Bioactive-fat engineered nanostructured lipid carriers from Illipe butter: optimized design and enhanced in vitro anti-inflammatory performance

Despite the extensive use of synthetic and semi-synthetic lipids in nanostructured lipid carrier (NLC) systems, the utilization of Shorea spp. (Illipe butter or tengkawang fat), an indigenous natural solid lipid from Indonesia, remains unexplored. This study aimed to develop and optimize a Nanostructured Lipid Carrier (NLC) formulation using Illipe butter (Shorea spp.) as a natural solid lipid source. The NLC system was designed through a Box-Behnken design to evaluate the influence of solid lipid (Illipe butter and glyceryl monostearate), liquid lipid (oleic acid), and surfactant mixture (Tween 80 and glycerin) on physicochemical characteristics. The optimized formulation Nanostructured Lipid Carrier-Illipe Butter (NLC-IB) was incorporated into a gel base to produce an NLC gel formulation suitable for topical anti-inflammatory application. Characterization of the optimized NLC revealed a particle size of 276.9 nm, PDI of 0.393, and zeta potential of - 53.5 mV, indicating good stability. Transmission electron microscopy showed spherical particles with an imperfect crystal (Type I) matrix. GC-MS analysis confirmed the retention of major fatty acids, particularly stearic acid (31.9%) and palmitic acid (18.2%), in the NLC system. In vitro anti-inflammatory evaluation using the BSA denaturation assay demonstrated moderate activity, with IC₅₀ values of 197.23 ppm (Illipe butter), 146.46 ppm (NLC-IB), and 238.49 ppm (E-NLC-IB). To our knowledge, this study represents one of the first systematic investigations of Illipe butter (Shorea spp.) as a solid lipid matrix in nanostructured lipid carrier systems.