The development of solid lipid nanoparticles (SLN) using supercritical fluid at room temperature is an innovative alternative compared to traditional pharmaceutical methods and the safety and drug efficacy of SLN made using supercritical CO2 is increased. One of the micronization techniques which have provided the best results in the production of SLN is particles from gas- saturated solution (PGSS). The solid- liquid- vapour coexistence curve of a solid in a compressed gas is of primary importance in assessing the feasibility of PGSS and the selection of appropriate operating conditions. The objectives of this work are to perform experimental measurements using a high pressure differential scanning calorimeter (DSC) to obtain melting properties as a function of composition and develop a simplified approach to model multiphase equilibria of lipids in compressed CO2. The selected lipid was tristearin. Before assessment of triestearin and CO2 phase equilibrium, the performance of this thermodynamic model was evaluated in two other lipids which provided results with high accuracy. (C) 2013 Elsevier Ltd. All rights reserved.