The desired features of pharmaceuti

The desired features of pharmaceutical drug delivery systems (DDS) for parenteral (itravenous)administration include their small size, biodegradability, high content of a drug in a final preparation,prolonged circulation in the blood, and, ideally, the ability to target required areas passively (via theenhanced permeability and retention-EPR-effect) or actively (via specific ligands, such as monoclonalantibodies). While these requirements are reasonably well met by a variety of DDS (liposomes,microcapsules, nanoparticles) for water-soluble drugs, the development of nanoparticulate DDSdisplaying all of these properties for poorly soluble pharmaceuticals still represents a challenge.'Low solubility in water, however, tends to be an intrinsic property of many drugs, including powerfulanti-cancer agents. This is not surprising, since the membrane permeability and efficacy of variousdrugs increase with increasing hydrophobicity.At the same time, intravenous administration of those