Our research focuses on evaluating the preliminary stability of solid lipid nanoparticles (SLNs) in order to identify an optimal formulation for studying the skin penetration of SLNs loaded with sesamol, with a view to developing potential cosmetic applications. For this study, SLNs were prepared with varying lipid and surfactant compositions and produced through homogenization and ultrasonication. The particle size (PS), polydispersity index (PDI), zeta potential (ZP), and encapsulation efficiency (EE) were analyzed for the different formulations. We identified OP2Se as the optimal formulation for skin penetration assessment due to its stable PS, PDI, ZP, and EE over time, with a Turbiscan Stability Index (TSI) below 1 after a month, indicating favorable stability conditions. The in vitro skin permeation study compared sesamol-loaded SLNs with a control sesamol hydrogel, revealing controlled release characteristics ideal for localized skin effects without significant bloodstream penetration, attributed to the SLNs’ 200 nm particle size. Further exploration could enhance skin retention and targeting, potentially extending penetration studies and reducing particle size to improve accumulation in hair follicles. Exploring SLN applications beyond sesamol, such as incorporating mineral filters for suncare, offers promising avenues, underscoring SLNs’ versatility in cosmetic formulations and skincare applications.

Settled dusts are sinks for environmental pollutants, including Polycyclic Aromatic Hydrocarbons (PAHs) that are ubiquitous, persistent, and carcinogenic. To assess their toxicity in mixtures, Toxic Equivalent Factors (TEFs) are routinely used and based on the hypothesis of additive effects, although PAH interactions may occur and remain an open issue. This study investigated genotoxic binary interaction effects for six PAHs in mixtures using two in vitro assays and estimated Genotoxic Equivalent Factors (GEFs) to roughly predict the genotoxicity of PAH in mixtures. The Design of the Experiment approach was used with the micronucleus assay for cytostasis and micronuclei frequency and the alkaline comet assay for DNA damage. GEFs were determined for each PAH independently and in a mixture. For the cytostasis endpoint, no PAHs interaction was noted. BbF and BaP had a synergistic effect on DNA damage. All the PAH interacted between them regarding chromosomal damage. Although the calculated GEFs were similar to the TEFs, the latter may underestimate the genotoxic potential of a PAH mixture. GEFs calculated for PAH alone were lower than GEFs for PAHs in mixtures; thus, mixtures induce greater DNA/chromosomal damage than expected. This research helps to advance the challenging issue of contaminant mixtures’ effects on human health.