Formation of polymer particles with supercritical fluids: A review

Recent developments on particle formation from polymers using supercritical fluids have been reviewed with an emphasis on articles published during 2000–2003. First, a brief description of the basic operating principles of the various particle formation processes is presented. These include the rapid expansion of supercritical solutions (RESS), the gas antisolvent process (GAS), supercritical antisolvent process (SAS) and its various modifications, and the particles from gas-saturated solution (PGSS) processes. An account of the general review articles that have been published in previous years is then provided. The publications that have appeared over the past 4 years have been reviewed under two groupings, one involving the production of particles from pure polymers, and the other involving the production of polymer particles that contain active ingredients, especially those that pertain to pharmaceuticals. The majority of the efforts in the current supercritical particle formation technology is indeed on the production of polymer particles that are of pharmaceutical significance. In each grouping, the publications were further categorized according to the primary role played by the supercritical fluid in the process, namely whether it was used as a solvent, or as an antisolvent, or as a solute. This review is the first comprehensive review specifically focused on the formation of particles from polymers.