Lyophilization method and apparatus for producing particles
First Claim
11. An apparatus for producing particles comprising:
- a solution source supplying a solution comprising a solvent and a solute, and a fluid source supplying a compressed fluid;
a mixer in fluid communication with the sources for mixing the solution and the compressed fluid together to form a mixture, and for maintaining the mixture at a first pressure sufficiently high so as to maintain the compressed fluid in a compressed state;
an expansion assembly in fluid communication with the mixer for spraying the mixture across a pressure drop to form mixture droplets, the mixture droplets comprising the solute and frozen solvent; and
a freeze-dry apparatus that is in communication with the expansion assembly for subliming the frozen solvent, and thereby removing the frozen solvent from the solute, whereby solute particles are produced that are generally free of the solvent.
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Accused Products
Abstract
A method and apparatus for producing particles, the apparatus includes a solution source that supplies a solution, and a fluid source that supplies a fluid. The solution includes a solvent and a solute. A mixer receives the solution and the fluid from the sources, and mixes the solution and the fluid together to form a mixture. The mixture is supplied from the mixer to an expansion assembly at first pressure. The expansion assembly sprays and expands the mixture substantially simultaneously to form frozen droplets, and preferably to form a low-density powder of frozen droplets. A freeze-dry apparatus sublimes the solvent from the particles. A high mass-transfer rate and a uniform open-structure of the powder bed enhances the freeze-drying process. Solid particles having a controlled size distribution are obtained. The particles preferably have a hollow or porous morphology suitable for differing drug delivery applications to include aerosol formulations.
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Citations
27 Claims
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11. An apparatus for producing particles comprising:
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a solution source supplying a solution comprising a solvent and a solute, and a fluid source supplying a compressed fluid;
a mixer in fluid communication with the sources for mixing the solution and the compressed fluid together to form a mixture, and for maintaining the mixture at a first pressure sufficiently high so as to maintain the compressed fluid in a compressed state;
an expansion assembly in fluid communication with the mixer for spraying the mixture across a pressure drop to form mixture droplets, the mixture droplets comprising the solute and frozen solvent; and
a freeze-dry apparatus that is in communication with the expansion assembly for subliming the frozen solvent, and thereby removing the frozen solvent from the solute, whereby solute particles are produced that are generally free of the solvent. - View Dependent Claims (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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21-1. The apparatus as defined in claim 11 further comprising a thermostat, and wherein the expansion assembly comprises an expansion vessel having an inner surface defining an expansion chamber, and the thermostat is operable to control a temperature in the expansion chamber to be below the solution freezing temperature.
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27. An apparatus for producing particles comprising:
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means for mixing a solution and a compressed fluid together to form a mixture, the solution comprising a solute dissolved in a solvent;
means for flowing the mixture across a pressure drop into an expansion chamber, whereby the mixture forms droplets and at least a portion of the compressed fluid expands from a compressed state to a relatively uncompressed state, thereby reducing a temperature of the droplets to be below a freezing point of the solution; and
means for freeze-drying the frozen droplets of solution to sublime the frozen solvent and form generally solvent free solute particles.
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Specification