Solid State Morphology of Particles Prepared by a Supercritical Fluid

The solid state morphology of many compounds is a key-parameter for their further utilization when several forms can co-exist either as crystalline and amorphous, and/or as different polymorphs (allotropes) ; this is particularly important for pharmaceutical drugs as their morphology can have a significant impact on their bio-availability and stability. Supercritical Fluid (SCF) technology is now considered to be an innovative and promising way to design particles, as reviewed by Kompella and Koushik (2001) and Jung and Perrut (2001). We present a review of the results already published in literature and our own results on morphology changes and stability of particles generated by SCF processes, focusing on neat particles and not on composite ones. Generally, a dramatic change of the solid morphology is observed after processing by SCF: Average particle size and size distribution, particle shape and porosity, and consequently, specific area and dissolution rate, are often completely different from those of the starting material However, it seem