TITLE:
Solid Lipid Nanoparticles (SLN) and Nanostructured Lipid Carriers (NLC): Occlusive Effect and Penetration Enhancement Ability
AUTHORS:
R. López-García, A. Ganem-Rondero
KEYWORDS:
Solid Lipid Nanoparticles, Nanostructured Lipid Carriers, Occlusive Effect, Transepidermal Water Loss, Skin Penetration
JOURNAL NAME:
Journal of Cosmetics, Dermatological Sciences and Applications,
Vol.5 No.2,
May
28,
2015
ABSTRACT: Objective:
This work compares the occlusive effect and the penetration enhancement ability
of solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC),
through in vitro skin. Methods: SLN
and NLC were prepared by high shear homogenization and characterized by size,
polydispersity index, zeta potential, morphology and physical stability.
Occlusive effect was assessed by an in
vitro test and by measuring TEWL using pig skin. Skin treated with the
lipid carriers was visualized by SEM. A penetration test through skin, followed
by tape stripping, was carried out using Nile red as a marker. Results: SLN
(200 ± 6 nm) and NLC (192 ± 11 nm) were obtained. An occlusion factor of 36% -
39% was observed for both systems, while a reduction in TEWL of 34.3% ± 14.8%
and 26.2% ± 6.5% was seen after treatment with SLN and NLC, respectively. SEM
images showed a film formed by the lipid carriers, responsible for the
occlusion observed. No differences were found between the occlusive effect
produced by SLN and NLC in both tests. NLC allowed the penetration of a greater
amount of Nile red than SLN: 4.7 ± 1.3 μg and 1.7 ± 0.4 μg, respectively. Conclusion:
Both carriers form a film on the skin, providing an occlusive effect with no
differences between these two systems. The penetration of a marker (Nile red)
into the stratum corneum was quite higher for NLC than for SLN, suggesting an
influence of the composition of these particles on their penetration enhancing
ability.