The use of solid lipid matrices is known in pharmacy for many years, e.g. drug release from lipid pellets.
Solid lipid mircoparticles were introduced by Speiser et al. (Speiser, 1990; Eldem et al., 1991).
In the next step the size of the particles was further reduced to the nanosize yielding the lipid nanoparticles, the SLN and as a further development of the SLN the NLC.
For topical applied lipid nanoparticles all excipients, which used in the current topical cosmetic and dermal pharmaceutical products, can be used.
In addition, GRAS substances and substances with accepted GRAS status can be used.
The choice of the lipid matrix and surfactant is essential in order to formulate an optimal safe and stable formulation (Weyenberg et al., 2007).