Patent ID: 7449136

Claim:
A method of producing particles comprising the steps of: contacting a polymer, a wax and/or a lipid that is a solid at standard temperature and pressure with a supercritical fluid in the absence of any solvents to form a melt; contacting the melt with a solution comprising a solute dissolved in a solvent that is at least partially soluble in the supercritical fluid to form a mass comprising: a melt-rich fraction comprising the melt, a first portion of the supercritical fluid, and the solute, wherein the solute is in the form of solid particles that are dispersed in the melt; and a supercritical fluid-rich fraction comprising a second portion of the supercritical fluid and the solvent; and expanding the mass across a pressure drop into a collection vessel maintained above the boiling point of the solvent to evaporate the solvent and flash the supercritical fluid into a gas and thus form composite particles comprising the polymer, wax and/or lipid and the solute.