Effect of vehicles on topical application of aloe vera and arnica montana components

In this work two types of gel and microemulsions were investigated for their ability to dissolve Helenalin, a flavonoid responsible of anti-inflammatory activity of Arnica Montana extract and Aloin, an anthrone-C-glucosyls with antibacterial activity present in Aloe Vera extract. The release of these agents from each vehicle was followed by HPLC and transcutaneous absorption was examined using a modified Franz cell. The study evidenced that a microemulsion can be considered as good vehicles to increase permeation of helenalin, while the gel formulation containing Sepigel 305 as emulsifier demonstrated able to reduce release and permeation of aloin with a consequent surface activity, without any permeation, in accord with the view that the human skin fibroblasts can metabolise absorbed aloin into a structurally related compound that increases the sensitivity of skin to UV light.