In this work polyvinylpirrolidone (PVP) has been successfully micronized using supercritical assisted atomization (SAA), using different solvents and solvent mixtures. The general influence of solvents is related to their starting surface tension and its reduction due to different quantities of CO2 that can be dissolved at equilibrium and under pressure. The influence of other SAA process parameters, such as temperature and pressure inside the saturator, has also been studied. Spherical non-coalescing PVP microparticles were produced; the smallest PVP particles showed a mean diameter of 0.5 mu m and a standard deviation of 0.2 mu m. (C) 2014 Elsevier B.V. All rights reserved.