Abstract: Liposomes were prepared by thin film evaporation and ultrasonic technique, and single factor test was adopted to study the effects of several factors in preparation on encapsulation efficiency. The shape, the particle size distribution, the Zeta potential and stability of medium chain fatty acid liposomes were investigated. The results indicated that the optimal prepara- tion conditions of medium chain fatty acid liposome were as follows: the ratio of soybean phosphatidylcholine to cholesterol 3: 1, the proportion of medium chain fatty acid and lipids in weight 1:10; the ratio of Tween-80 to total lipids 3:10 and the optimal temperature 35 ℃. In the optimal condition, the encapsulation efficiency could reach 82.9%, the mean particle size of liposome was 240.420.3 nm and the Zeta potential was -52.273.2 mV. The liposome was still stable after that stored for 90 days storage at 4 ℃.

Key words: medium chain fatty acid, liposome, thin film evaporation and ultrasonic technique