Preparation And Evaluation Of Glabridin Ethosome Gels

Purpose:In this paper,the flavonoids of the poorly water-soluble traditional Chinese medicine,glabridin,was prepared into ethosome,in order to improve its solubility and improve its biological activity.The glabridin ethosome was further prepared into a gel,which provide ideas and reference for the study of skin drug preparations for poorly soluble traditional Chinese medicine.Methods:The glabridin ethosome were prepared by injection-ultrasound bonding method.The particle size,potential,encapsulation efficiency,drug loading and so on were used as indicators to optimize the formulation process of glabridin ethosome.Determination of glabridin ethosome formation were characterized by appearance、DLS、TEM,etc,and the drug content,stability,release,etc.were evaluated;the inhibition of tyrosinase activity and antioxidant activity of glabridin ethosome and their safety were preliminary studed.The glabridin ethosome were further prepared into a gelling agent,and the drug content,release rate,and skin irritation of the glabridin ethosome gel were investigated.Results:Ethanol,propylene glycol,mixed alcohol(propylene glycol:ethanol=8 v:2v)and appropriate amount of phospholipids,water,and 0.01%SDS were added as the prescription to prepare the glabridin ethosome.The obtained empty ethosome were light blue translucent,and the glabridin ethosome were yellow translucent liquid.The particle size were 30～60 nm,and the distribution were relatively uniform,and the potential were less than-25 m V,which were stable.Ethosome were phospholipid bilayer structure.The encapsulation efficiency of ethanol ethosome,propylene glycol ethosome and mixed alcohol ethosome were 91.47%,87.33%,and 91.39%,respectively,and the drug loading were 2.46%,1.77%,and 2.41%,respectively.Compared with its suspension,the ethosome can significantly slow down the release rate of the drug,with sustained release characteristics.Biochemical method showed that the inhibition rate of tyrosinase activity by ethanol ethosome,propylene glycol ethosome and mixed alcohol ethosome were 24.27%,23.32%and 17.93%higher than that of glabridin suspension.It showed that the inhibition rate of tyrosinase activity of ethanol ethosome,propylene glycol ethosome and mixed alcohol ethosome were38.07%,19.58%and 40.42%higher than that of glabridin suspension in B16-OVA cells.The reductive power of three kinds of glabridin ethosome to the potassium ferricyanide were also higher than that of the suspension.Confocal electron microscopy showed that B16-OVA cells consumed more coumarin 6 ethosome than coumarin 6 suspensions.Human epidermal cytotoxicity and rat skin irritation results showed that glabridin ethosome was safer.The glabridin ethosome were further prepared into gel using Carbomer 940.The contents of glabridin in ethanol ethosome gel,propylene glycol ethosome gel and mixed alcohol ethosome gel were 643.09,414.79 and 615.08μg/g,respectively.The cumulative release of gel at 12 h were 11.11,7.03,6.30μg/cm~2,which were consistent with the release law of ethosome,indicating that the release behavior of glabridin was not changed after the preparation of the ethosome into gel.The glabridin ethosome d gel were less irritating to the skin of rats and safer.Conclusions:In this paper,the glabridin ethosome and their gels were successfully prepared,which improved the water solubility of glabridin,and improved the antioxidant activity and tyrosinase activity inhibition of glabridin,and the safety was good.