ABSTRACT
A supercritical fluid (SCF) process for particles production was first reported in Hannay and Hogarth (1879). In spite of this fact, it was only within the last four decades that supercritical fluid techniques were systematically investigated for micronization of pharmaceuticals, natural substances, pigments, (bio)polymers, superconductor precursors, among others. This chapter describes the SCF-based techniques that have been exploited to produce particles fine enough to be appropriately transported to the lungs. The application of SCFs for micronization of pharmaceuticals involves solutions containing solutes in very diluted concentrations. In order to design and optimize the processes for particle formation, it is necessary to have data on the solubility of compounds on the supercritical fluid media. When a supercritical solution expands rapidly through a nozzle device the fluid transits from supercritical to a two-phase state or to a low-pressure gas.
