Recent advances in intraoral, buccal and sublingual drug delivery systems and technologies.

Oral transmucosal drug delivery has emerged as a powerful alternative to conventional oral administration by enabling rapid drug absorption, avoiding hepatic first-pass metabolism, and improving bioavailability and patient compliance. Recent advances in pharmaceutical technology have led to the development of a wide range of oral/mucosal dosage forms, including fast-dissolving films, buccal tablets and patches, semisolid formulations, and nanotechnology-enabled delivery systems. This critical work provides a thorough account of the physiological barriers of the oral mucosa and the advances in drug formulations designed to enhance active pharmaceutical ingredients (APIs) solubility, stability, muco-, cyto- and bioadhesion, and mucosal permeation. Recent clinical developments and commercially available products are presented to highlight translational challenges and opportunities. In addition, we address the integration of emerging technologies, such as electrospinning/electrospraying, three-dimensional printing for personalized medicine and artificial intelligence for predictive optimization of critical quality attributes. Collectively, these advances underscore the growing potential of oral transmucosal platforms, as versatile and patient-centred drug delivery systems for next-generation pharmaceutical applications.