卵磷脂/正丙醇/肉豆蔻酸异丙酯/水微乳体系的相结构研究

以卵磷脂为表面活性剂，正丙醇为助表面活性剂，肉豆蔻酸异丙酯(IPM)为油相，配制成W/O型微乳。并通过浊点法、电导法、动态光散射法(DLS)以及差示扫描量热法(DSC)研究了微乳相结构随含水量的变化。对于选定配比微乳，浊点法在含水量超过10.71%时变浑浊；电导率在含水量达到3.85%之前增长缓慢，之后快速增大，含水量超过10.71%时电导率下降；DLS显示微乳粒径随含水量先减小后增大，其转折点在5.66%，而含水量超过10.71%后粒径突增3个数量级；DSC曲线在含水量超过3.85%后出现水的结晶峰，且随含水量的增大峰位往高温方向平移，同时峰面积增大。当含水量达到11.5%时出现两水峰叠加。研究表明含水量在3.85%~5.66%范围内属于W/O向双连续相转变的过程，而含水量10.71%则是体系发生相分离的临界点。

Investigation on Phase Structure of Lecithin/n-Propanol/Isopropyl Myristate/Water Microemulsion Formulation

Microemulsion(W/O) formulations were prepared using lecithin as a surfactant,isopropyl myristate as the oil phase,n propanol as cosurfactant,and water.Influence of water content on the phase behavior of the microemulsion system was evaluated via the conductivity method,visual examination,dynamic light scattering(DLS) and differential scanning calorimetry(DSC).The results showed that,the microemulsion became cloudy when its water content was up to 11.5% in the visual examination.The conductivity increased slowly before water content reached 3.85%,and then followed a rapid increase until 10.71% at which the conductivity turned to decrease.The microemulsion droplet sizes assessed by DLS decreased firstly,and then increased as water content increased,the turning point was at 5.66%.After reaching 10.71% of water content,droplet sizes increased dramatically by three orders of magnitude.DSC curves revealed that microemulsion did not show water freezing peak until water content came up to 3.85%.With the increase of water content,the water freezing peak shifted towards high temperature and peak area increased linearly.However,the freezing peak divided into two at water content of 11.5%.Based on the study results,it could be deduced that phase structure transition point from W/O to Bi-continuous were in water content from about 3.85% to 5.66%,while the system was turned to phase separation at 10.71%.