The influence of the crystallinity of lipid nanoparticles on their occlusive properties

The aim of this study was the investigation of the correlation between the degree of crystallinity of solid lipid nanoparticle (SLN) dispersions and their occlusive effects. SLN dispersions with different crystallinity indices of the lipid matrix were produced, physicochemically characterized and their occlusion factor was determined after 6, 24 and 48 h. This study is based on the in vitro occlusion test by de Vringer. It could be shown that the occlusion factor depends strongly on the degree of crystallinity of the lipid matrix, i.e. this effect is proportional. Further, it could be shown that noncrystalline lipid nanoparticles, i.e. supercooled melts have no occlusive properties. Therefore, the desired degree of occlusivity can be achieved by choosing suitable lipids for the matrices of topical SLN formulations. (C) 2002 Elsevier Science B.V. All rights reserved.