Hybridization of polyvinylpyrrolidone to a binary composite of curcumin/α-glucosyl stevia improves both oral absorption and photochemical stability of curcumin

The tri-component system curcumin/α-glucosyl stevia (Stevia-G)/polyvinylpyrrolidone (PVP) was developed to improve the oral bioavailability and physicochemical properties of curcumin (CUR). The tri-component CUR formulation with Stevia-G and PVP was prepared with freeze-drying. The tri-component CUR system exhibited 13,000-fold higher solubility of CUR than the equilibrium solubility of CUR for 24 h, indicating a stable tri-composite structure involving CUR. CUR could be converted into an amorphous form in the presence of Stevia-G and PVP by freeze-drying. The photo-degradation of CUR in the tri-component system was negligible even under an amorphous state of CUR. After oral administration in rats, the oral absorption of the tri-component CUR formulation (20 mg CUR/kg) was 6.7-fold higher than that of crystalline CUR. The tri-component CUR formulation would therefore be a promising option to improve physicochemical properties and oral absorption of CUR.