Preservation of bioactive materials by freeze dried foam
This invention provides methods and compositions to preserve bioactive materials in a dried foam matrix. Methods provide non-boiling foam generation and penetration of preservative agents at temperatures near the phase transition temperature of the membranes.
1. A method for preparing a dry foam composition comprising a bioactive material, which method comprises:
preparing a formulation comprising in a solvent: the bioactive material, a foaming agent, and a polyol or polymer;
expanding the formulation into a foam; and,
stabilizing or drying the foam by evaporating or sublimating the solvent from the foam;
thereby preparing a dry foam composition.
2. The method of claim 1 , wherein the bioactive material is selected from the group consisting of peptides, proteins, nucleic acids, antibodies, vaccines, bacteria, viruses, liposomes, platelets, and cell suspensions.
3. The method of claim 2 , wherein the viruses are live viruses selected from the group consisting of influenza virus, parainfluenza virus, AAV, adenovirus, respiratory syncytial virus, herpes simplex virus, cytomegalovirus, SARS virus, corona virus family members, human metapneumovirus, and Epstein-Barr virus.
4. The method of claim 1 , wherein the foaming agent comprises a gas in solution in the formulation, a high vapor pressure solvent, a carbonate, an active metal, or a suspension of gas bubbles.
5. The method of claim 1 , wherein the polyol is present in an amount ranging from about 20 weight percent to about 45 weight percent.
6. The method of claim 1 , wherein the polyol comprises sucrose, trehalose, sorbose, melezitose, sorbitol, stachyose, raffinose, fructose, mannose, maltose, lactose, arabinose, xylose, ribose, rhamnose, galactose, glucose, mannitol, xylitol, erythritol, threitol, sorbitol, glycerol, or L-gluconate.
7. The method of claim 1 , wherein the polymer is present in an amount ranging from about 1 weight percent to about 10 weight percent.
8. The method of claim 1 , wherein the polymer comprises hydrolyzed gelatin, unhydrolyzed gelatin, collagen, chondroitin sulfate, water soluble polymers, polyvinyl pyrrolidone, a sialated polysaccharide, actin, myosin, microtubules, dynein, kinetin, or human serum albumin.
9. The method of claim 1 , wherein expanding into a foam comprises, degassing the formulation, boiling the formulation, forming a gas by chemical reaction, forming bubbles by electrolysis, expanding bubbles suspended in the formulation, or injection of bubbles into the formulation.
10. The method of claim 1 , wherein the formulation further comprises a surfactant or a buffer.
11. The method of claim 1 , wherein the bioactive material comprises a lipid membrane, and wherein the method further comprises cooling the formulation to a phase transition temperature of the lipid membrane.
12. The method of claim 11 , further comprising holding the formulation at the phase transition temperature for from about 10 minutes to about 60 minutes.
13. The method of claim 1 , further comprising increasing the temperature of the formulation to a drying temperature that is less than or about the glass transition temperature of the dry foam.
14. The method of claim 1 , further comprising grinding the dry foam to a powder comprising an average particle size from about 0.1 um to about 100 um.
15. The method of claim 14 , wherein the a powder comprises an average particle size from about 50 um to about 100 um.
16. The method of claim 1 , further comprising administering the dry foam composition to a mammal as a reconstituted liquid or as a ground powder.
17. The method of claim 16 , wherein administering comprises delivering the composition to the mammal by intravenous, intramuscular, intraperitoneal, intracerebrospinal, subcutaneous, intra-articular, intrasynovial, intrathecal, oral, topical, intranasal, or pulmonary routes.
18. The method of claim 1 , further comprising secondary drying the foam at a temperature from about 10° C. to about 70° C.
19. The method of claim 1 , wherein said preparing the formulation comprises providing sufficient polyol so that a glass is formed upon said drying step.
20. The method of claim 1 , wherein the expanding is other than by boiling.
21. The method of claim 1 , wherein the foaming agent is other than the solvent.
22. The method of claim 1 , wherein said expansion is by action of the foaming agent.