EP0459733A2
Expired / Lapsed
EP
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Alginate gels
Assignee: Pronova Biopolymer AS
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Filing: 1991-05-24
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Granted: —
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Expires: 2011-05-24
Abstract
Abstract Superswelling cross-linked alginate gels which can swell strongly with a controllable swelling time in water, aqueous solutions of salts, proteins or the like. Process for the preparation of the alginate gels comprises the transferring of a water soluble alginate to an alginate gel, followed by a cross-linking reaction, reintroduction of non-gelling ions and drying the thus prepared gel.
Inventors
- 👤 Gudmund Skjak-Braek
- 👤 Moe Storker
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 21:48
CPC Classifications
C; C08; C08L; C08L5/00; C08L5/04; A; A61; A61K; A61K47/00; A61K47/30; A61K47/36; A61K9/00; A61K9/14; A61K9/16; A61K9/1605; A61K9/1629; A61K9/1652; A61L; A61L15/00; A61L15/16; A61L15/42; A61L15/60; C08B; C08B37/00; C08B37/006; C08B37/0084
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
37 words
Crosslinked alkali metal and ammonium alginate gels characterized in a swellability of 10-300 times its volum in water or 2-70 times its volume in physiological saline solution and in that they keep their original form after swelling.
Claim 2
Dependent Claim
29 words
Alginate gels according to claim 1 characterized in that they have an ability to swell of 50-200 times their volume in water, especially 100 times their volume in water.
Claim 3
Dependent Claim
94 words
Process for the preparation of cross-linked alkalie metal or ammonium alginate gels characterized in - adding an aqueous solution of an alginate to an aqueous saline solution comprising at least one polyvalent gelforming cation; - replacing the aqueous solvent with an organic solvent or mixture of solvents wherein a crosslinking agent is soluble; - reacting the alginate gel suspended in the organic solvent with a cross-linking agent; - removing the remaining cross-linking agent by washing with an organic solvent and/or water; - replacing gelforming cations with non-gelforming monovalent cations in aqueous phase; - drying.
Claim 4
Dependent Claim
50 words
Process according to claim 3 characterized in that the alginate gel is dryed by replacing the aqueous phase with an organic solvent or mixture of sol vents, especially a solvent or mixture of solvents which can be mixed with water, followed by drying in air or with an inert gas.
Claim 5
Dependent Claim
161 words
Process according to claim 3 characterized in - adding a 0.8-5% w/v aqueous solution of an alginate to an aqueous salt solution comprising at least one polyvalent gelforming cation in a concentration of 10mM-1M, preferably in the presence of a nongelling salt; - replacing the aqueous solvent with an organic solvent or mixture of solvents wherein a crosslinking agent is soluble; - reacting the alginate gel in the organic solvent with 0.1-4M of a cross-linking agent, preferably in the presence of 0.5-15mM CaCl₂ and 10-500mM NaOH for 1-8 hours; - removing the remaining cross-linking agent by washing with an organic solvent and/or water; - replacing the gelforming cations with an excess of non-gelforming monovalent cations in aqueous solution; - drying by replacing the aqueous solvent with an organic solvent, especially a solvent which is mixable with water, such as aceton, methanol, ethanol, isopropylalcohol, followed by drying of the alginate gel with air or an inert gas, preferably in a fluidized bed.
Claim 6
Dependent Claim
132 words
Process according to claim 3 characterized in - adding of an aqueous solution of a sodium alginate, 1-3% w/v, to an aqueous solution of CaCl₂, 0.1-0.5M, with addition of NaCl, 0.1-2M; - replacing the aqueous solvent with ethanol; - reacting the alginate gel suspended in the organic solvent, representing three volume parts, with 0.5-2 volume parts 100 % epichlorohydrin, in the presence of 1 volume part 0.1M CaCl₂ and 1 volume part 10-500mM NaOH at roomtemperature for 1-8 hours; - removing the remaining cross-linking agent by washing with ethanol; - replacing the Ca ions with Na ions by adding to 51 20-500mM sodium EDTA in an aqueous phase; - drying by adding ethanol in totally 6 times the gelvolume in several sequences with equilibration between each time and drying at room temperature.
References Cited (Backward Citations)
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