Study On The Preparation And Antibacterial Properties Of Antibacterial Liquid Cubic Phase Based On Glyceryl Monooleate

Objective:It is planned to load palmatine and nano silver into glyceryl monooleate-based cubic phase respectively to prepare antibacterial gels capable of long-term release and pH-responsive release.Method:(1)The aqueous solution of palmatine was characterized by UV-Vis;nano silver were prepared by reduction method and characterized by TEM,UV-Vis and DLS.(2)The liquid cubic phase containing palmatine were prepared by absorbing water from the melted mixture of glycerol monooleate and palmatine;The nano silver loaded liquid cubic phase were prepared by absorbing water from the mixture of melt monooleate / CTAB / Ag NP.(3)Characterization of antibacterial cubic phase: the microstructure was observed by TEM;The structure changes with temperature through microscopic examination by PLM;The heating endothermic curve is observed through DSC.(4)The medium diffusion was used to qualitative characterize the antibacterial properties of antibacterial cubic phase against S.aureus and E.coli;the quantitative analysis of in vitro release further clarified the dissolution properties of palmatine and nano silver.Result:(1)By preparing aqueous solutions of different concentrations of palmatine,the ultraviolet-visible absorption spectrum at 200-800 nm was measured,and the absorbance at 342 nm was selected to establish a standard curve of palmatine concentration-absorbance;The uniformly dispersed nano silver suspension was prepared by the reduction method in water,The nearly spherical and uniformly dispersed nano silver particles with the particle size of 10-20 nm were observed under the TEM,The hydrated particle size of nano silver measured by DLS is about 70-80 nm,and the potential of the surface measured by Zeta electrode is-50 m V.(2)The palmatine-loaded GMO gel was prepared by blending method:Gel(2.5%w)、Gel(1.0%w)、Gel(0.25%w)、Gel(0.10%w)、Gel(2.5%o)、Gel(1.0%o)、Gel(0.25%o)、Gel(0.10%o);With the aid of CTAB,nano silver was loaded into the cubic phase,and the molar ratio of CTAB to silver ranged from 2 / 0 to 2 / 1.(3)Characterization of the cubic phase containing palmatine: Under the TEM,both the aqueous phase and the lipid phase encapsulated palmatine exhibited a crystal layer structure.The cubic phase loaded with palmatine were characterized by PLM and DSC,and it was found that the addition of palmatine had no significant effect on the phase transition of cubic phase.Characterization of cubic phase with nano silver: From the TEM,CTAB can promote the uniform dispersion of nano silver in the crystal layer of the cubic phase without affecting the crystal layer structure.By PLM and DSC to characterize the nano silver-loaded cubic phase,it was found that the addition of CTAB and nano-silver did not significantly affect the phase transition of the cubic phase.(4)In vitro release and bacteriostatic properties of the cubic phase loaded with palmatine: in PBS buffer solution,the release rates of palmatine in gel(2.5% w),gel(1.0% w)、gel(0.25% w)、gel(0.10% w);gel(2.5% o)、gel(1.0% o)、gel(0.25%o)、gel(0.10% o)were 36%、32%、28%、18%;52%、40%、22%、12%.However,the control group Ctrl(2.5%w)、Ctrl(1.0%w)、Ctrl(0.25%w)、Ctrl(0.10%w);Ctrl(2.5%o)、Ctrl(1.0%o)、Ctrl(0.25%o)、Ctrl(0.10%o)at 4h release rate reached 72%、73%、73%、75%;72%、72%、75%、78% and remained unchanged.The results showed that the entrapment of palmatine into the cubic phase could prevent the sudden release of palmatine and prolong the release period of palmatine to 7 days.In the medium diffusion test,the size of the inhibition zone of palmatine-loaded cubic phase to S.aureus and E.coli increased with the increase of concentration,and the solution group was significantly larger than that of the cubic liquid crystal group.Antibacterial properties and in vitro release of nano silver-loaded cubic phase:the medium diffusion test confirmed that nano silver-loaded cubic phase could release silver and had antibacterial effects on E.coli and S.aureus,and the size of the antibacterial zone increased with the increasing amount of nano silver in cubic phase.The release rate of silver from the Gel(2/1)group of cubic phase was 13.0%at pH 3.0,which was much higher than that from the same group of cubic phase at pH 5.0 and 7.4(3.8% and 0.1%,respectively).Conclusion:(1)Pamatine was successfully loaded into glyceryl monooleate cubic phase.After loaded into cubic crystal,it can prevent the sudden release of palmatine and prolong the release period to 7 days.Moreover,it has a good bacteriostatic effect on S.aureus and E.coli.This property can make up for the problem of unstable release and high concentration of palmatine tablets and is expected to be used in the field of drug loading.(2)Nano silver was successfully loaded into lipid phase of the cubic liquid crystal,and the prepared cubic phase had an enhanced bacteriostatic effect on S.aureus and E.coli with the increase of the concentration of nano silver.Moreover,the release of silver nanoparticles was in accordance with the pH response,and could be significantly released when the pH was 3.0.Cubic phase shows potential application value in the direction of stimulus-responsive antibacterial carriers.