Chapter 3 - Transdermal drug delivery via microneedle patches

Abstract

Transdermal drug delivery systems using noninvasive or minimally invasive technology are an important part of novel drug delivery systems. Among the different minimally invasive delivery approaches, transdermal delivery via microneedles (MNs) has garnered considerable attention in recent years, particularly for protein and vaccine delivery to treat diseases such as diabetes or cancer. The MNs are three-dimensional microstructures with lengths usually less than 1000μm. The MNs can be designed with different needle lengths to reach appropriate depth without hurting nerves in the underlying dermis and damaging blood vessels. As such, MNs can be used to transcutaneously deliver both hydrophilic and hydrophobic drugs and biomolecules, effectively overcoming this limitation of conventional transdermal drug delivery. Metallic MNs have been fabricated as the first generation of microneedles for transdermal use. However, the low drug-loading capability, potential breakup in the skin, and costly fabrication methods have greatly limited their clinical application. To overcome these issues, polymers have been used to fabricate advanced MNs for drug delivery application. Previous studies have demonstrated that MN can successfully deliver both low and high molecular weight drugs for the treatment of a variety of diseases. This chapter summarizes the recent strategies which have been used for the development of polymeric microneedles for the treatment of diabetes and cancer, which are the two leading lethal diseases in humans.