Encapsulation of resveratrol in rhamnolipid-zein nanoparticles using a pH-driven method: kinetic modeling on controlled release from nanoparticles

Abstract

In this study, the encapsulation of resveratrol (Res) in zein-rhamnolipid (RL) composite nanoparticles (NPs) by a pH-driven method and its relationship with the controlled release behavior of the NPs were investigated. The properties of the produced NPs were elucidated with different zein-RL mass ratios and encapsulation of different amounts of Res. The NPs had relatively high encapsulation efficiency, loading capacity, stability, and cumulative release percentages. The SEM analysis showed the spherical NPs obtained with and without Res incorporation and the FTIR study indicated the interactions of Res with zein-RL components. The NPs had relatively good stability over a wide range of pH (4–9), salt concentration (0–200 mM) (pH = 7), and Res amount (0–160 mg) (pH = 7.4). Ultrasonic and shaking water baths were used for release studies of Res from NPs with an optimum zein-RL mass ratio of 1.0:0.6 (w/w). In vitro release studies of Res under acidic (pH = 1.2) and neutral (pH = 7.4) conditions demonstrated initial rapid release followed by slow release. The highest cumulative release percentage was obtained at pH 1.2 and 7.4 with 120 mg Res encapsulated zein-RL NPs. The release of Res from the capsules was a pH-dependent process and the cumulative release profiles were considered to be slightly higher in acidic environments. Among the controlled release kinetic models, the Weibull model gave the best fit for optimum Res-loaded NPs. Release studies indicated that zein-RL NPs have the potential to be used as delivery systems for health-promoting bioactive molecules in functional foods, nutraceutical/dietary supplements, and pharmaceutical formulations.