Membrane emulsification: A promising alternative for vitamin E encapsulation within nano-emulsion

The purpose of our study was to develop a vitamin E-loaded nano-emulsion which could be a convenient drug carrier to be used for targeting the lungs. The nano-emulsion components (MCT oil and surfactant mixture Tween 80/Brij 35) were selected after solubility studies, and the concentration range was chosen after construction of ternary phase diagrams. For emulsion manufacturing, an SPG membrane emulsification process was developed. Key parameters influence on nano-emulsion characteristics was investigated. It has been established that small droplets and narrow size distribution were favored at low transmembrane pressure, high continuous phase flow rate and high agitation speed. Under optimal conditions, nano-emulsion with a span factor of 0.25 +/- 0.01, which meant high monodispersity, and an average size of 78 +/- 3 nm, was prepared. The high zeta potential of -22.9 +/- 0.9 mV was sufficient to prevent droplet coalescence. Vitamin E was successfully encapsulated within the optimized nano-emulsion with high entrapment efficiency value (99.7 +/- 0.4%). Transmission electron microscopy images revealed spherical-shaped and well-distributed nano-droplets. Additionally, special attention was paid on process reproducibility and preparations stability. Results confirmed the robustness of the optimized membrane emulsification technique which seems to be fast, simple and reliable. (c) 2012 Elsevier B.V. All rights reserved.