ADVANCED DRUG DELIVERY SYSTEMS

When designing NCs for clinical applications it should be clear that their systemic administration generates important modifications. In particular the nonspecific interaction between NC surface and bloodstream proteins leads to the adsorption of opsonins on NCs forming the so-called “protein corona.” These proteins substantially change the bare material properties determining the removal of NCs from circulation by the reticuloendothelial system (RES) in the spleen and liver. The most common RES-escaping approaches are to formulate NCs with neutral surface charge by coating their surface with polyethylene glycol (PEG) and to use small size NCs. NCs with these features are called “stealth” NCs and can avoid the RES. Finally NCs should be nontoxic biodegradable biocompatible noninflammatory and nonimmunogenic.