Construction And Properties Of Ordered Aggregations Encapsulated Polyphenols

Polyphenols contain flavonoid,astragalus,phenolic acid and lignan.Flavonoid including curcumin,dihydromyricetin and apigenin had abundant pharmacological activity such as anti-bacteria,anti-inflammation,anticancer and antioxidation.However,the poor solubility and stability of polyphenol severely hindered its practical application.This thesis studied drug carriers based on surfactant for encapsulating polyphenols.Lyotropic liquid crystal and emulsion gel were constructed to encapsulated polyphenol.The relationship between composition and viscoelasticity of drug carriers through rheological experiment.Release behaviors of polyphenols were studied through simulating in vitro release experiment.Antioxidation experiment were carried out to study scavenging properties of drug carriers encapsulated polyphenol.The main work listed as follows.In earlier stage of the thesis,many literatures related to lyotropic liquid crystals as drug carrier were searched and reviewed.Lyotropic liquid crystals were easy to prepared and had controllable structures.Lyotropic liquid crystals could protect drugs and had a solubilizing effect on drugs.Lyotropic liquid crystals could reinforce stability of drugs.Therefore,lyotropic liquid crystals were chose as the main content to study.In chapter two,surfactant aggregations encapsulated dihydromyricetin were prepared based on GMO-Span80/Et OL/H₂O system.Rheological experiment showed that elastic moduli of samples were larger than viscous moduli,which indicated that the elastic properties of samples were better than viscous properties.Samples showed shear-thinning phenomenon.With the increase of H₂O content in samples,the release rate of dihydromyricetin showed decreasing trend in turn.Therefore,samples with more H₂O content have better sustained release properties.Samples encapsulated dihydromyricetin exhibited better scavenging properties to DPPH than dihydromyricetin.In chapter three,lyotropic liquid crystals were prepared in GMO-Brij98/PG/H₂O system.Rheological properties of liquid crystals which have different compositions were studied.For samples with the same surfactant content,samples with more PG/H₂O have largerσ_c.This indicated that samples had more stable structure.The viscous moduli of samples at first increased and reached a maximum value in nonlinear viscoelastic region.And then the viscous moduli rapidly decreased.This phenomenon was attributed to the formation of a weak intermediate structure partly due to hydrogen bonding.Release behaviors of liquid crystals respectively encapsulated curcumin,dihydromyricetin and tea polyphenol were studied.Curcumin showed evidently larger release rate compared with DMY and TP.First order kinetic model was the most appropriate kinetic model to release data,indicating that the in vitro release of polyphenol from samples was controlled by concentration diffusion.The antioxidant properties of curcumin LCNPs and DMY LCNPs were studied.Experiment results showed that the IC₅₀ of polyphenol loaded LCNPs was an order magnitude smaller than polyphenol.This indicated polyphenol loaded LCNPs had better scavenging properties.Moreover,DMY LCNPs had better scavenging properties than curcumin LCNPs.This may be due to the possibility that more free hydrogen formed in DMY LCNPs.In chapter four,emulsion gels used as drug carrier for curcumin were prepared in GMO-Brij98/IA/H₂O/GG system.Water holding capacity experiment showed the water holding percentage of emulsion gel was at least 92%,which indicated that emulsion gels have nice water holding capacity.In vitro release experiment showed that curcumin exhibited smaller release rate in samples with more GG content.This may be due to the possibility that samples with more GG content have more stable structure.Curcumin exhibited faster release rate from samples in larger pH.Release behaviors of curcumin from samples in which GG combined with different polysaccharides including soluble starch and glucan were studied.Curcumin showed faster release rate and higher cumulative release percentage from samples in which GG combined with different polysaccharides.First order kinetic model was the most appropriate kinetic model to release data,indicating that the in vitro release of curcumin from emulsion gels was controlled by concentration diffusion.In chapter five,lyotropic liquid crystals and microemulsion were prepared in Brij97-EPE/IPM-PEG400/H₂O system at 37 ℃.Samples with different compositions were prepared through Brij97 combining with different EPE.Release behaviors of curcumin from samples with different compositions were studied.The release curve of curcumin in sample prepared by Brij97 combining with F68 was the lowest to reach the release platform.Curcumin showed faster release rate and higher cumulative release percentage from samples in which Brij97 combined with L81 and F68 respectively when adding Na DC or gleditsin in water phase.Microemulsion encapsulated curcumin showed better scavenging properties than curcumin.Samples prepared by adding Na DC or gleditsin in water phase resulted in smaller IC₅₀,which indicated that adding Na DC or gleditsin in water phase could strengthen the scavenging properties of curcumin loaded microemulsion.