Targeted delivery to the pilosebaceous unit via liposomes

The significance of the pilosebaceous unit (hair follicle and sebaceous glands) as a route for passive drug delivery into the skin remains a controversial subject. The pilosebaceous unit is a complex, dynamic structure, which is the site of unique biochemical, metabolical and immunological events. Recent topical delivery studies have employed increasingly systematic, quantitative methodologies in attempts to define the follicular pathway. Targeting specific sites of the hair follicle may represent a feasible therapeutic approach, as several dermatological abnormalities are known to originate at the hair follicle. In a growing number of topical delivery studies, liposomes have been shown to target drug delivery to the pilosebaceous unit. This review will describe general aspects of follicular delivery, with a particular focus an studies which have demonstrated targeted follicular delivery via liposomes.