Polymers-based devices for dermal and transdermal delivery

The skin is the largest organ of our body and represents a unique barrier that protects us from external agents (Hadgraft 2004). It is made up of three main layers, the epidermis (divided into the stratum corneum and the viable epidermis), the dermis, and the hypodermis. In particular, the stratum corneum is characterized by a thickness of 10–20 μm and contains between 10 and 15 layers of corneocytes, which are continually removed and regenerated, while the viable epidermis consists of multiple layers of keratinocytes at various stages of differentiation.