Sublabial Strips: An Emerging Approach for Transmucosal Drug Delivery

Sublabial strips have emerged as advanced mucoadhesive polymeric platforms designed for efficient transmucosal drug delivery. These thin flexible films are administered between the upper lip and gingival mucosa where they rapidly hydrate and release the incorporated drug either immediately or in a controlled manner. Sublabial delivery bypasses hepatic first-pass metabolism and minimizes gastrointestinal degradation, thereby enhancing systemic bioavailability and therapeutic efficacy. The present review highlights the anatomy of oral mucosa, mechanism of drug permeation, formulation components, manufacturing techniques, evaluation parameters, therapeutic applications, recent advancements, and future perspectives associated with sublabial strip technology. Various preparation techniques including solvent casting, hot melt extrusion, electrospinning, and rolling methods have been critically discussed along with their advantages and limitations. Recent investigations involving nanotechnology, smart polymers, nanofiber systems, and AI-assisted formulation strategies have further expanded the pharmaceutical potential of sublabial strips. Despite several advantages, challenges such as moisture sensitivity, limited drug loading capacity, scale-up difficulties, and packaging instability continue to restrict commercialization. Nevertheless, continuous advancements in pharmaceutical technology may establish sublabial strips as promising next-generation patient-centric drug delivery systems.