Nanostructured Lipid Carriers (NLC) as Vehicles for Topical Administration of Sesamol: In Vitro Percutaneous Absorption Study and Evaluation of Antioxidant Activity.

Sesamol is a natural phenolic compound extracted from Sesamum indicum seed oil. Sesamol is endowed with several beneficial effects, but its use as a topical agent is strongly compromised by unfavorable chemical-physical properties. Therefore, to improve its characteristics, the aim of the present work was the formulation of nanostructured lipid carriers as drug delivery systems for topical administration of sesamol.Two different nanostructured lipid carrier systems have been produced based on the same solid lipid (Compritol® 888 ATO) but in a mixture with two different kinds of oil phase such as Miglyol® 812 (nanostructured lipid carrier-M) and sesame oil (nanostructured lipid carrier-PLUS). Morphology and dimensional distribution of nanostructured lipid carriers have been characterized by differential scanning calorimetry and photon correlation spectroscopy, respectively. The release pattern of sesamol from nanostructured lipid carriers was evaluated in vitro determining drug percutaneous absorption through excised human skin. Furthermore, an oxygen radical absorbance capacity assay was used to determine their antioxidant activity.From the results obtained, the method used to formulate nanostructured lipid carriers led to a homogeneous dispersion of particles in a nanometric range. Sesamol has been encapsulated efficiently in both nanostructured lipid carriers, with higher encapsulation efficiency values (> 90 %) when sesame oil was used as the oil phase (nanostructured lipid carrier-PLUS). In vitro evidences show that nanostructured lipid carrier dispersions were able to control the rate of sesamol diffusion through the skin, with respect to the reference formulations.Furthermore, the oxygen radical absorbance capacity assay pointed out an interesting and prolonged antioxidant activity of sesamol, especially when vehiculated by nanostructured lipid carrier-PLUS.

In vitro Percutaneous Absorption of Niacinamide and Phytosterols and in vivo Evaluation of their Effect on Skin Barrier Recovery.

In this study, we evaluated different strategies to optimize the percutaneous absorption of niacinamide (NA) and soy phytosterols (FITO) by making use of solid lipid nanoparticles (SLN) and penetration enhancers, such as the hydrogenated lecithin. The evaluation of the skin permeation of NA and FITO has been effected in vitro using excised human skin (i.e., stratum corneum-epidermis or SCE). Furthermore, we evaluated the in vivo effect that NA and FITO has on skin barrier recovery after the topical application; using the extent of methyl nicotinate (MN)-induced erythema in damaged skin as a parameter to determine the rate of stratum corneum recovery. Results pointed out the importance of these strategies as valid tools for NA and FITO topical delivery. In fact, soy lecithin based formulations were able to increase the percutaneous absorption of the two active ingredients, while SLN guaranteed an interesting delayed and sustained release of FITO. In vivo evaluation showed clearly that the formulation containing both the actives (NA and FITO) is able to recover about 95% of skin barrier integrity eight days after tape stripping. This effect is probably due to the "synergistic effect" of NA and FITO.