The Study On Preparation Of Nanoliposome By Supercritical Carbon Dioxide Fluid Technique

Nano-liposomes is a kind of nano-carrier systems with highly potential,it is hydrophilic lipophilic,targeted,non-immunogenic properties,non-toxic,fast absorption, high bioavailability,convenient delivery,not only used as drugs and nutritional factors,as well as the targeting vector gene technology tools,and natural phospholipids nanoliposomes itself also has to clear the vessel wall cholesterol,soften blood vessels, improve the immune function,such as health care.It can be widely used in medicine, health food,the field of cosmetics and genetic engineering.At present,however, nanoliposomes preparation method has been to stay in the laboratory phase of difficulties in scaling up,while there are still poor stability,residual solvent,preparation and time-consuming,low yield,high cost,which is very expensive and so on,can not be met health care products,cosmetics and other areas of high demand liposomes,resulting in its application mainly concentrated in the targeted drugs.This issue use vitamin C as model nutrients to prepare nano-liposomes by supercritical carbon dioxide fluid technology.The use of Sephadex chromatography and the envelopment rate in varies preparation conditions were studied.The results are as follows:(1)Mathod of supercritical carbon dioxide pressurized can be effectively prepared nanoliposomes.(2)Used Sephadex chromatography to separate liposomes and free vitamin C in suspension,the specific conditions are as follows:column packing:Sephadex G50 (100-300μm),chromatography columns:18mm×30cm,eluate:PBS buffer solution, 0.1mol/L,pH=7.0;on sample volume:1mL;sample concentration:the original concentration,no dilution;flow rate:1mL/min.Under these conditions,the liposome and free vitamin C in the suspension get a better separation,liposomes concentrated in 30min-50min outflow part and free vitamin C concentrated in the 70min-110min outflow. Collected the outflow at different times to achieve the separation of the liposomes and free vitamin C.(3) Preparation conditions of supercritical fluid(supercritical stress,time, temperature) is not significantly affected on the envelopment rate of liposomes.Material ratio have a greater impact.Researched the combined effects by orthogonal experimental. results show that:when the ratio of PBS buffer solution and ethanol solution is 6:1 volume, vitamin C concentration is 1mg/mL,lecithin and cholesterol mass ratio is 3:1,lecithin concentration is 20mg/mL,the liposome envelopment rate reached the maximum,up to 83.6%.(4) Transmission electron microscopy(TEM) observation and photographs show that liposome vesicles prepared by supercritical carbon dioxide pressurized is a single structure. Preparation pressure has a significant impact on the liposome size and zeta potential.When the pressure increased,liposome size get smaller,zeta potential increased.When the pressure reached more than 20MPa,the size of liposomes decreased to the average particle size of about 150nm below the minimum particle size less than 80nm,basically to achieve nanometer-level,zeta potential reaches 30mV.Which reach the needs of preparing nanoliposomes.(5)Vitro hemolysis experimental results show that the nano-liposomes suspension did not occur hemolysis at dilution of 10-100 times,can be used safely.