The Study Of Vitamins A And E Nanoparticles/microparticles Double-layers Encapsulation System

Vitamin A is essential nutrition element for the maintenance of healthy body development, healthy skeletal, healthy vision and integrity of the immune system. It has functions as lipids antipreoxidation, enhance immunity and the ability of resisting infection, improve anemia arise from lack of iron. Vitamin E is natural lipophilic antioxidant. It can enhance immunity, has anti-cancer function, prevent heart and blood vessel diseases. However the application of these nutrients has been restricted due to their low aqueous solubility and bioavailability. Nanosphere/microsphere double-layers encapsulation delivery system is a possible route that is helpful to solve the aforementioned problems such as improve aqueous solubility, enhance bioavailability and provide multi-steps release.The preparation method and formulation of vitamins A and E nanosphere/microsphere double-layers encapsulation system were developed. The storage stability of vitamins A and E nanosphere/microsphere double-layers encapsulation system and the release rate of vitamins A and E nanosphere/microsphere double-layers encapsulation system in artificial simulation gastric and intestinal juices was determined.Vitamin A nanospheres suspension was prepared by hot homogenization which has emerged as a reliable technique. The results showed that the best formulation of nanosuspension with glycerin monostearate as wall material of nanosphere was the proportion between Tween-80, glycerin monostearate, vtiamin A and starch octenylsuccinate was 1:1.25:5:40 (w/w), the encapsulation efficiency (EE) of vitamin A nanospheres was 93.9%, the product yield was 70.47%, the average particle size (DZ) was 229.4nm. the best formulation of nanosuspension with beeswax as wall material of nanosphere was the proportion between beeswax and starch octenylsuccinate was 1:5 (w/w); the proportion between Tween-80, vtiamin A, beeswax and starch octenylsuccinate was 1:2:10:50(w/w), the encapsulation efficiency (EE) of vitamin A nanospheres was 93.41%, the product yield was 73.46%, the average particle size (DZ) was 335nm. The vitamins A and E nanosphere/microsphere double-layers encapsulation system was prepared by hot homogenization -spray drying technique. the proportion between vitamin E,nanospheres and wall material of microsphere starch octenylsuccinate was 1:2 (w/w), the optimum spray drying parameters were as follows: solid content was 40% (w/w), the inlet air temperature was around 185℃,the outlet air temperature was around 80℃, the homogenizing pressure was 40 MPa. the encapsulation efficiency of vitamins A and E and in the nanosphere/microsphere double-layers encapsulation system with glycerin monostearate as wall material of nanospheres was 92.97% and 93.9%; the encapsulation efficiency of vitamins A and E and in the nanosphere/microsphere double-layers encapsulation system with beeswax as wall material of nanospheres was 90.96% and 91.38%.The release study of vitamins A and E nanosphere/microsphere double-layers encapsulation system in artificial simulation gastric and intestinal juices showed that the release profile of the system when the beeswax as the wall material of nanopaticles was better than the system when the glycerin monostearate as the wall material of nanopaticles. Both of them exhibited a prolonged release profile. Pancreatin functions towards wall materials of both of nanospheres and microspheres. Vitamins A and E release faster in the intestinal juices with pancreatin.The storage stability of vitamins A and E nanosphere/microsphere double-layers encapsulation system was studied under different storing condition, the influence upon retention ratio from oxygen, light, temperature and humidity. The results show that retention ratio of vitamins A and E were 76% and 60% respectively with no change in appearance under condition of 4℃, light and oxygen avoiding, stored 100 days. The high temperature and high moisture have a great effect on the storage stability of products.SEM micrographs showed that vitamins A and E nanosphere/microsphere double-layers encapsulation product presented a smooth and compact surface without crack and broken microspheres which indicate the high encapsulation efficiency. The product with beeswax as wall material of nanospheres showed a smoother surface by comparation. Glass transition temperature (Tg) of vitamins A and E nanosphere/microsphere double-layers encapsulation product with glycerin monostearate as wall material of nanospheres by differential scanning calorimetry (DSC) was at 49.265℃with⊿Cp of 0.39J·g-1·℃-1; glass transition temperature of vitamins A and E nanosphere/microsphere double-layers encapsulation product with beeswax as wall material of nanospheres was at 47.51℃w ith⊿C p of 3.04J·g-1·℃-1which indicated the storage stability was good because both of the encapsulation products were at the glass state in normal temperature storage(25℃) .Thermogravimereic analysis(TGA) showed the thermal stability of the encapsulation product with different nanospheres wall material before and after stored 3 months. The encapsulation product with beeswax as nanospheres wall material showed better thermal stability. The moisture absorption of encapsulation product cause the change of thermogravimetry after 3 months.The results of X-ray diffraction and DSC analysis towards vitamins A and E nanosphere/microsphere double-layers encapsulation product and wall material indicated that glycerin monostearate intended to be supercooled melt which is in favor of encapsulation during recrystallization. But the vitamins would be expelled during modification of lopid thought storage. Beeswax displayed orthorhombic subcell packing(β'polymorph) which made the encapsulation product good physical stability during storage.