Preparation Of Nano-nutraceuticals Based On Zein By Supercritical CO₂ Antisolvent Precipitation

Zein is a natural biological macromolecules, with excellent biocompatible and biodegradable properties. It has already been reported as a sustained release drug carrier material, most of which are zein microspheres. Zein microspheres which were used to encapsulate, protect, and deliver active ingredients had good sustain-release properties, and took on good anti-pepsin decomposition characteristics. So zein is a good enteric coating material. And as natural biomacromolecules, food proteins are generally considered to be biocompatible and biodegradable. Further more, they are GRAS (generally regarded as safe) ingredients and have high nutritional value.Using supercritical CO2 to encapsulate bioactive substances is a newly developed method and has been widely used because of low critical temperature, pressure and no toxicity. Supercritical CO2 Antisolvent Precipitation(SAS), with its more feasible applications, has been given more attention.In this study, the drug carries based on zein was prepared using solution enhanced dispersion by supercritical fluids (SEDS), and its application in encapsulating lutein to prepare lutein/zein nanocapsules was investigated.Firstly, the preparation and the characterization of the zein nanoparticles. Zein nanoparticles was prepared from the acetone-DMSO mixed solution of zein using the SEDS process. The effects of temperature, pressure, zein solution concentration, flow rate of supercritical CO2 and solution were studied. SEM, Particle Size Analyzer, TGA, DSC were used to characterize the products. The result shows that the zein Nanoparticles with good sphericity and narrow size distribution could be prepared by SEDS process, and the mean diameters of the microspheres ranging between 160 nm and 400 nm could be obtained. Temperature, pressure and the concentration of the solution could influence the size of products, so the different size and distribution requirements of zein nanoparticles could be prepared through the selection of different process combinations. The TG analysis curves and DSC thermogram showed that the blank zein nanoparticles are more stable than the law zein.Secondly, the preparation and the characterization of the lutein/zein nanocapsules. Based on the preparation of blank zein nanoparticles, lutein was chosed as a model drug to prepare lutein/zein nanocapsules by SEDS process. The effects of temperature, pressure, zein solution concentration, ratio of lutein and zein, solution flow rate were studied. UV-Vis spectrometer, SEM, Particle Size Analyzer, DSC, XRD were used to characterize the products. The result shows that the lutein nanocapsules with high drug loading and high encapsulation efficiency could be prepared by SEDS process. Temperature, pressure, ratio of lutein and zein, solution flow rate can influence the size, drug loading and encapsulation efficiency of the lutein/zein nanocapsules. Lutein nanocapsules with drug loading of 5.87% and encapsulation efficiency of 60.38% could be prepared under the optimal conditions, at which the temperature is 45℃, pressure is 10MPa, ratio of lutein and zein is 1: 18, solution flow rate is 1mL/min. And the average particle size of nanocapsules was 205nm at that condition. The DSC thermogram and the XRD analyse showed that lutein was in the form of crystal in the lutein nanoparticles, and the lutein/zein nanocapsules were constituted by zein-covered lutein particles.Finally, we make a summary of the full text, point out the innovation and the lackness of the article, and make recommendations of the follow-up development.