Micronization by supercitical antisolvent precipitation processes

Abstract

In the last decade, the application of microparticles, nanoparticles and composite microparticles involved several industrial fields. Conventional micronization techniques, such as jet milling, spray drying, liquid antisolvent precipitation and solvent evaporation are sometimes not suitable, since the produced particles are irregular, with broad size distribution, could be degraded due to mechanical or thermal stresses and polluted with organic solvents or other toxic substances. In this context, supercritical fluids (SCFs) based techniques have been proposed as an alternative to traditional processes thanks to the specific characteristics of SCFs, mainly solvent power and liquid-like densities with gas-like transport properties, that can be tuned varying pressure and temperature. Among supercritical assisted micronization techniques, Supercritical Antisolvent (SAS) precipitation has been successfully used to obtain microparticles and nanoparticles of several kinds of compounds, such as pharmaceuticals, coloring matters, polymers and biopolymers. In this process carbon dioxide (CO2) is used as an antisolvent at supercritical conditions: a solution containing the product to be micronized is injected into the precipitation chamber, saturated with supercritical carbon dioxide under the chosen conditions of temperature and pressure. CO2, in contact with the solution, forms a mixture in which the product is insoluble, causing the precipitation... [edited by author]