A supercritical fluid-based method is proposed to produce coenzyme Q(10) (CoQ(10)) nanoparticles. First, CoQ(10)/polyethylene glycol 6000 composite particles are prepared by a modified PGSS (particles from gas-saturated solutions) process with controlling the flow rate of the gas-saturated solution. Then, CoQ(10) nanoparticles are obtained by dissolving the composite particles into water. The effect of experimental variables of the modified PGSS process, including pressure, temperature, flow rate of the gas-saturated solution, and mass fraction of CoQ(10), on the CoQ(10) particle size and particle size distribution was investigated. Results show that CoQ(10) slurry product with a median diameter of 190 nm and yield of 89.8% can be prepared at an optimum condition (operating pressure of 25 MPa, operating temperature of 80 degrees C, gas-saturated solution flow rate of 1.02 mL/min, CoQ(10) mass fraction of 40% and nozzle diameter of 100 mu m) via the supercritical fluid-based method. (C) 2011 Elsevier B.V. All rights reserved.