ABSTRACT
The shortcomings of oral drug delivery and the pain associated with hypodermic needles have shifted the drug delivery orientation toward the transdermal route. This chapter focuses on the history, types, mechanisms, and applications of drug delivery, along with the recent innovations in microneedle drug delivery systems. It highlights the delivery of different therapeutic agents efficiently via microneedles of various designs and compositions, ultimately showing the potential role of microneedles as a transdermal drug delivery system. There are two major factors determining the mechanism of delivery via microneedles: mechanical disruption of the skin and release of the drug or vaccine within the epidermis layer. Microneedles need to be stored under conditions that maintain drug activity and ensure microneedle integrity, like sharpness, strength, and sterility. Microneedles can be used for needle-free delivery of anesthetics. As they are minimally invasive in nature, cause no pain, and are small in size (100 microns), they play a major role in drug delivery.
