Enhanced transdermal delivery of 18β-glycyrrhetic acid via elastic vesicles: in vitro and in vivo evaluation

Objective: The aim of this work was to develop an elastic vesicular formulation to enhance the skin permeation of a poorly water-soluble 18 beta-glycyrrhetic acid (GA) and treat dermatitis. Methods: Elastic vesicles of GA were prepared by the film method with high pressure homogenizer and characterized by storage stability. In vitro permeation studies were carried on rat skin using Franz diffusion cell. In vivo skin deposition of GA was studied using HPLC assay. Chronic allergic contact dermatitis model was built to evaluate pharmacodynamic of GA elastic vesicles. Results: The GA elastic vesicles developed have high flexibility and the storage stability was at least for 6 months at 4 degrees C and for 4 months at 25 degrees C. In vitro cumulative penetration of GA from elastic vesicles within 8 hours was 5.3-fold and 23.2-fold higher than that of conventional liposomes and saturated solution, respectively. After non-occlusive application to mice ears in vivo, skin deposition of GA increased immediately and reached the C-max at 3 h (1.95 +/- 0.32 mu g/cm(2)) and still detected, even after 16 hours GA removed. In vivo anti-inflammatory activity study, GA elastic vesicles showed significant reduction in ear thickness and mass (25.52% and 49.23%) (P < 0.05). The suppressive activity was comparable to that of positive control group (Triamcinolone Acetonide and Econazole Nitrate cream in market), while few side effects were observed in present model. Conclusion: The results suggested that of GA elastic vesicular was safe and effective in treatment of contact dermatitis by transdermal administration.