Stable oleogel system for improved delivery of poorly soluble quercetin

Abstract

Oleogels have emerged as promising systems for the encapsulation and sustained release of bioactive compounds. In this study, we developed a highly stable oleogel formulation by integrating two conventional techniques: the solvent evaporation method and the use of ethanol as a co-solvent. This approach enabled the successful encapsulation of bioactive compounds with poor lipophilicity and low water solubility, such as quercetin. Characterization by polarized light microscopy and X-ray diffraction revealed that ethanol played a dual role: it not only optimized the crystalline structure of the oleogel but also facilitated the formation of an amorphous solid dispersion of quercetin. This structural transformation significantly enhanced the oleogel's loading capacity and improved the bioaccessibility of compounds with low water and lipid solubility like quercetin. Furthermore, the three-dimensional network of the oleogel provided a protective matrix that reduced molecular aggregation and recrystallization, thereby enhancing the chemical stability of quercetin. In vitro simulated digestion studies demonstrated that the oleogel effectively delayed the digestion of sea buckthorn fruit oil in the gastrointestinal tract, leading to a sustained release of quercetin. This stable oleogel system presents a promising strategy for the efficient delivery of poorly soluble bioactive compounds and holds great potential for applications in the fields of nutraceuticals and functional foods.