ABSTRACT
To prepare the asiaticoside nanoemulsions (ASI-NEs) and asiaticoside nanoemulsions-based gels (ASI-NBGs), compare them with the commercial cream of asiaticoside (ASI-C) in terms of transdermal characteristics, and investigate the transdermal mechanism of ASI-NEs and ASI-NBGs. Their transdermal characteristics were studied by using Franz diffusion cells. The effect of topical ASI-NEs and ASI-NBGs on ultrastructure of rabbit skin was evaluated by using HE staining method. The localization and the permeation pathway of asiaticoside were visually investigated by using laser scanning confocal microscope (CLSM). The transdermal studies in vitro showed that the cumulative amount of ASI permeated from ASI-NEs and ASI-NBGs at 12 h after application were (3 504.30±180.93), (1 187.40±128.88) μg·cm⁻² respectively, 6.57, 2.23 times of that in the control group of ASI-C; the drug deposition of ASI-NEs and ASI-NBGs in skin was (159.48±7.47), (120.53±5.71) μg·cm⁻² respectively, 5.93, 4.48 times of that of ASI-C. HE staining of the rabbit skin after application of ASI-NEs and ASI-NBGs showed that the epidermis structure was basically intact; stratum corneum was loosed and the keratin fragment was increased; at the same time, the gap of prickle cell was increased and the basal cells were arranged loosely. The study of CLSM showed that significant percutaneous enhancer effect was observed for ASI-NEs after the topical application of 6 h, as the fluorescent compound was penetrated in the dermis and diffused uniformly. The fluorescence area and the integral optical density (IOD) were 28.81, 32.51 times of that in the FITC aqueous solution group, respectively. The fluorescent preparations showed strong fluorescence in the epidermis, but weak in deeper layers; with the increase of treatment time, the fluorescence in deeper layer was increased and stronger in skin appendages. The prepared ASI-NEs and ASI-NBGs have good transdermal characteristics and the transdermal mechanism is related to breaking the ultrastructure of stratum corneum and penetrating by the path of skin adnexa.
ABSTRACT
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.
ABSTRACT
It is a promising method to use Liposomes as a carrier in the transdermal delivery system.Presently,llposomes,deformable liposomes,and ethosomes are in common use.The transdermal mechanism of the liposomes is to promote the velocity and the amount of the drugs of transdermal absorbance by affecting the keratoderma,acting on the skin appendages and changing the exterior characteristic of the drugs to make them permeate the skins.The Mechanism of the actions includes hydration.penetration,transforamation,and osmotic pressure driving effect,etc.The liposomes have been approved to have abroad prospect of application in the transdermal delivery system.