Haumshchild and Haumshchild (31) argued that there was a close relationship between the inflammation that occurs within the oral cavity and the general health of the oral cavity. Moreover, the authors ascertained that periodontal disease was linked to systemic disease development and that systemic diseases had an overall impact on oral health. Sander et al. (38) stated that the ease in the accessibility of the oral cavity was one of the reasons for its preference as a drug delivery route alongside the targeted local treatment of oral diseases. The oral cavity is described as a complex system colonised by many microorganisms (47). Moreover, oral cavities can be associated with systemic health and oral health, whereas changes in many factors can result in the shift of oral microbiota composition, thereby causing oral diseases (47).
Liang, Peng, Zhou, Zou, and Cheng (48) ascertained that the mucoadhesion concept was introduced in the early 1980s and has been associated with buccal drug delivery as a drug administration route. Patel, Dhagash, Patel and Chaudhry (12) added that mucoadhesions were shown to prolong the dosage forms’ retention time at the application site for the effective delivery of these agents. Moreover, the close contact and retention time of the mucoadhesions with mucous membranes and absorption tissues allows for the improved therapeutic drug performance, both systemically and locally (12). Scarpa et al. (13) noted that the advantages of oral cavities as drug delivery routes were attributed to the direct and rapid onset of action locally (13). Moreover, Sánchez, Ruiz, Castán, and Morales (14) added that drugs undergoing hepatic clearance and gastrointestinal degradation for patients who have difficulties in swallowing could be easily delivered to their target sites via the oral cavity.