Preparation and Properties of Brij97-based Curcumin-encapsulated O/W Microemulsions

摘要

Oxidative damage is a public health issue in the modern world and promoting dietary anti-oxidants, such as curcumin, is a promising strategy. However, curcumin is unstable and poorly water-soluble and of poor bioavailability. This study constructed new curcumin-loaded O/W microemulsions using a pharmaceutically accepted Brij97 nonionic surfactant and evaluated several properties of curcumin encapsulated in the microemulsions. The pseudo-ternary phase diagram of Brij97/isopropyl alcohol/ethyl acetate/water system was determined and three microregions of the microemulsions—W/O, bicontinuous, and O/W—are identified by conductivity measurements, according to percolation theory. The properties investigation of a series of curcumin-loaded O/W microemulsions indicates: (1) The curcumin in such a situation performs sustained release following the first-order kinetics; (2) Better stability of curcumin to the sun light is observed over a time scale; (3) The curcumin presents relatively high anti-oxidant activity, with the IC_(50) in between 31.5 and 17.2 μg/ml on scavenging the superoxide radicals. In addition, the structure difference in the homologues acetate seems having no effect on the stability and release behavior of curcumin, while the investigated properties clearly depend on the ME/acetate ratio in the microemulsions. This study might be a potential help to the protection and the delivery of curcumin.