Polymeric microneedles for controlled transdermal drug delivery

Polymeric microneedle (MN) systems are interesting transdermal drug delivery systems because of their controlled drug delivery, tunable properties, and ease of patient self-administration. They are biocompatible and can easily and painlessly penetrate the stratum corneum, delivering their contents into the dermis where they can be adsorbed into systemic circulation. Polymeric MNs can facilitate appropriate therapeutic dosing by controlling the release kinetics of pre-loaded drugs, targeting specific tissues, or responding to changing physiological conditions. This can be accomplished by modifying the degradation and swelling profiles of the host polymer and the diffusion profiles of the encapsulated drugs. In this review various mechanisms of controlled drug delivery using polymeric MNs, including new strategies, applications, and their future outlook are summarized and evaluated.