| Allium cepa L.var. agrogatum Don （ACAD） is a perennial herbal flavonoid-richfood of the Liliaceae family native to northern China. These extracts are not only usedas flavoring and coloring agents but also for promoting beneficial health effects.The Allium cepa L. var agrogatum Don flavonoid-rich （ACADF） is activecompounds of ACAD. Quercetin（QT,157.9±23.1mg/g）,quercetin-4’-O-β-D-glucopyranoside（181.7±25.4mg/g） andquercetin-3,4’-O-β-D-glucopyranoside（199.3±27.8mg/g） are the predominantcomponents of ACADF. ACADF exhibits multiple biological activities, includingantihyperlipidemic activity, blood fat regulatory activity, anti-atherosclerosis activity,preventing oxidative damage, antibacterial antitumor and so on. At present there is nopreparation in clinical application, ACADF is expected to be developed into a drug inclinical treatment for cardiovascular system. But the main component quercetin haspoor water solubility, which affects the absorption and biological availability in vivo.Nanoemulsions, as a new drug carrier, are defined as colloidal, opticallyisotropic, transparent or slightly opalescent formulations of low viscosity andthermodynamically stable dispersion system consisting of surfactant, co-surfactant, oiland water. Nanoemulsions present high solubilization capacity and bioavailabilityeven for poorly soluble drugs. Besides, nanoemulsions have good skin affinity, whichcan reduce the barrier function of stratum corneum. Nanoemulsions are useful asvehicles for transdermal drug delivery. Transdermal drug delivery, a convenientmethod of drug administration, enables physicians to provide controlled delivery ofdrugs to patients with minimal discomfort. Transdermal drug delivery offers manybenefits over delivery via the oral and injection routes, improves drug bioavailabilityand increases patient compliance. At the same time, nanoemulsion has sustainedrelease and targeting effect, which can make accurate positioning drugs on organs and tissues, release the drug slowly and achieve the best treatment effect.Based on pharmacological effects of ACADF and the characteristics of NE, thispaper designs and formulates ACADF nanoemulsion drug delivery system and hascarried on the quality evaluation. We studied the the drug targeting and mechanismof drug percutaneous absorption. We used pseudo-ternary phase diagram methods toscreen of surfactant, co-surfactant and oil phase and determine the optimalnanoemulsion formulation is （Tween80+Span80）/PEG400/IPM/water, km=1:1.Blank nanoemulsion appearance as a colloidal solution is clear and transparentbluish opalescent, drug-loaded nanoemulsion is brown transparent solution. Theaverage particle blank and drug-loaded nanoemulsion diameter were23.7nm and27.4nm; the Zeta potential of drug-loaded nanoemulsion is-6.5mV, pH value ofblank and drug-loaded nanoemulsion are5.8and6.0. The nanoemulsion presented assmall spherieal drops under SEM. Nanoemulsions remained stable state transparentand homogeneous after being centrifuged at high speed of10000r min-1for20min,5000lx strong light and high temperature of60℃. Drug-loaded nanoemulsion is stillclear, uniform and transparent, no delamination and precipitation phenomena, drugcontent had no obvious change within30days The mechanical stability, lightstability, thermal stability and long-term stability are good.The entrapment rate of92.35%and drug-loaded of2.16%are determined byHPLC, which has high recovery and precision. The targeting results in vivodemonstrated the passive targeting properties of nanoemulsions towards heart andkidneys organs. The penetration pathway of ACADF within the skin samples wasstudied using confocal laser scanning microscopy. The fluorescence signal of ACADFwithin the skin indicated that the absorption pathway of ACADF from thenanoemulsion includes both the follicular and transcellular routes. |
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