Study On Preparation And Stability Of Nanoliposomes Encapsulating Typical Lipophilic Nutrients

The ethanol injection and sonication method was suitable to prepare coenzyme Q10 nanoliposomes at the laboratory scale. However, whether the process and formulation parameters of the method could be applied to other lipophilic nutrients such as vitamin and carotenoid should be further investigated. So, the objective of this study was to find the critical point of nanoliposomes encapsulating lipophilic nutrients and then regulate their preparation. Some typical lipophilic nutrient nanoliposomes were selected to compare the methods of preparation and their stability, taking the encapsulation efficiency (EE) and average particle size (Dz) of nanoliposomes as indices.It was found that the ethanol injection method was fit for incorporation of fat-soluble vitamins in nanoliposomes, whereas the encapsulation efficiency of vitamin A nanoliposomes was slightly lower, and the size of vitamin E liposomes was too large. By optimizing the preparation parameters and formulation, the content increase of cholesterol and Tween 80 would help to improve the encapsulation efficiency of vitamin A nanoliposomes; High pressure homogenization was efficient for vitamin E nanoliposomes. The optimal pressure of homogenization was 25000 PSI, and the samples are processed for one time. Thin film and homogenization method might increase the load capacity of lutin and lycopene in nanoliposomes, butβ-carotene and canthaxanthin were still difficult to be incorpoarated in lipoosmes and the particle sizes were large.The presence of lipophilic vitamins and carotenoid significantly inhibited the production of malondialdehyde (MDA) in liposomal system during storage at 4℃. Furthermore, proper amount of lipophilic nutrients suppressed the increase of the z-average diameter of nanoliposomes during storage. Lipophilic nutrients incorporation resulted in the increase of nanoliposomal bilayer microviscosity. As compared with the pure nanoliposomes, the bilayer fluidity of lipophilic nutrient nanoliposomes decreased which was helpful to keep the storage stability. The ability of lipophilic nutrients in occupying the hydrophobic domain of lipid bilayer was found as follows: vitamin K>vitamin D >vitamin E>vitamin A, lycopene>canthaxanthin≈β-carotene>lutein. The location of lipophilic nutrients in the bilayer was correlated with the stability of the liposomes. The nutrients in the hydrophobic domain could be better protected, while nutrients near the lipid-water interface were susceptible to the effects of the water environment.