Implantable Microarray Patch: Engineering at the Nano and Macro Scale for Sustained Therapeutic Release via Synthetic Biodegradable Polymers

Abstract Transdermal drug delivery has been an increasingly studied alternative drug administration route owing to the large surface area of the skin, enabling ease of access and application. Among the various transdermal drug delivery technologies that have been developed so far, microarray patches (MAPs) incorporating microneedle technology (MN) have garnered much attention. MAPs can easily penetrate the stratum corneum , facilitating the delivery of desired substances directly into the skin, exhibiting a higher delivery efficiency compared to alternative transdermal drug delivery approaches. The effectiveness of MAPs in delivering therapeutics is affected by a multitude of factors, one of which is the selection of materials employed in their fabrication. Among various materials that have been used to fabricate MAPs, synthetic biodegradable polymers such as poly(lactic‐co‐glycolic acid) (PLGA) and polylactic acid (PLA) have been exploited for sustained and controlled release with excellent biocompatibility. PLGA and PLA can be used to construct the entire needle shaft or drug‐loaded microparticles which are then incorporated into needle layer. The combination of MN technology in conjunction with biodegradable polymers has revolutionized sustained and controlled transdermal delivery of small and large molecules.