Modeling of rapid expansion of supercritical solution (RESS) for an organic fluorinated tetraphenylporphyrin (TBTPP) was carried out applying mass, energy, momentum analogies and appropriate numerical technique. The results of RESS validated model demonstrated that increasing the pre-expansion temperature from 373 to 450 K produced 67% larger particles diameter due to the effect of higher growth mechanisms on materials agglomeration. On the contrary, higher pre-expansion pressure (from 187 to 280 bar) led to 14% smaller particles diameter. The numerical data indicated reducing nozzle diameter from 200 to 25 mu m resulted in 67% decreased particle diameter. Furthermore, 70% smaller particle sizes were obtained applying 98% lower expansion chamber pressure. Numerical results showed that operation of nozzle with addition of a capillary decreased the average particle diameter by 32%. (C) 2009 Elsevier B.V. All rights reserved.