Nanocarriers for Drug Delivery by Supercritical Fluid Extraction of Emulsions

The advantage of the application of the supercritical extraction in contrast to the conventional methods to prepare micro and nanoparticles is that the product no longer is exposed to high temperatures for a long time. Furthermore, the supercritical extraction offers the possibility to reduce the content of the residual organic solvent in the final product because of the high solubility of organic solvents in supercritical fluids. This high solubility is due to the fact that the density of a supercritical fluid is nearly the same than the density of a liquid. In contrast to a liquid solvent which is used for the conventional extraction of emulsions, a supercritical fluid exhibits a diffusion coefficient in the same range than the one of a gas which leads to a very fast mass transfer. Because of this the mass transfer no longer is the limiting factor of a supercritical fluid extraction of emulsions. [4,5,6]