Occlusive effect of SLN and NLC was determined using a modified in vitro occlusion test [18]. Briefly, bakers were filled with 40 mL of water and covered with Whatman® filter paper grade 42 (Sigma-Aldrich, USA). A sample of SLN or NLC (300 μL, 10% w/v lipid content) was spread on the filter surface, using water as reference, instead lipid carriers. Bakers were stored at 32 ̊C to mimic the temperature of skin surface and weighted at 0, 6, 24 and 48 h to calculate water evaporation through the filter paper in terms of water loss. The occlusion factor F was calculated at 6, 24 and 48 h using Equation (1) [18]