Lipid Nanoparticles (SLN^®, NLC^®) for Cutaneous Drug Delivery:Structure, Protection and Skin Effects

Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) are new drug delivery systems composed of physiological lipid materials and surfactants accepted by regulatory authorities for application in cutaneous drug delivery, i.e., topical, dermal and transdermal. They have a whole set of unique advantages which make them very reliable in the development of topical and dermatological formulations. This review article focuses on the definitions and properties of these colloidal carriers including the production techniques and suitable formulations. Pharmaceutical considerations are also addressed on the basis of physicochemical stability of such carriers as well as of drug retention onto the lipid matrix. The drug diffusion enhancing effect of SLN and NLC into the skin is also discussed. Advantages of these carriers on minimizing/avoiding skin side effects are also emphasized.