6 - Microneedles for drug delivery and monitoring

Abstract

Microneedle (MN) arrays are a minimally invasive method of bypassing the stratum corneum barrier via piercing of the epidermis, creating reversible microscopic channels into the microcirculation. The concept of MN technology has developed significantly since its conception in 1976 and has been used to enhance topical and transdermal drug delivery, detect endogenous markers for patient monitoring and diagnosis, and improve the appearance of skin. Advantages of microneedles over a traditional hypodermic needle include a painless application, minimal skin trauma and bleeding, avoidance of needle phobia, potential for self-application, and a reduced risk of skin infection. The advancement of MN technology has seen the fabrication of arrays from a range of materials and the development of several types of needles, most notably solid, hollow, coated, dissolving, and hydrogel microneedles. Each type is associated with its own advantages and has been utilized for delivery of specific compounds. For example, dissolving microneedles have been explored in the realm of vaccine delivery, as there results in no sharp disposal waste following application, and the ability to self-administer needles could result in widespread vaccine coverage in low resource settings, where there may be shortages of medical personnel. This chapter focuses on the use of MN arrays for drug delivery and patient monitoring, illustrating the wide ranging capabilities of this technology.