Preservation of bioactive materials by freeze dried foam
AssigneeMedImmune, LLC
InventorsReinhard Vehring, Yi Ao
Life of this patent
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Abstract
This invention provides methods, systems 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. Bioactive materials can be preserved with high initial viability in a freeze-foam process employing low temperature secondary drying.
Claims22
A method for preparing a stable dry foam composition comprising a bioactive material, which method comprises:
- preparing a formulation comprising the bioactive material, and a polyol or polymer, in a solvent;
- expanding the formulation into a foam which comprises an aspect ratio of 10 or more;
- freezing the foam;
- primary drying the frozen foam by sublimation at a foam temperature of 0° C. or less;
- and,
- secondary drying the foam in an environment with a temperature of 25° C. or less for a time sufficient to reduce the foam to a residual moisture of 10 percent or less.
A method for preparing a stable dry foam composition comprising a bioactive material, which method comprises:
- preparing a formulation comprising the bioactive material, and a polyol or polymer, in a solvent;
- expanding the formulation into a foam which comprises an aspect ratio of 10 or more;
- freezing the foam;
- primary drying the foam by sublimation at a temperature wherein the foam is frozen or remains below the glass transition temperature of the foam;
- and,
- secondary drying the foam in an environment of 25° C. or less for a time sufficient to reduce the foam to a 10 percent residual moisture or less.
A system for preparing a stable dry foam composition comprising a bioactive material, which system comprises:
- an environment control chamber comprising control of internal temperature and internal pressure;
- and,
- a foam within the chamber, which foam comprises the bioactive material, and a polyol or polymer, in a solvent;
- wherein, the foam has a thickness of 2 mm or less or an aspect ratio of 10 or more;
- and,
- wherein the system is configured to dry the foam to a 10 percent residual moisture or less, at a temperature of 25° C. or less, over a time period of 2 days or less.
A dry foam composition comprising:
- a bacteria or virus in a dry foam matrix comprising a 10 percent residual moisture or less;
- wherein the matrix comprises a polyol or polymer;
- and,
- wherein the dry foam was prepared from a liquid formulation of the bacteria or virus with less than a 0.5 log10 loss of viability.
Dependencies are inferred from the claim text.