Preparation And Application Of Nanostructured Lipid Carriers Loaded Coenzyme Q10

Nanostructured lipid carriers(NLC) were developed at the end of 20 th century. As a new generation of colloidal drug delivery system, NLC can solve the unstable and transportation problems of active components which have poor water solubility and biocompatibility. Therefore, NLC have great application potential in the carrier systems for cosmetic functional active. Coenzyme Q10(CoQ10) is a liposolube antioxidant which is often applied to anti-aging cosmetic. However, the unsaturated double bond in the molecular structure leads CoQ10 to be sensitive to light, which limits its processing and application in cosmetic industry. This study selected caprylyl/capryl glycoside(APG) as the surfactant to prepare the nanostructured lipid carriers loaded CoQ10(CoQ10-NLC) which could improve the storage stability and transdermal penetration of CoQ10. On the basis of this findings, quaternized chitosan(QCS) was added into the formulation to modify the surface of CoQ10-NLC and enhance the transdermal penetration of CoQ10. Finally, CoQ10-NLC modified by QCS(QCS-CoQ10-NLC) were applied to the skin care emulsions and the application characteristic of the skin care emulsions was measured.Firstly, mono-factor experiment was carried out to prepare CoQ10-NLC with the particle size, Zeta potential and encapsulation efficiency as indexes. The influence of mass ratio of the solid to liquid lipid, the mass fraction of the surfactant, the pressure and the cycle time of high pressure homogenization on the physical properties of CoQ10-NLC were investigated. The optimal preparation conditions were confirmed that the mass ratio of the solid to liquid lipid was 1:1, the mass fraction of the surfactant was 1.5%, the pressure of high pressure homogenization was 1000 bar and the cycle time was 7. The storage experiment showed that temperature had a large effect on the retention rate of CoQ10 and illumination had little effect. After stored for a month, the retention rate of CoQ10 was higher than 80% at the condition of 4℃, but at 40℃ the rentention rate of CoQ10 declined sharply. Additionally, in-vitro transdermal study showed that CoQ10-NLC could enhance the permeation of CoQ10 in skin.Secondly, CoQ10-NLC was modified by the penetration enhancer(QCS) to enhance the transdermal penetration of CoQ10. Two adding ways of QCS were compared by combining the self-aggregation of QCS with the compound of QCS and APG aqueous solutions. Method 1 was that CoQ10-NLC were first prepared, then mixed with QCS aqueous solution to form QCS-CoQ10-NLC. Method 2 was that QCS was first added into aqueous phase, then emulsified with lipid phase to form QCS-CoQ10-NLC directly. The results showed that the particle size of QCS-Co Q10-NLC prepared by Method 2 was 250~300 nm which was smaller than that prepared by Method 1, so Method 2 was chosen to prepare QCS-CoQ10-NLC for the follow-up study. In addition, the transdermal penetration of QCS-CoQ10-NLC was investigated by in-vitro transdermal study and characterized by confocal laser scanning microscopy(CLSM). The result showed that QCS-CoQ10-NLC could improve the transdermal penetration of CoQ10 in skin, especially in the epidermis. The permeability mechanism of QCS was analyzed by employing total reflection Fourier transform infrared spectrometer(FTIR). It was found that QCS could change the secondary structure of keratin in stratum corneum leading to a more loose accumulative structure of keratin, which could enhance the transdermal permeation of CoQ10. The storage experiment showed that the modification of QCS could improve the rentention rate of CoQ10 during storage.Finally, QCS-CoQ10-NLC were applied to skin care emulsions. Two contrast skin care emulsions that one didn’t contain NLC and one contained Co Q10 and blank NLC were also prepared to compare with the skin care emulsion containing QCS-CoQ10-NLC. Three emulsions presented good physical stability through the experiments of centrifugation, heat-resistant test and cold-resistant test. The temperature and illumination storage experiment showed that rentention rate of CoQ10 in QCS-CoQ10-NLC skin care emulsions was higher than the contrast emulsion containing CoQ10 and blank NLC, which meant QCS-CoQ10-NLC can provent CoQ10 from degradation and leakage in the emulsion. Meanwhile, the moisture test and sensory evaluation indicated that the addition of QCS-CoQ10-NLC in skin care emulsion could enhance the moisture retention, the solid feeling, the absorptivity and the retentivity.