The Separation And Preparation Of Sugar Esters And Their Effects On The Stability Of Phospholipids-Vesicles Nanosystem

With the development of nanotechnology and drug controlled release system, the application of lipid vesicles like liposomes and ethosomes in pharmaceutical and cosmetic fields has attracted increasing attention in the past decades. However, the instability of the vesicles caused by aggregation, oxidation and leakage of target substance may occur during storage. These uncertain factors prevent the utilization of the nano-vesicles. Tween, PEG series as stabilizers are mainly used for their preparation, but the result is not satisfactory. Sugar esters (SEs), as surfactants, are odorless, tasteless, nature-derived, nontoxic, biocompatible, non-irritant and biodegradable. Moreover, lots of current studies indicate that SEs, playing an important role in the controlled release system, can enhance drug dissolution, absorption and permeation, improve the tablet properties, and sustain the release rate of the highly soluble drug. Therefore, sugar esters may be used as stabilizer in ethosomes and liposomes.In this study, firstly, digalactose ester, trigalactose ester and quadrigalactose ester were prepared from pumpkin extract by high-speed current chromatography (HSCCC) using a apparatus equipped with columns of15L; and sucrose monoester, diester, polyester were prepared from a commercial product of sucrose esters by HSCCC. And then, the above sugar esters were investigated for the effects on the stability of the ethosomes and liposomes by analyzing the changes in exterior, microstructure, size and size distribution, zeta potential, leakage of encapsulated VE during1,3,6months of storage at4℃. The results were as follows:(1) Sucrose ester and galactose ester were able to improve the stability of ethosomes. With the increase of sucrose ester esterification degree and the increase of the quantity of galactose, the stability was enhanced correspondingly. Sucrose polyester showed the best effect for preparing stable ethosomes which afforded particle size62.0±4.3nm, zeta potential-72.3±4.5mV and little change during6months of storage.(2) Sucrose ester could also improve the stability of liposomes which gave particle size84.0±4.2nm, zeta potential-52.4±3.4mV and little change during6months of storage.In conclusion, sugar esters may be used as a good stabilizer for phospholipids-vesicles nanosystem.