Nanosized Drug Delivery Systems: Colloids and Gels for Site Specific Targeting

Recent advances in nanomedicine and biomaterials have provided new promising tools for in vitro models and targeted drug administration in vivo, aiming to increase efficacy while limiting side effects. Nanosized drug delivery systems are designed to modify the biodistribution of therapeutic agents, in order to enhance their accumulation in the pathological site. Bioactive molecules can be either conjugated to or entrapped into colloidal nanocarriers. Biocompatible nanoparticles (NPs), polymer nanotherapeutics, lipid-based nanomaterials may enhance the stability and the targeted delivery of low molecular weight drugs, as well as nucleic acids and therapeutic proteins. Once administered in vivo, these colloids will face sequential biological barriers, which represent a major challenge for site specific drug delivery. A fine control of key physicochemical characteristics of the nanocarriers, including size, drug loading, and functionality, may lead to a successful barrier penetration and an effective release at the targeted site.