Lamellar Liquid Crystals Formed by Pharmaceutically Accepted Brij97 Surfactant

摘要

Lamellar liquid crystals of Brij 97 aqueous solutions were investigated by means of SAXS and rheological techniques at 25 ℃, when adding varied additives including IPM, oleic acid, ionic liquid bmim-PF6 and bmim-BF4. All the lamellar phases show high elasticity indicated by their mechanical and discrete relaxation spectra, which can be expected to be an advantage as drug delivery vehicles. In addition, to compare with other systems, the lamellar phase formed in Brij 97/water/IPM system has the largest molecule interfacial area and the lowest storage and loss moduli, implying its weak network strength and less stable internal structure. Moreover, Brij 97/water/ bmim-PF6 system exhibits fluid-like viscoelastic property to some extent. These differences are analyzed through SAXS data as the different location of the additive in the lamellar phase, in which oleic acid is principally penetrated between the surfactant molecules to participate the formation of the interfacial layer, while bmim-BF4 and bmim-PF6 are mainly located in the hydrophilic domain and IPM is solubilized in the nonpolar area of the lamellar structures.