A Review on Current Status and Future Potential of Transdermal Patches as a Promising Drug Delivery System

Transdermal patches are now widely used in topical and transdermal drug delivery systems (TDDS). Up to now, TDDS has been used in several conditions, such as smoking cessation, analgesic effect, nausea, contraception, and hormone therapy. Basically, there are two types of transdermal patches: the reservoir-type patches and the matrix-type patches. First generation TDDS were designed for delivery of drugs in low-dose. In second-generation delivery systems, drug penetration was increased using chemical enhancers and iontophoresis. Several methods such as microneedles, electroporation, and cavitational ultrasound are used as the third generation of TDDS for targeting their effects to skin’s barrier layer of stratum corneum. Microneedles are currently studied through clinical trials as suitable delivery system for macromolecules and vaccines, such as insulin and influenza vaccine. This review article describes the structure of different types of transdermal patches and some marketed products. It also introduces a framework for present and future developments of percutaneous drug delivery by transdermal patches.