Microneedles for transdermal drug delivery: a minireview.

The stratum corneum is the main barrier for transdermal drug transport. It could be bypassed by microneedles, which have a length of a few tens to a few hundreds of microns. They are usually arranged in arrays and can be used in several ways to enhance transdermal drug transport. Microneedles can be inserted into the skin in order to increase its permeability, after which the drug is applied (poke with patch). Drugs could also be coated onto the microneedles and be inserted into the skin (coat and poke). Hollow microneedles are used to inject drug solutions in to the skin. This review aims to discuss recently published in vivo and in vitro studies on microneedle aided transdermal drug delivery.