Formation of aqueous small droplet aerosols assisted by supercritical carbon dioxide

An aerosol with a high number density of particles with droplet sizes smaller than 3 mu m in diameter is produced by rapidly expanding an emulsion comprised of an aqueous solution and supercritical fluid CO2 at pressures from 1071 to 5000 psi at 35 degrees to 100 degrees C, After dilution with air, fine droplet aerosols of aqueous pharmaceuticals, such as rhDNase, are suitable for pulmonary drug delivery. Dehydration of the aqueous droplets yields fine-particle dry powders, potentially important in pharmaceutical processing and in the generation of fine particles of metal oxides by pyrolysis of metal nitrates or acetates, Thin films of metals or metal oxides can be formed by directing an aerosol containing coating precursors onto heated surfaces.