Clinical Translation of Microneedles for Diabetes Drug Delivery and Metabolic Monitoring

Microneedles provide access to skin for peptide delivery and metabolic sensing, but insertion alone does not establish reliable treatment. This narrative review examines the evidence linking microneedle design to clinical claims in diabetes and identifies requirements for translation. Targeted literature retrieval distinguishes human delivery and sensing studies from animal and analytical experiments. Human hollow-microneedle studies show faster insulin absorption than subcutaneous administration, although improvement in primary glycemic outcomes is inconsistent. Responsive insulin and glucagon patches, incretin depots, and integrated sensing–delivery systems remain predominantly preclinical. Human sensing studies provide quantitative feasibility data, but accuracy depends on calibration, reference methods, population, and wear duration. We assess bioactive deposited dose separately from nominal loading, prospective decision accuracy separately from analytical agreement, and commanded delivery separately from verified exposure. Application mechanics, residual drug, local interference, manufacturing, and usability inform a proposed validation framework mapped to relevant standards and regulatory documents. This mapping is conceptual and does not constitute regulatory validation. The review identifies product-specific experiments needed to establish reproducible exposure, dependable measurements, and benefit against appropriate comparators. It does not infer human effectiveness from animal glucose lowering or assign one development pathway to all microneedle architectures.