Study on food-grade vitamin E microemulsions based on nonionic emulsifiers

Phase diagram of water/vitamin E/oil/EL-35/ethanol system was determined. The effects of temperature and the concentration of NaCl aqueous solution on the microemulsion formation for this system were further investigated. The O/W, W/O and bicontinuous regions were divided by conductance method. The release rate of vitamin E from the microemulsion was studied with dialysis bag-Ultraviolet Spectrophotometer and the cytotoxicity assay of vitamin E in microemulsion was investigated with cancer cells H446. The results show that the influences of temperature and salinity on microemulsion region were very slight. However, the viscosity measurements along the selected dilution lines to the microemulsion indicate that when the water content was at 40% the system inverts from W/O to O/W microemulsion. The microemulsion enveloping vitamin E possessed eminent sustaining release efficiency that reached 86.7% within the first 10 h and the efficiency was further confirmed with the growth inhibitory effect test on human cancer cells H446.