Solid Lipid Nanoparticles (SLNs) with Potential as Cosmetic Hair Formulations Made from Otoba Wax and Ultrahigh Pressure Homogenization

The development and physicochemical characterization of solid lipid nanoparticles (SLNs) with potential for formulating hair cosmetic products were carried out. SLNs were made from Otoba wax, which is native to the tropical Andean region and has a high chemical composition of fatty acids with intermediate chains. SLNs were formulated by preparing wax-in-water dispersions at two internal phase proportions (low = 5% w/w and high = 20% w/w), using the same ratio of surfactant system and preservatives. The coarse dispersions were subjected to ultrahigh pressure homogenization (UHPH), and thermal stability assays for 4 weeks were carried out, where changes in Creaming Index, droplet size, polydispersity, viscosity, zeta potential, conductivity, and pH were evaluated. The results showed that Otoba wax has a required HLB value around 9 and is mainly composed of lauric (similar to 35%) and myristic (similar to 45%), which have been reported to improve the condition of hair loss. Regarding the development on SLNs, it was found that the internal phase concentration did not considerably affect the physicochemical and microbiological properties. Likewise, it was found that UHPH enabled the production of SLNs with particle sizes <200 nm, low polydispersity (<0.3), high zeta potential values, and suitable physical and microbiological stability. Therefore, Otoba wax has potential for the development of SLNs applicable to cosmetic formulations, especially for hair products.