Characteristics, preparation and applicability in oral delivery systems of cellulose ether-based buccal films

With the rapid development of buccal films (BFs), the demand for film-forming materials and preparation techniques has increased. Cellulose ethers (CEs) exhibit favorable properties, such as effective film formation, mucosal adhesion, and biocompatibility; as such, they are most commonly employed as film-forming materials, essential for BF fabrication. CE-based BFs, classified as orodispersible and buccal mucoadhesive films, can be prepared through solvent casting, inkjet printing, three-dimensional printing, electrospinning, and hot melt extrusion. Hydrophilic CE-based orodispersible films can rapidly dissolve or disintegrate upon contact with saliva to release drugs. High-viscosity or hydrophobic CEs can serve as protective layers for BFs, controlling the unidirectional release of drugs and mitigating the effects of saliva and buccal movements. These mucoadhesive films can firmly adhere to the buccal mucosa for an extended period, prolonging drug release time and enhancing bioavailability. CEs come in various types and grades, exhibiting different rheological and physicomechanical properties, which also provide options for customized design to specific patients. This review provides an overview of CE-based BF technology, analyzes the challenges and development directions of this film, and identifies key areas for scientific research, such as the interactions of bioadhesive materials in buccal mucosal drug delivery. The objectives of this review are to (i) highlight the value of their application in oral drug delivery and (ii) promote the broader adoption of BF-based patient-centric dosing.