Solid Lipid Nanoparticles (SLN) and Nanostructured Lipid Carriers (NLC): Occlusive Effect and Penetration Enhancement Ability

R López-García,A Ganem-Rondero

doi:10.4236/jcdsa.2015.52008

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.

Highlights

Nanotechnology is a highly useful tool for the design of innovative solutions for many sciences including health and beauty
According to the tests performed, both Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) produced an occlusive effect of similar magnitude, which is due to the ability of lipid nanoparticles to form a film
No differences were found between film appearance and the occlusive effect degree produced by both SLN and NLC, suggesting that differences in composition did not affect those parameters

Summary

Introduction

Nanotechnology is a highly useful tool for the design of innovative solutions for many sciences including health and beauty. Solid lipid nanoparticles (SLN) were developed at the beginning of the 1990’s based on the concept of solid particles, emulsions and liposomes. They are produced by exchanging the oil in an emulsion by a solid lipid, resulting in lipid nanoparticles being solid at both room and body temperature [1]. The second generation of lipid nanoparticles, nanostructured lipid carriers (NLC) which are prepared by blending solid and liquid lipids leading to amorphous solids, arose to overcome limitations of SLN by introducing a less ordered inner structure [3]

Methods

Results

Conclusion