Middle-chain triglyceride mixed with glyceryl tripalmitate or with carnauba wax, carnauba wax alone and middle-chain triglyceride alone formed stable lutein-loaded lipid nanocarriers. Particle size was affected by the lipid type. However, when the particles are incorporated in a viscous dermal formulation, diffusion velocity of the particles is reduced and even 40°C should be no problem anymore for the stability. The particles provided different release profile, which gives option to choose for a final dermal formulation. They showed good in vitro penetration, from relatively fast (nanoemulsion) to slowest with the SLN system. From the pig ear studies, systemic uptake can be excluded, which is good for a dermal formulation. The active remains in the skin. Remarkable is the photoprotection of the labile lutein achieved by the nanocarriers, being highest for SLNs(0.06% compared to 50% of lutein powder in oil).
https://doi.org/10.1016/j.ijpharm.2011.05.008
