Manufacture, Characterization, and Applications of Solid Lipid Nanoparticles as Drug Delivery Systems

A large number of drug substances are characterized by poor solubility in aqueous media, which may cause formulation problems. Encapsulation in colloidal carrier systems is an alternativeway to render poorlywater-soluble drugs applicable by parenteral andnonparenteral routes. The particulate carriermay also protect the drug fromdegradation in biological fluids. Furthermore, incorporation of drugs in particulate carriers provides a possibility to manipulate drug release and to alter the biodistribution of drugs. In this context, colloidal carrier systems have attracted growing interest concerning drug delivery to site-specific targets, especially in cancer chemotherapy (1-3). During the last decades, several approaches have been used to develop submicron-size drug delivery systems. Based on the carrier material, the conventional vehicles can generally be divided into two groups: polymeric and lipidic systems.