Hydrogel‐Forming Microneedle Arrays for Enhanced Transdermal Drug Delivery

TLDR

Microneedle arrays made from crosslinked polymers that contain no drug themselves are described. They rapidly absorb skin interstitial fluid upon insertion, forming continuous, unblockable hydrogel conduits that link patch‑type drug reservoirs to the dermal microcirculation. These microneedles can be fabricated in diverse patch sizes and geometries, sterilized easily, resist hole closure, and be removed intact; they enable macromolecule delivery independent of microneedle loading, with transdermal transport governed by hydrogel crosslink density and allowing electrically modulated release, thereby overcoming conventional microneedle limitations and expanding the range of deliverable drugs for industry, healthcare, and patients.

Abstract

Abstract Unique microneedle arrays prepared from crosslinked polymers, which contain no drug themselves, are described. They rapidly take up skin interstitial fluid upon skin insertion to form continuous, unblockable, hydrogel conduits from attached patch‐type drug reservoirs to the dermal microcirculation. Importantly, such microneedles, which can be fabricated in a wide range of patch sizes and microneedle geometries, can be easily sterilized, resist hole closure while in place, and are removed completely intact from the skin. Delivery of macromolecules is no longer limited to what can be loaded into the microneedles themselves and transdermal drug delivery is now controlled by the crosslink density of the hydrogel system rather than the stratum corneum, while electrically modulated delivery is also a unique feature. This technology has the potential to overcome the limitations of conventional microneedle designs and greatly increase the range of the type of drug that is deliverable transdermally, with ensuing benefits for industry, healthcare providers and, ultimately, patients.