Method for rehydrating polysaccharide particles

Patent metadata

Field	Value
Publication number	US-9561248-B2
Application number	US-201414324889-A
Country	US
Kind code	B2
Filing date	Jul 7, 2014
Priority date	Apr 24, 2008
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

Tissue and other body structures may be protected using a hydrated composition made from free-flowing substantially collagen-free rehydratable polysaccharide particles and rehydratable polysaccharide sponges. Rehydration of the particles without clumping may be carried out be dispersing the particles in a biocompatible water-miscible polar dispersant such as ethanol and combining the dispersion with sufficient aqueous solvent for the particles to convert them to a cohesive hydrogel. The hydrated composition may assist in returning an injured, inflamed or surgically repaired surface to a normal state, e.g., through one or more healing mechanisms such as modulation of an inflammatory response, phagocytosis, mucosal remodeling, reciliation or other full or partial restoration of normal function.

First claim

We claim:

1. A method for converting a dry powdered composition to a gel, which method comprises:
a) dispersing free-flowing polysaccharide particles in a biocompatible water-miscible polar dispersant that is a sufficiently poor solvent for the particles so that the mixture of particles and dispersant will not form a true solution, and
b) combining the resulting dispersion with sufficient aqueous solvent for the particles to convert them to a cohesive hydrogel,
wherein the water-miscible polar dispersant comprises water, ethanol, isopropanol or acetone.

2. A method according to claim 1 wherein the water-miscible polar dispersant is water and the aqueous solvent for the particles is acidified water.

3. A method according to claim 1 wherein the water-miscible polar dispersant comprises ethanol.

4. A method according to claim 1 wherein the water-miscible polar dispersant comprises isopropanol or acetone.

5. A method according to claim 1 wherein the polysaccharide particles have been crosslinked.

6. A method according to claim 1 wherein the polysaccharide particles have been crosslinked using a separate crosslinking agent.

7. A method according to claim 1 wherein the polysaccharide particles are uncrosslinked.

8. A method according to claim 1 wherein the polysaccharide particles are substantially collagen-free.

9. A method according to claim 1 wherein the polysaccharide particles are substantially a single polysaccharide.

10. A method according to claim 1 wherein the polysaccharide particles are a blend of two or more polysaccharides.

11. A method according to claim 1 wherein the polysaccharide comprises cellulose, chitosan, agar, alginate, carrageenan, chitin, chondroitin sulfate, dextran, galactomannan, glycogen, hyaluronic acid, starch or mixture thereof.

12. A method according to claim 1 wherein the polysaccharide comprises an oxidized polysaccharide or salt.

13. A method according to claim 1 wherein the polysaccharide comprises carboxymethylcellulose.

14. A method according to claim 1 wherein the polysaccharide is substantially only carboxymethylcellulose.

15. A method according to claim 1 wherein the polysaccharide comprises chitosan.

16. A method according to claim 15 wherein the chitosan is unmodified.

17. A method according to claim 1 wherein the polysaccharide comprises a mixture of chitosan and another polysaccharide.

18. A method according to claim 1 wherein the polysaccharide comprises a mixture of carboxymethylcellulose and chitosan.

19. A method according to claim 1 comprising forming the cohesive hydrogel without visible clumps of unhydrated polysaccharide.

20. A method according to claim 1 further comprising injecting or spraying a layer of the cohesive hydrogel onto mucosal tissue.

21. A method according to claim 1 further comprising injecting or spraying the cohesive hydrogel into an opening, recess, passageway or joint in a limb.

22. A method according to claim 1 further comprising injecting or spraying the cohesive hydrogel into an opening, recess, passageway or joint in a spinal column.

23. A method for converting a dry powdered composition to a gel, which method comprises:
a) dispersing free-flowing polysaccharide particles in a biocompatible water-miscible polar dispersant, and
b) combining the resulting dispersion with sufficient aqueous solvent for the particles to convert them to a cohesive hydrogel,

wherein the polysaccharide particles have been dehydrothermally crosslinked.

Assignees

• Medtronic Inc

Inventors

• Myntti Matthew F
• Oliver Dana A
• Vaccaro Brian J

Classifications

• A61L2/087

  Particle radiation, e.g. electron-beam, alpha or beta radiation · CPC title

• A61L2103/05

  Living organisms or biological materials · CPC title

• A61K9/0085

  Brain, e.g. brain implants; Spinal cord · CPC title

• A61K47/38

  Cellulose; Derivatives thereof · CPC title

• A61K31/718

  Starch or degraded starch, e.g. amylose, amylopectin · CPC title