Recent advances in microneedle technology in transdermal drug delivery systems

INTRODUCTION: Transdermal drug delivery systems (TDDs) offer significant advantages over traditional drug administration routes (oral and parenteral); however, the barrier function of the stratum corneum limits its application to compounds possessing the obligatory physicochemical characteristics. To overcome the limitations of TDD, micro-sized needles can be used. Microneedles (MN), a non-invasive drug delivery system, can disrupt the skin's integrity, generating microchannels that facilitate the efficient infusion of drugs. AREAS COVERED: The review highlights the designing, (bio)materials utilized, classification, fabrication, optimization, and characterization of microneedles for TDDs application. The application of microneedles for vaccination, sustained transdermal delivery, biologics, targeted drug delivery, cosmetics, and advanced therapeutic applications are explored. The involvement of computational modeling and AI-driven approaches, 3D printing, etc. is included. The critical challenges in microneedle development, e.g., dimensional concerns, safety, adequacy, toxicity, scalability, regulatory, and sustainability, are also covered. EXPERT OPINION: Developments in the MN technology have extended the potential of the transdermal drug delivery system, holding potential to transform areas like immunization, chronic disease treatment, pain management, and real-time biomonitoring. In the upcoming decade, drug delivery procedures are expected to prioritize people's ease and self-supervision; however, supervisory synchronization, maneuver calibration, and sustained novelty will be indispensable for MNs to develop as a standard of care.