Pickering Emulsion With Antibacterial And Anti-inflammatory Activity

Bacterial infection and inflammation will disrupt the process of skin wound healing,therefore,antibacterial and anti-inflammatory play a vital role in this course.The matrix of commercial ointment is mostly hydrocarbons and lipids,such as paraffin,beeswax and lanolin,which has no antibacterial and anti-inflammatory effect.In recent years,Pickering emulsion（PE）stabilized by natural biodegradable particles has attracted extensive attention,it avoids the hemolytic,irritating reaction and toxicity accumulation related to surfactants.Meanwhile,the multicomponent system enables PE to be loaded with multiple substances to improve their effects.Vitamin E（VE）,tea tree oil,chitosan（CS）and gum arabic（GA）have antibacterial and anti-inflammatory effects which have a positive effect on wound healing.Therefore,PE prepared with chitosan/gum arabic nanoparticles（CS/GA NPs）,tea tree oil and VE for wound healing has expanded the application of PE in the field of pharmacy.（1）CS/GA NPs were prepared and tested by Fourier infrared spectroscopy（FT-IR）,transmission electron microscopy（TEM）,contact angle and particle size.The results showed that CS/GA NPs formed mainly through electrostatic interaction are irregular oval or spherical;The particle size is 81.96±11.63 nm and the contact angle is89.85±0.18°when the concentration of CS/GA NPs is 1.5%and the ratio of CS and GA is 1:1 and,which has the greatest effect on the formation of stable emulsion.The preparation process of PE was optimized.Investigated the effects of the concentration,proportion and oil-water ratio of CS and GA on the stability of PE by single factor test and orthogonal test.The optimum formula is as follows:the concentration of CS/GA NPs is 1.5%,the ratio of CS and GA is 1:1,and the proportion of oil phase is 40%.（2）Through the study on the properties,identification,inspection and content determination of PE loaded VE（VE-PE）,the quality standard system has been preliminarily formed.①The product is a uniform milky white opaque liquid under the optimal prescription.②The test sample VE in PE has the maximum absorption at 282 nm by UV spectrophotometry.③The protective effect of PE system on VE and the storage stability of PE were investigated.The DPPH method confirmed that VE retains its antioxidation in the PE preparation process;Moreover,an improved UV irradiation stability was observed for the VE after being encapsulated in the PE;The PE also shows good storage stability since there was no obvious change in its diameter（from 352.2±10.43 nm to 563.9±21.17 nm）,morphology of emulsion droplets and p H after storage at 4℃,25℃,40℃ for 30 days.④The content of VE was determined by UV spectrophotometry.The methodology was investigated by recovery and repeatability test,the established method had good reproducibility,accuracy and reliability.The encapsulation efficiency was 94.54%±0.62 and the loading content was 0.1872%±0.009.（3）The pharmacodynamics of VE-PE was carried out.The study of release kinetics in vitro found that VE in PE conformed to the first-order model,and the whole release process more accorded with the sustained-release.The bacteriostatic effect of PE on S.aureus,E.coli,P.aeruginosa and C.albicans showed that the PE group is better than that of classical emulsion（CE）,CS/GA NPs and tea tree oil.In the acute inflammation model of mice with increased peritoneal permeability induced by acetic acid,the inhibition rates of Evans blue exudation in the medium dose group(M_VE-PE)and high dose group(H_VE-PE)of VE-PE are 64.13%and 81.48%respectively,indicating that VE-PE has a certain acute anti-inflammatory effect.The wound healing experiment showed that PE,CE,CS/GA NPs and tea tree oil has curative effects on wound healing,and PE has the best therapeutic effect.