Solvent/anti-solvent precipitation method was applied to investigate the influences of three operating parameters on size of curcumin nanoparticles in a microchannel. A three-factor, three-level Box-Behnken design (BBD) was applied to optimize the independent variables, volume ratios of anti-solvent to solvent, flow rate of drug solution, and curcumin concentration. The nano-curcumin in the range of 62-335 nm was obtained by addition of ethanol as the solvent; water as the anti-solvent and in presence of PVP as the stabilizer. Analysis of variation (ANOVA) showed that all of the three variables, and their interaction significantly affected on the size of the precipitated particles, as the model response. Validation of the optimization study, with 15 confirmatory runs, indicated a high degree of prognostic ability of response surface methodology in identifying favorable process condition for size reduction of curcumin nanoparticles. Under these conditions, a size of 63.12 nm was predicted for curcumin suspension. The prepared nanoparticles were characterized by particle size distribution and scanning electron microscopy
