polymers are cross-linked through chelation between the chelating agents by said polyvalent metal ion.
Claim 2
Dependent Claim
56 words
A hydrogel comprising a water-soluble polymer selected from the group consisting of dextrans, starches and celluloses containing a chelating agent selected from the group consisting of cystine and lysine bound to the polymer chain and a polyvalent metal ion, in which the polymers are cross-linked through chelation between the chelating agents by said polyvalent metal ion.
Claim 3
Dependent Claim
28 words
A hydrogel of claim 1 in which the said water-soluble polymer contains about 1 to 100 of said chelating agent per one hundred monomer units in the polymer.
Claim 4
Dependent Claim
27 words
A hydrogel of claim 1 in which the polyvalent metal ion is selected from the group consisting of the alkali earth metals, transition metals, and aluminium ions.
Claim 5
Independent Claim
74 words
A method for preparing a hydrogel which comprises contacting an aqueous solution of a water-soluble polymer selected from the group consisting of dextrans, starches and celluloses containing a chelating agent selected from the group consisting of cystine and lysine bound to a polymer chain, in which the concentration of the polymer is about 1 to 70% by weight, with a polyvalent metal ion at a temperature from about room temperature to about 100° C.
Claim 6
Independent Claim
74 words
A method for preparing a hydrogel which comprises contacting an aqueous solution of a water-soluble polymer selected from the group consisting of dextrans, starches and celluloses containing a chelating agent selected from the group consisting of cystine and lysine bound to a polymer chain, in which the concentration of the polymer is about 1 to 70% by weight, with a polyvalent metal ion at a temperature from about room temperature to about 100° C.
Claim 7
Dependent Claim
13 words
A method of claim 4 in which gelation is carried out by dialysis.
Claim 8
Dependent Claim
29 words
A hydrogel comprising carboxy methyl amylose bound to cystine and a zinc ion, wherein said carboxy methyl amylose is cross-linked through chelation between said cystine and said zinc ion.
Claim 9
Dependent Claim
29 words
A hydrogel comprising carboxy methyl amylose bound to cystine and a zinc ion, wherein said carboxy methyl amylose is cross-linked through chelation between said cystine and said zinc ion.
Claim 10
Dependent Claim
45 words
A hydrogel comprising a water-soluble starch containing a chelating agent selected from the group consisting of cystine and lysine bound to said starch and a polyvalent metal ion, in which said starch is cross-linked through chelation between the chelating agents by said polyvalent metal ion.
Claim 11
Dependent Claim
45 words
A hydrogel comprising a water-soluble starch containing a chelating agent selected from the group consisting of cystine and lysine bound to said starch and a polyvalent metal ion, in which said starch is cross-linked through chelation between the chelating agents by said polyvalent metal ion.
References Cited (Backward Citations)
US3378070A
Cited
US3804174A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-16 | 1980-11-15 | 1981-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-16 | 1984-11-15 | 1985-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-16 | 1988-11-15 | 1989-05-17 | $7700.00 | Window Closed / Lapsed |