SURFACTANTS AND EXPERIMENTAL IRRITANT CONTACT-DERMATITIS

Surface-active agents (surfactants) are characterized by the possessio n of 2 different moieties, both polar and non-polar regions on the sam e molecule. Surfactants are broadly classified as anionic, cationic, a mphoteric, or non-ionic, according to the nature of the hydrophile yie lded in aqueous solution. In currently marketed household, personal, a nd industrial cleaners, anionic surfactants are the most common class because of their relative ability to solubilize fats and oils, lower t he surface tension of aqueous solutions, or form microemulsions. Many surfactants elicit irritant reactions when applied to the skin, partia lly due to their relative ability to solubilize lipid membranes. Hence , surfactants have become important implements in skin irritation inve stigations. In general, the physicochemical properties of surfactants are a crucial factor in eliciting skill irritation. Anionic surfactant s are broadly accepted as potent irritants to human and animal skin. C ationic surfactants are reputedly at least equally irritating, but mor e cytotoxic than anionic, while the irritation potential of non-ionic surfactants is considered the lowest. Such classification of innumerab le surfactants is convenient and held in high practical esteem. Howeve r, the categorization does not permit the exact determination of irrit ation and cytotoxicity potential of each surfactant. Ranking of surfac tant skin irritancy and cytotoxicity obtained by both in vitro and in vivo assays provides a helpful orientation for future work.