The effect of supercritical CO2 as a reversible plasticizer and foaming agent on the hot stage extrusion of itraconazole with EC 20 cps

The aim of the current research project was to explore the possibilities of combining pressurized carbon dioxide with hot stage extrusion during manufacturing of solid dispersions of itraconazole and ethylcellulose 20 cps (EC 20 cps), to evaluate the ability of the pressurized gas to act as a reversible plasticizer and to produce a foamed extrudate. The physicochemical characteristics of the extrudates with and without injection of carbon dioxide were evaluated with reference to the morphology of the solid dispersion, release characteristics of the drug, and particle properties. Carbon dioxide acted as a plasticizer for itraconazole/EC 20 cps, reducing the processing temperature during the hot stage extrusion process. The macroscopic morphology changed to a foam-like structure due to expansion of the carbon dioxide at the extrusion die. This resulted in increased specific surface area and porosity and as a consequence milling efficiency was improved.