The skin compliance of transdermal drug delivery systems.

This review examines transdermal drug delivery systems (TDS) and focuses on the specific side effects they can have on the skin and how these may be avoided. After a general overview of the structure of skin and its functions, an outline is given of how TDS are composed and how they operate. Upon basic treatment of relevant skin irritation and sensitization phenomena, techniques are described for monitoring them. Subsequently, various specific skin reactions are dealt with; these can be evoked by TDS on both short- and long-term application. Suggestions are then put forward for improving the skin compliance of TDS. For example, it is proposed that hydrogel patches may prove to be a useful alternative for current systems in that they are suitable for long-term applications, having minimal side effects because they are less occlusive.