Patent ID: 6931888

Claim:
An apparatus for producing particles comprising: a solution source for supplying a solution comprising a solvent and a solute; a supercritical fluid source for supplying a supercritical fluid; a mixer in fluid communication with the solution source and the supercritical fluid source for mixing the solution and the supercritical fluid together to form a mixture, and for maintaining the mixture at a first pressure sufficiently high so as to maintain the supercritical fluid in a supercritical state; an expansion assembly comprising an expansion vessel having an inner surface defining an expansion chamber that is 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; a thermostat that is operable to control a temperature in the expansion chamber to be below the solution freezing temperature; 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.