Polymeric Membrane-Based Systems in Transdermal Drug Delivery

Controlled drug delivery systems (CDDSs) are increasingly attracting interest from the scientific community in order to achieve highly precise, customized, and efficient therapeutic treatment of various diseases. The challenge is to develop highly innovative devices and appropriate administration methods in order to reduce side effects and further improve patient compliance. In this context, transdermal drug delivery systems (TDDSs) represent smart tools that permit supplying therapeutically effective amounts of drugs at a fixed time using the skin as the administration route. They are non-invasive and allow for avoiding gastric side effects and first-pass metabolism occurring in the liver. TDDSs have been produced using numerous therapeutic agents and, more recently, also biological molecules. However, it must be highlighted that they are complex systems, and their formulation requires a multidisciplinary approach and expertise in polymer chemistry and materials science. A contribution in this direction is given from the integration of membrane technology with biological and pharmaceutical sciences. The present review deals with a general overview of controlled drug delivery systems. Particular attention is devoted to TDDSs and to the materials used for producing polymeric membrane-based TDDSs with a membrane engineering perspective. It also describes the passive and the most advanced active strategies for transdermal delivery. Finally, different transdermal membrane-based release systems, like patches, mixed-matrix membranes, and imprinted membranes are discussed.