Microporation Using Microneedle Arrays

Abstract

In order to exploit the transdermal route for systemic delivery of a wide range of drug molecules including peptide/protein molecules and genetic material, a means of disrupting the excellent barrier properties of the uppermost layer of the skin, the stratum corneum, must be sought. The use of microneedle (MN) arrays has been proposed as a method to temporarily disrupt the barrier function of the skin and thus enable enhanced transdermal drug delivery. MN arrays consist of a plurality of micron-sized needles, generally ranging from 100 to 3000 μm in height, of a variety of different shapes and composition (e.g. silicon, metal, sugars and biodegradable polymers). The application of such MN arrays to the skin results in the creation of aqueous channels which are orders of magnitude larger than molecular dimensions and, therefore, should readily permit the transport of macromolecules. MNs are sufficiently long to disrupt the stratum corneum but have sufficiently shallow penetration to avoid bleeding and pain. This chapter will focus on the recent and future developments for MN technology, focusing on the materials used for MN fabrication, the forces required for MN insertion and the potential safety aspects that may be involved with the use of MN devices.