Patent ID: 7147806

Claim:
A method of making polymeric spheres having an average diameter of between 0.01 and 10.0 microns, comprising the steps of: a) providing a polymer solution of a polymeric material dissolved in a first fluid, said first fluid consisting of a supercritical, critical or near-critical fluid; and, b) depressurizing said polymer solution as said polymer solution exits one or more orifices in the presence of a low solubility fluid, said low solubility fluid having low volatility and said polymeric material in a concentration which exceeds said solubility of said polymeric material in said low solubility fluid, said polymeric material forming spheres having an average diameter between 0.01 and 10.0 microns and said first fluid removed during depressurization wherein said low solubility fluid is selected from the group of solvents consisting of PVA, PBS, liquid nitrogen, distilled water and an alcohol.