Lipid nanoparticles loaded in triterpenes acid-based extract from Malus domestica Borkh

Apple peel extract (LTU) (Malus domestica Borkh) shows a high content of ursolic acid (UA; 28.35%). Low solubility is a limiting factor for its bioavailability, which can be circumvented using nanostructured lipid carriers (NLC). Microemulsification with a lipid phase (5%): glyceryl monostearate and oleic acid, an aqueous phase: polisorbate 80 and compritol® 888ATO (1:1), and 0.7% of LTU was used to obtain NLCs. Nanoparticles were evaluated as to macroscopic characteristics, pH, zeta potential (ZP), particle size (PS) and polidispersivity (PDI). The most stable NLC (NLC-S) was characterized by atomic force microscopy (AFM), differential scanning calorimetry (DSC) and encapsulation efficiency (EE) determined by HPLC. NLC-S showed mean values of PS of 220.7 nm, PDI 0.175, ZP -24.7 mV and pH 6 after 21 days, which remained unaltered over 12 months. AFM revealed spherical particles with diameters under 300 nm. DSC analyses suggest almost complete encapsulation of LTU, confirmed by UA quantification.