ABSTRACT
Drug delivery systems (DDS) are designed to improve the pharmacological and therapeutic properties of drugs administered in vivo, and DDS include particle carriers that can function as drug reservoirs. Drug carrier systems allow for the controlled release of drugs at the desired sites, thus altering the pharmacokinetics and biodistribution of the drugs. In this sense, nanoparticles are intrinsically advantageous over conventional particles. The pharmacokinetics of particle DDS is largely affected by splenic ltration, which occurs at the interendothelial cell slits (<200 nm) in the walls of venous sinuses. Furthermore, vesicles larger than 100 nm must be designed to prevent surface opsonization processes, which lead to phagocytic uptake of the particles in the liver. Taken together, nanoparticles can be a long-circulatory drug carrier. Based on the enhanced permeability and retention effect, this kind of DDS is useful for cancer chemotherapy.
