The Particle from Gas Saturated Solutions process was successfully used to micronize solid dispersions containing hydrophilic carriers and a new chemical entity, YNS3107. By means of experimental design, the effects of several experimental parameters on micronization were investigated. Within the chosen experimental conditions, the results showed that the autoclave temperature, autoclave pressure, drug loading, flow rate of carbon dioxide and air pressure were significant parameters. During the optimization step, the most relevant parameters of the screening were optimized using a central composite design meanwhile other factors were kept constant. Optimal conditions were used to produce microparticles with a volume weighted mean diameter of 30.4 mu m. The closeness between the measured and predicted response, evaluated at 28.1 mu m, demonstrated the validity of the statistical analyses. Finally, an enhancement of the rate of dissolution of YNS3107 in the solid dispersion microparticles was measured using USP II dissolution test apparatus. (C) 2009 Elsevier B.V. All rights reserved.