Equilibrium data of the solubility of carbon dioxide in Precirol(R) ATO5, Compritol(R) 888 ATO and Gelucire(R) 43-01, three solid lipid carriers suitable for controlled/sustained delivery, were measured by a static analytical method for three different temperatures each, in a pressure range from 10 to 20 MPa. The influence of the presence of carbon dioxide in the melting point of the lipid matrices was also studied by a visual method for pressures up to 30 MPa. All the compounds studied presented a similar behaviour in the presence of carbon dioxide, showing a decrease in the melting points between 5 and 13 degrees C, whereas the solubility of carbon dioxide varies from 0.3 to 0.5 g/g of lipid compound. These results are of utmost importance to design supercritical fluid processes for particle formation at lower operating costs. (C) 2006 Elsevier B.V. All rights reserved.