Low Toxicity Of Amphiphilic Molecule System Phase Behavior And Application Research

Microstructure and dynamic rheological properties of lyotropic liquid crystalline phases andthe phase diagrams have been observed，with the aid of polarizing opficai microscopy andtheological techniques，for systems of oleyl polyoxyethylene ether (C_18：1E₂₀) with water andmixture system with a biology surfactant NaDC or a emulsion Tween80. In these investigations，varied special oil phase have been focused including pharmaceutically or food acceptedexcipients like isopmpyl myristate（IPM），butyl acetate and isoamyl acetate. As the supporter ofphase behavior the surface tension of AEO₂₀/Tween80 was determined by a Wilhelmy typesurface tension-meter. Then an application in sodium salicylate and curcumin delivery formed bylyotropic liquid crystal and microemusion has been investigation.All these results will enrich thesurfactant researches both theoretically and practically. In details, the thesis includes fivechapters as following:1. Applications of Amphiphilic Aggregates in Drug DeliveryThe rheological properties and drug carrier of micelle, microemulsions, lyotropic liquidcrystals and vesicle are easily summarized. This chapter describes the comprehensiveapplications as drug carrier of surfactant aggregate micelle, microemulsion, lyotropic liquidcrystals and vesicles used. The center of thesis is emphasized to the characterization of liquidcrystals and rheological properties further discuss the application as durg delivery.POE hasbecome an important component in the field of drug carrier. Then POE formed liquid crystal fortargeting drug system is reported relatively less.Therefore, as the mian properties of lyotropicliquid crystals in POE a nonionic surfactant oleyl polyoxyethylene ether (C_18：1E₂₀) which a kindof low toxic confusional and acceptable to the human body.On this basis, in the second, third andforth parts of the thesis, C_18：1E₂₀ternary or mixture systems of liquid crystallines containdifferent oils has been studied. And the release behaviour of sodium salicylate and curcumin inthe lyotropic liquid crystals and microemusion were measured by dialysis experiment in the fifthpart of the thesis. 2. Phase behavior of lyotropic liquid crystals formed by oleylpolyoxyethylene （20）ether C_18：1E₂₀/Oil/WaterIn this chapter, the phase diagrams of the ternary nonionic surfactant oleyl polyoxyethylene（20） ether / butyl acetate /water, oleyl polyoxyethylene （20） ether / isoamyl acetate /water,system was determined at 25℃. Two kinds of liquid crystal phase （H, V） were found in thesystem.Phase transform happen at the low concentration of the nonionic surfactant due toincrease the carbon atoms of oil. LLC phase were determined by TA-2000ex rheometer.The LLCphases show high elasticity as indicated by their mechanical and discrete relaxation spectra.Steady shear rheology results indicate that the LLC show shear-thinning behavior. Frequencydependence of experimental G′and G″were fitted using the multiple Maxwell model the cubicLLCs described by 3 Maxwell elements but with high modulus. Relaxation spectra of binarycubic monotone increase slightly. Ternary cubic has a lowest point at medium length ofrelaxation time.3. Molecule interaction in mixed micelle and phase behavior formed by oleylpolyoxyethylene （20） and Tween80 systemThe surface tension of Tween80/AEO₂₀was determined by a Wilhelmy type surfacetension-meter. The influence of temperature on equilibrium surface tension was studied. Theinteractions between the two surfactant molecules in mixed micelle were studied through surfaceactivity. Moreover Clint’s and Rubingh’s treatments were used to analyze the molecularinteraction parameters （β^m） and the molecule exchange energy（ε_m）. For systems investigated, itshowed that surface activity was advanced. At 25℃all mixtures showed synergism mostevidently, so study the phase behavior at 25℃.The result show the phase transformation areaand the rhreologcal properties is changed.4. Phase behavior of lyotropic liquid crystals formed by mixture systems ofAEO₂₀/NaDC The phase behavior, microstructure and rheological properties of were investigated byrheological techniques and polarizing optical microscopy in the presence of various additivesincluding NaDC, isoamyl acetate, butyl acetate, isopropyl myristate. Diagrams show that cubicphase transforms to hexagonal phase when decrease the length of oil tails. Steady rheologicalproperties indicate the theoretical exponent of the cubic LLC shows an exponent value between–0.77 and–1.17while the value of the hexagonal LLC range–0.60 to–1.51. The dynamicrheological properties inform the hexagonal phase is more close to liquid-like materials relativeto the cubic. Frequency dependence of experimental G′and G″were fitted using the multipleMaxwell model the cubic LLCs described by 3 Maxwell elements while hexagonal LLCsdescribed by 5 to 8 elements. NaDC weaken the moleculer reciprocity but improved the abilityof resisting shear rate.5. Drug Release Behavior of the Amphiphilic AggregatesDrug release behavior of the microemusion and lyotropic liquid crystals formed by nonionicsurfactant oleyl polyoxyethylene ether (C_18：1E₂₀). Study the effect of phase behavior caused bythe ethanol.When the weight is lower than 1/6 of the total weight, there are a small LLC phaseand large microemusion phase.The in vitro release behaviour of sodium salicylate and curcuminsolubilized in the microemusion were investigated via dialysis experiment at 25℃. Morecompare studying of the release of curcumin in Lyotropic liquid crystals with or without NaDCwas investigate. Invitro release showed that curcumin could be controlled release by the liquidcrystals .Curcumin could be protected by liquid crystals against sunshine. When NaDC added,the protection was better. The balance time of release was extended, when NaDC added.