A new supercritical fluid (SCF) technique was developed for the preparation of fine particles for Pulmonary Drug Delivery (PDD).The drug solution was sprayed into a continuous feed of high pressure carbon dioxide, fine particles precipitated as a result of expansion of the droplets and removal of water by the CO2-organic solvent mixture.Model insulin was precipitated using this new process as micron-sized particles.Stabilized formulation of inhaled dry powder can be obtained and its bioactivity is preserved as before processing.