Solid-Liquid Equilibrium of Binary and Ternary Mixtures of Lipids Under Higher Pressure of CO2 for PGSS Process Development

Solid-liquid equilibria of solid mixtures in compressed CO2 are very important in assessing the feasibility of gas-assisted micronization processes such as PGSS (Particles from Gas-Saturated Solution). The determination of solid-liquid transition temperatures, the eutectic temperature and the associated composition of the melt can be problematic and time-consuming. Such data are required in the construction of solid-liquid phase diagrams. This information is useful for the selection of appropriate operating conditions in the PGSS process. The use of high pressure differential scanning calorimetry (DSC) for the determination of solid-liquid transition temperatures of solid mixtures in high pressure CO2 provides a rapid and indirect method for the determination of the liquid-phase composition. A simple thermodynamic model was developed to predict the phase behaviour.