Oral drug delivery mucus barrier

The function of the mucosal pellicle is to serve as a barrier between the oral epithelial surface and the external environment, and so it may also act as a barrier to drug delivery. However, there are limited studies assessing the role of the mucus layer in buccal permeability. In one study, treatment of the oral mucosa with anticholinergic agents resulted in an increased permeability of certain compounds, and it was suggested that the reduced salivary flow may have been responsible for the reduced barrier properties of the tissue [113]. In... 

Upon intranasal administration, a drug is not as susceptible to dilution and first-pass effects as in oral delivery.46 47 The nasal route may also be an effective means of delivering drugs to the brain 46 Barriers to nasal delivery include the enzymes of the nasal mucosa, the epithelial barrier, the mucus layer, and limited absorption time resulting from mucociliary clearance.48... 

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