Buccal Drug Delivery System: Current Trends, Challenges, and Future Perspectives

Buccal drug delivery has emerged as an important approach within novel drug delivery systems, providing an alternative route for both local and systemic administration of therapeutic agents. Buccal administration reduces exposure of suitable drugs to gastrointestinal degradation and hepatic first-pass metabolism, thereby offering potential advantages over conventional oral delivery for selected drugs. This review discusses the fundamental aspects of buccal drug delivery systems, including the anatomy and physiological characteristics of the buccal mucosa, desirable characteristics, advantages and limitations, mechanisms of drug absorption, and factors influencing buccal permeation. Particular emphasis is placed on mucoadhesion and its underlying theories, polymer-related variables, environmental factors, and physiological factors that influence the performance of buccal formulations. Various dosage forms, including mucoadhesive tablets, patches, films, gels, and other emerging systems, are considered along with approaches such as permeation enhancement and enzyme inhibition to overcome barriers to effective drug absorption. Recent developments involving advanced buccal formulations and delivery technologies are also reviewed.