Low water solubility of a high percentage of pharmaceuticals is a big issue for pharmaceutical applications due to the resulting low bioabsorption and hence limited therapeutic efficacy. Preparation of drug nanoparticles has been one of the mostly investigated routes to address this problem. In this study, we reported the preparation of nanoparticles via an emulsion-freeze-drying approach. Indomethacin (IMC, a poorly water-soluble drug) nanoparticles were formed in situ within porous poly(vinyl alcohol). The IMC nanoparticles could be released into water to form stable nanodispersions simply by rapid dissolution of the porous polymeric scaffold. This study focused on how preparation conditions including phase volume ratios in the emulsions and the concentrations of polymer, surfactant and drug influenced the formation of IMC nanoparticles. It was concluded that the loading and size of IMC nanoparticles could be easily tuned by changing the preparation conditions. (C) 2011 Elsevier Inc. All rights reserved.