Microneedles for drug delivery: recent advances in materials and geometry for preclinical and clinical studies

INTRODUCTION A microneedle array patch (MAP) has been studied as a means for delivering drugs or vaccines and has shown superior delivery efficiency compared to the conventional transdermal drug delivery system (TDD). Because the effectiveness of a MAP depends on the materials with which it is made, its size, and its shape, many researchers have designed a variety of MAPs. This paper reviews recent advancements in the development of MAPs, with a focus on their size, shapes, and materials in preclinical and clinical studies for pharmaceutics. AREA COVERED We classified MAPs for drug delivery into four types: coated, dissolving, separable, and swellable. We covered their recent developments in materials and geometry in preclinical and clinical studies. We tried to determine how these factors could affect the strategies and efficacy of drug delivery. EXPERT OPINION The MAP is an excellent drug delivery system that has provided desirable pharmacokinetics and pharmacodynamics in many studies. Its functions and strategies can be influenced by the geometry of microneedles as well as the materials from which it is constructed. Therefore, the design of MAPs needs to be determined based on what properties would be effective for the target diseases and purposes. In addition, in preclinical studies, it is necessary to consider not only the novelty of the formulations, but also the feasibility of clinical application. Currently, clinical studies of microneedles loaded with various drugs and vaccines are in progress. When the regulation of pharmaceutical microneedles is established and more clinical studies are published, more drugs will be developed as microneedle products and clinical research will proceed. With these considerations, the microneedle array patch will be a better option for drug delivery.