The formulation optimization and properties of novel oleuropein-loaded nanocarriers

The present study sought to encapsulate oleuropein as a nutraceutical compound in order to investigate its physical properties and stability. We extracted the phenolic compounds of virgin olive leaf by ethanol–water and acetone–water solvents. The purity of this extract was confirmed by analytical high-performance liquid chromatography using oleuropein standard. Oleuropein was encapsulated with different components (lecithin, linoleic acid, glycerol monostearate, soybean oil, and Tween 80), and the effect of their contents on oleuropein-nanostructured lipid carrier (NLC) characteristics was checked by dynamic light scattering test. Moreover, several features of the optimal nanocarrier, including zeta potential, structural, morphology, stability, as well as thermal behavior were studied. The results of optimal NLC exhibited a high zeta potential as well as supreme stability versus aggregation. Thermal study indicated that oleuropein was well embedded into NLCs. The scanning electron microscope images showed that NLC samples had many spherical particles in the form of chain structure. The stable nanocarriers did not exhibit any oleuropein leakage following their analyses for 90 days at − 18, 6, and 25 °C in aqueous suspension.