Nanostructured lipid carriers (NLC): The second generation of solid lipid nanoparticles

Abstract

Solid lipid nanoparticles (SLN) were invented in 1991 as a delivery system combining advantages of other nanoparticulate systems and at the same time avoiding/minimizing some of their limitations. In 1999/2000 the second generation of nano(structured) lipid carriers (NLC) was developed, showing improved properties such as increased drug loading and physical stability. Differences to the first generation are discussed. Large-scale production, incorporation of NLC concentrates in final dermal products, and accepted regulatory status of excipients – as prerequisites for market introduction – are presented. Special emphasis is also given to the problem of nanotoxicity/nanotolerability, considering the increasing concern in the public perception. The mechanisms of action are presented. As the most important criterion for the performance of a delivery system, in vivo data in the literature are reviewed. An overview of marketed dermal products (cosmetics) is given and the future for dermal pharma products and cosmetics forecasted.