Mucosa tablet adhesion

Jimenez-Castellanos et al. developed a method to measure both the adhesional and frictional forces involved in the attachment of such tablets to mucosa. These researchers found that a good correlation existed between the maximal adhesion strength and polymer content of the tablets tested [155]. 

Adhesive tablets are more user-friendly than eonventional tablets and allow drinking and talking without mueh diseomfort. Some of the disadvantages include inflexibility, a rather small surfaee area for eontaet with the bueeal mucosa, and on demand, drug delivery carmot be aeeelerated [53]. 

Sustained adhesion of the dosage form (tablet, patch) to the mucosa is an important first step to successful buccal delivery. The mucus plays an important role during this mucoadhe-sive process by buccal drug delivery systems. The interaction between the mucus and mucoadhesive polymers generally used in most dosage forms can be explained by theories summarized in Table 9.1. 

The strength of mucoadhesion of the tablets was quantified based on the tensile force required to break the adhesive bond between a model membrane, i.e., porcine buccal mucosa and the test pol5mier. The study revealed that locust bean gum and chitosan in a weight ratio of 2 3 not only releases the drug unidirectionally from the dosage form, but also results in buccal tablets which are sufficiently mucoadhesive for clinical applications (34). 

Figure 4J3 Schematic events following bioadhesion of a matrix tablet at a mucosal surface (a) initial contact of the dry polymeric matrix with the mucosal surface (b) polymeric chains are progressively hydrated at the matrix surface and in contact with the mucous layer lining the mucosa (c) progressive chain interdiffusion between bioadhesive polymer chains and mucous glycoproteins encourages intimate contact and favours development of adhesive interactions, schematically depicted as black spots at the molecular level.

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