Nasal mucosa blood supply

In comparison to the skin, the buccal mucosa offers higher permeability and faster onset of drug delivery, whereas the key features which help it score over the other mucosal route, the nasal delivery system, include robustness, ease of use, and avoidance of drug metabolism and degradation. The buccal mucosa and the skin have similar structures with multiple cell layers at different degrees of maturation. The buccal mucosa, however, lacks the intercellular lamellar bilayer structure found in the stratum corneum, and hence is more permeable. An additional factor contributing to the enhanced permeability is the rich blood supply in the... 

As discussed above, the nasal mucosa is highly vascular. This property facilitates its physiological role in heat exchange and also potentially, drug absorption. The rich blood supply means that drags absorbed via the nasal route have a rapid onset of action, which can be exploited for therapeutic gain. 

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