RESUMO
Objective: To prepare nanoemulsions (NE) and nanoemulsion-based gels (NBGs) with Sophora flavescens alkaloids (SFA) as model drug to illuminate its mechanism of transdermal delivery basically. Methods: Using scanning electron microscopy (SEM) method, HE staining method, and confocal laser scanning microscope (CLSM) method to investigate the effect of SFA-NEs and SFA-NBGs on stratum corneum (SC) and ultrastructure. Results: The results of SEM showed that the SC of normal mouse was smooth and finishing. And slightly crimp the saline group after 6 h of treatment appeared, while it was damaged in varying degrees hurt after 2 h and 6 h of action by SFA-NEs and SFA-NBGs, respectively. HE staining results indicated that the skin structure of saline group was basically intact. But the hierarchy structure of SFA-NBGs group was not obvious, basal layer arranged unclearly and SC loosed apparently, as well as that the hierarchy structure of SFA-NEs group disordered, the gap increased, SC loosed and thinned. The result of confocal laser scanning microscope indicated that fluorescence in surface was stronger while weaker in depth among control group, SFA-NEs group, and SFA-NBGs group, and fluorescence in hair follicles and around its appendages was also stronger. Conclusion: SFA-NEs and SFA-NBGs could permeate skin mainly through breaking SC and ultrastructure so as to perform therapeutic action. At the same time, hair follicles and its appendages play a role on drug transdermal course.