In this study, ibuprofen, a common non-steroidal anti-inflammatory drug with low water-solubility was used as a model drug for its nanosizing via a PGSS (TM) (particles from gas-saturated solutions)-based method. A modified PGSS (TM), process was employed to prepare PEG6000-ibuprofen composite particles after investigating the solid-liquid-gas phase equilibrium behavior of the PEG6000-ibuprofen-CO2 system. The composite powder was then dispersed into water to remove PEG6000 and obtain ibuprofen nanoparticles. The effects of pressure, temperature, and mass fraction of ibuprofen in the composite on the ibuprofen particle size and particle morphology were investigated. Results showed that spherical ibuprofen nanoparticles with diameter of 20-500 nm were prepared at different conditions. Additionally, the dissolution rates of different ibuprofen particles were studied, indicating much faster dissolution of the obtained ibuprofen nanoparticles compared with the raw material and those from the direct physical mixing approach in the phosphate buffer solution (pH = 7.2 +/- 0.02). This can be attributed to the reduced size and the reduced crystallinity of the ibuprofen particles from the modified PGSS (TM)-based process. (C) 2013 Elsevier B.V. All rights reserved.