Resumen: The low solubility of drugs and nutraceuticals in water decreases their bioavailability, which poses a serious challenge to the biotechnology industry. To improve this, several mixtures have been proposed. Here, the solubility and antioxidant capacity of quercetin in binary mixtures of oleic acid with geraniol and cinnamyl alcohol are determined. As a preliminary step, phase changes and thermophysical properties are discussed and modelled with the PC-SAFT EoS. The densities were between 6% at 283.15 K and 11% at 338.15 K lower than those of water. The surface tensions and viscosities were moderate and also decreased as the temperature increased. The equation of state correctly predicted the density and heat capacity, with average deviations less than 0.32% and 1.9%, respectively. The solubility of quercetin was favored in both mixtures. A synergistic effect on the antioxidant capacity was observed in the mixture with geraniol, which was the least compact. Idioma: Inglés DOI: 10.1016/j.molliq.2026.129573 Año: 2026 Publicado en: Journal of Molecular Liquids 454 (2026), 129573 [12 pp.] ISSN: 0167-7322 Financiación: info:eu-repo/grantAgreement/ES/DGA/E31-23R-PLATON Tipo y forma: Article (Published version) Área (Departamento): Área Química Física (Dpto. Química Física)