Liposomes: a novel topical delivery system for pharmaceutical and cosmetic applications.

This review will highlight work done in our laboratories evaluating topical liposomal delivery in a wide variety of animal models and human skin using both in vivo and in vitro techniques. The mechanism by which liposomes facilitate deposition of drugs into the skin and some potential applications of topically applied liposomes will be discussed. Particular emphasis will be placed on the development of analytical techniques that allow the quantification of drug levels in the various skin strata and in pilosebaceous structures. Appropriate models of skin representing the two cases, as well as those wherein both routes are available for skin deposition, were examined using a wide variety of liposomal preparations containing radiolabeled and fluorescent molecules as marker compounds.