Development and evaluation of tea polyphenols loaded water in oil emulsion with zein as stabilizer

Abstract

In this study, we have developed the optimal formulation for tea polyphenols-loaded emulsion (TPE) using zein as a stabilizer. The characteristics of and the stability of TPE were studied and the vitro drug release of the emulsion was also evaluated. The water-in-oil emulsion was produced via the mechanical method using grape oil as oil phase and tea polyphenol aqueous solution as water phase. Zein and surfactants (Tween 80 and Span 80) were applied as the emulsifier. The optimal formulation of the TPE is that the mass ratio of oil-water was 8 : 10, the surfactant content is 25 wt% (weight), and the HLB is 5.49. The emulsion had an average particle size of 3.43 μm and a drug loading of 0.053%. The emulsion shows good storage stability at 4 °C, 25 °C and 40 °C for 30 day and good freeze-thaw stability (30 times). It remained stable after centrifugation at 4000 r/min for 15 min but layered after high speed centrifugation at 15000 r/min. It released achieve 82.5 ± 0.2% in 6 h in vitro at the pH values of 1.2, 4.5, 6.8 and 7.4.