Lipid nanoparticles with solid particle matrix are derived from o/w
emulsions by simply replacing the liquid lipid (oil) by a solid lipid, i.e. being solid at
body temperature. The first generation of solid lipid nanoparticles (SLN) was developed
at the beginning of the nineties. They were produced from a solid lipid only. In the
second generation technology of the nanostructured lipid carriers (NLC), the particles
are produced by using a blend of a solid lipid with a liquid lipid, this blend also being
solid at body temperature. The production process is identical for both particles SLN
and NLC. The solid lipid or lipid blend is melted, the pharmaceutical or cosmetic
active dissolved in the melted lipid phase which is subsequently dispersed by high
speed stirring in a hot aqueous surfactant/stabilizer solution of equivalent temperature.