Study On The Preparation Of Ubiquinol-10 Nanoliposome Compositions And The Stability

Coenzyme Q10, including the reduced form(Co Q10H2, ubiquinol) and the normal form(Co Q10,ubiquinone), is essential for producing adenosine triphosphate and antioxidation of human body. Co Q10H2 has more powerful ability of antioxidation, but is very easy to be oxidated and has poor solubility. Nanoliposomes can encapsulate lipophilic and hydrophilic substances at the same time. Thus, by using nanoliposomes to encapsulate Co Q10H2 and antioxidants together, the problem above-mentioned could be solved well.In this study, mixed lipid including egg yolk phospholipid and Tween 80 was chosen as wall materials, Co Q10H2 as well as vitamin E acetate(VE acetate) and ascorbic acid(Vc) were encapsulated together to form the nanoliposome compositions. Then, the optimum content of VE acetate and Vc was investigated. Furthremore, the effect of Co Q10H2 and antioxidants on the fluidity and structure of lipid bilayer was studied to reveal the mechanism of stabilization.By means of high performance liquid chromatography and dynamic light scattering, with the mass ratio of Co Q10H2 to the whole coenzyme Q10 as the index, the effect of liposome bilayers as well as alcohol-soluble and water-soluble antioxidants on Co Q10H2’s stability was investigated. The result showed that, the bilayers could defend the attack of oxygen well. And the addition of VE acetate and Vc could improve Co Q10H2’s stability further. When the molar ratio of VE acetate and Vc to Co Q10H2 was 1:1 and 3:1, respectively, the ratio of Co Q10H2 to the whole coenzyme Q10 in the composition was 99.6% as prepared. After 60 days’ storage in low temperature without light, Co Q10H2 reserved 88.3%, the retention rate of coenzyme Q10, VE acetate and Vc was 92.3%, 93.9% and 16.8%, respectively. Morover, malondialdehyde was inhibited obviously. The average particle size and polydispersity index maintained in low level, under 100 nm and 0.3, respectively.With the optimum additive amout of VE acetate and Vc, the storage stability and microstructure of compositions containing Co Q10H2 with different loading capacity was investigated. As result, Co Q10H2 could be protected well as the loading capacity changed from 12% to 48%(the molar ratio of Co Q10H2 to phospholipid, mol/mol). However, the encapsulation efficiency of coenzyme Q10 and VE acetate reduced sharply when compositions loaded Co Q10H2 more than 36%(mol/mol). The result of apparent morphology study indicated that, the particles of composition loading 12%~24%(mol/mol) of Co Q10H2 appeared spherical shape and dispersed uniformly. When the loading capacity exceeded 36%(mol/mol), the particles turned big and irregular, meanwhile aggregation of big particles was appeared. By means of nanoliposome encapsulation, the solubility of Co Q10H2 reached 3.84 mg/m L. As Co Q10H2’s loading capacity was 12%, the bioavailability of Co Q10H2 and VE acetate(mol/mol) was increased obviously in the nanoliposome system.The dynamic and structural properties of lipid bilayer was investigated by fluorescence probe, Raman spectroscopy and electron paramagnetic resonance to reveal the mechanism of Co Q10H2’ stabililization. The results showed that encapsulating 12%~24%(mol/mol) of Co Q10H2 and 6%~12%(mol/mol) of VE acetate could enhance the stability of lipid bilayer and reduce the fluidity. The loading of Vc, however, could not have an obvious impact on the structure of bilayer.