Isotretinoin-Loaded Solid-Lipid Nanoparticles: A Sound Strategy for Skin Targeting

The purpose of this research was to construct Isotretinoin-Loaded-Solid Lipid Nanoparticles (IST-SLNs) formulation with skin targeting for topical delivery of isotretinoin and study the effect of lipid matrix on the entrapment of isotretinoin. IST-SLNs were prepared using lipids like Glyceryl monostearate (GMS), Precirol ATO5 (PRE 5), Glyceryl tristearate (GTS), 1,2-dimyristoyl-sn-glycero-3 phosphoethanolamine (DMPE) -and soybean lecithin and Tween 80 as stabilizers using a hot homogenization technique, and then characterized by particle size analysis, zeta-potential and transmission electron microscopy (TEM). Precirol ATO and DMPE were selected as the suitable lipid of SLN. All the SLN formulations had low average size between 21nm and 50nm. TEM studies showed that the IST-SLNs formulation had a spherical shape. A significant increase in size and zeta potential was observed for GTS based and GMS based SLN dispersions stored at 40°C. The highest partition coefficient for IST between the melted lipid and pH 7.4 phosphate buffer was obtained with Precirol ATO5. The entrapment efficiency is as follows:

Pre 5-Slns≫Dmpe-Slns≫Gms-Slns≫Gts-Slns.

The penetration of isotretinoin from the IST-SLNs dispersed in cream base formulations through skins and into skins were evaluated in vitro using Franz diffusion cells fitted with rat and goat skins. The in-vitro permeation data showed that all the IST-SLN formulations can avoid the systemic uptake of isotretinoin in skins. The studied IST-SLNs showed a good stability. PRE 5 based SLNs showed 22.09±1.010% (in rat skin) and 33.02±1.032% (in goat skin) penetration of drug in skin, and had an enhanced skin targeting effect.