Fabrication of polysaccharide-coated oleanolic acid-curcumin-coassembled nanoparticles (OA/Cur NPs): Enhancement of colloidal stability and water solubility

Natural terpenoid carriers, such as oleanolic acid (OA), can enhance the water solubility and stability of hydrophobic compounds such as curcumin (Cur). However, improving the colloidal stability of nanoparticle emulsions and resolving the redispersion problem of freeze-dried nanoparticle powders remain significant challenges. In this study, we fabricated coassembled oleanolic acid-curcumin nanoparticles (OA/Cur NPs) and applied a polysaccharide surface coating method to improve their colloidal stability and water solubility. The results showed that the optimal ratio of Cur/OA for preparing OA/Cur NPs was 4:10, resulting in a high encapsulation efficiency (EE) of Cur (75.2%). Additionally, TEM, contact angle tests, Turbiscan TOWER optical stability analysis of the polysaccharide-coated OA/Cur NP emulsions and redispersion tests of their lyophilized powders verified the advantages of carboxymethyl chitosan/β-cyclodextrin (CMC/β-CD) coating over other polysaccharides. This study indicated that polysaccharide coating is an effective method for enhancing the colloidal stability, water solubility, and redispersibility of OA/Cur NPs.