Process for the production of porous moulded articles containing alginate
The invention relates to a process for the production of alginate-containing porous or sponge-like moulded articles, and to the moulded articles obtainable thereby and their use.
1. A process for the production of freeze-dried porous molded articles comprising:
(a) mixing an aqueous alginate solution with at least one mineral acid until a pH of less than 6 is established,
(b) subsequently adding a component comprising calcium sulfate,
(c) pouring the resulting mixture into a mold and
(d) subsequently freeze-drying the resulting cross-linked alginate-mixture,
wherein the process excludes the addition of foam-stabilizing agents.
2. The process according to claim 1 , wherein the mineral acid is hydrochloric acid.
3. The process according to claim 1 , wherein the aqueous alginate solution is the aqueous solution of an alkali metal alginate.
4. The process according to claim 1 , wherein the component of (b), further comprises carboxymethylcelluose or a salt thereof.
5. The process according to claim 1 , wherein the component of (b) further comprises sodium carboxymethylcellulose.
6. The process according to claim 1 , further comprising after (a), and before (b), adding a complexing agent for calcium.
7. The process according to claim 6 , wherein the complexing agent is a carboxylate of an α-hydroxypolycarboxylic acid.
8. The process according to claim 7 , wherein the complexing agent is a citrate or malate of an α-hydroxypolycarboxylic acid.
9. The process according to claim 1 , further comprising before freeze-drying, adding at least one further component selected from the group consisting of: cosmetic or medical active ingredients; natural or synthetic hydrocolloid-forming polymers; and cosmetic or medical auxiliary substances or additives.
10. The process according to claim 9 , wherein the further component is at least one natural polysaccharide or a modified derivative thereof.
11. The process according to claim 9 , wherein the further component is hyaluronic acid or a salt thereof.
12. The process according to claim 9 , wherein the further component is urea or glycerin.
13. The process according to claim 9 , wherein the further component is squalane, jojoba oil or triglycerides of natural fatty acids.
14. The process according to claim 9 , wherein the further component is a vitamin.
15. The process according to claim 9 , wherein the further component is an agent for the treatment of skin diseases or an antibacterial agent.
16. The process according to claim 1 , wherein the addition of a salt of a polyvalent metal ion with a polydentate complexing anion is excluded.
17. The process according to claim 1 , further comprising cutting the freeze-dried molded article into layer form.
18. The process according to claim 1 , further comprising compressing the freeze-dried molded article into compressed form.
19. The process according to claim 18 , wherein the compressed molded article is in the form of an orally administrable agent.
20. The process according to claim 18 , wherein the compressed molded article is the form of an orally administrable satiating product.
21. The process according to claim 18 , wherein the compressed molded article is in the form of an orally administrable agent for the controlled release of an active ingredient.
22. The process according to claim 1 , wherein the pH value of the alginate solution, established by the mineral acid, is less than 5.
23. The process according to claim 1 , wherein the concentration of the alginate in the aqueous solution is less than 2% (w/w) and the pH value of the alginate solution, established by the mineral acid, is less than 5.
24. The process according to claim 1 , wherein the mixture is poured in a layer thickness of from 1 to 50 centimeters before freeze-drying.
25. The process according to claim 24 , wherein the resulting freeze-dried molded articles are cut into layers of 0.5 to 20 mm thickness.
26. The process according to claim 1 , wherein the concentration of the alginate in the aqueous solution is less than 2% (w/w) and the pH value of the alginate solution, established by the mineral acid, is less than 5, and wherein the resulting mixture is poured in a layer thickness of from 1 to 50 centimeters before freeze-drying.
27. A process for the production of freeze-dried porous molded articles comprising:
(a) mixing an aqueous alginate solution with a concentration of less than 2% (w/w) with at least one mineral acid until a pH of less than 5 is established,
(b) subsequently adding calcium sulfate,
(c) pouring the resulting mixture in a layer thickness of at least one centimeter up to 50 centimeter thickness into a mold,
(d) subsequently freeze-drying the resulting cross-linked alginate-mixture, and
(e) cutting the resulting freeze-dried molded articles into layers of 0.5 to 20 mm thickness,
wherein the process excludes the addition of foam-stabilizing agents.