Physicochemical Characterization of Lecithin/Isopropyl Myristate Reverse Micelles

摘要

Reverse micelles have good thermodynamic stability, small particle size, good self-assembly performance, and controlled drug release versus other microparticle transdermal drug delivery systems. Here, a reverse micelles solution and a gel system formed by self-assembly of insulin aqueous solution/ lecithin/isopropyl myristate (IPM) were used for transdermal delivery of insulin. The size, size distribution, morphology and rheology of the reverse micelles were characterized with dynamic light scattering (DLS), small angle x-ray scattering (SAXS), differential scanning calorimetry (DSC), viscosity measurement, and freeze fracture transmission electron microscopy (FF-TEM). The findings suggested that lecithin/isopropyl myristate self-assembled reverse micelles were spherical with uniform particle sizes (< 100 nm). The water in the reverse micelle was in the form of bound water, and the diameter of the water pool was about 4 nm. The reverse micelle solution and gel appeared as a pseudo-plastic fluid. The gel was thixotropic, which benefits transdermal delivery.