The development and registration of topical pharmaceuticals.

From our own experience we have seen that over the past 60 years topical delivery of drugs with its advantages and disadvantages has become much more widely understood and much more is now known about the disposition of drugs in the skin. Today, pharmaceutical scientists produce dermatological vehicles which are tailored to patients' needs and better appreciate how the formulation may affect rates of drug delivery, and ultimately, efficacy and safety. The guidelines for developing a New Chemical Entity (NCE) to be administered by the topical route are rather straightforward. What appears to be less well understood are the pathways for development, and the regulatory routes for topical formulations of a known established Active Pharmaceutical Ingredient (API) either in a new formulation, at a different concentration, or with APIs where topical administration is an alternative route of administration. This article provides guidance, on the regulatory routes which can help achieve marketing approval in Europe for topical formulations, with particular emphasis on clinical development. Some comments on NCE's will be given, and further detail is provided in cases where the topical route is a new method of administration for delivering a known API.