| Summary: | 碩士 === 國立成功大學 === 化學工程學系碩博士班 === 101 === A carrier for enhancing skin delivery of drugs had been discovered and named ‘‘ethosome,’’ which was phospholipid vesicular system embodying ethanol in relatively high concentrations. This work aimed at developing competent ethosome-like catanionic vesicles for dermal drug delivery. Three kinds of lipid-like ion-pair-amphiphiles, IPAs, were prepared by the precipitation method. They were DeTMA-DS, DeTMA-TS and DTMA-DS, respectively, and were thereafter used as the new raw materials to prepare the ethosome-like catanionic vesicles with the aid of ethanol as the cosolvent in aqueous buffer solution whose pH value was 7.4 by a simple semispontaneous process. In addition, the potential applications of the catanionic vesicles as nano-carriers in dermal drug delivery were demonstrated by the encapsulation of vitamin E acetate (α-tocopherol acetate, α-TA) and used a kind of water-soluble polymer with hydrophobic modification as a thickener to improve the viscosity of vesicular dispersion.
The experimental results revealed that the vesicle stability could be enhanced by the addition of cholesterol. The bilayer membrane phase transition temperatures of three kinds of IPAs were detected via DSC. Cooperating with the results of fluorescence polarization analysis, we find that the bilayer membrane rigidity for DeTMA-DS and DeTMA-TS systems with relatively lower phase transition temperatures increased with the addition of cholesterol. On the other hand, the bilayer membrane rigidity for DTMA-DS system with relatively higher phase transition temperatures slightly decreased with the addition of cholesterol. Moreover, the encapsulation efficiency and released rate of Vitamin E acetate positively and negatively, respectively, correlated to the bilayer membrane rigidity. Finally, analyze the rheological properties by dynamic rheometer to study the hydrophobic interaction between vesicles and polymers. The more rigid bilayer membrane resulted in the stronger hydrophobic interactions, indicating that the more rigid bilayer membrane possessed the stronger bilayer hydrophobicity as well as the higher encapsulation efficiency. As to the driving force of releasing drug might be the concentration gradient of Vitamin E acetate. The more rigid bilayer membrane could hinder the diffusion of drugs and result in the lower released rate.
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