Nasal drug absorption metabolism studies

Although this section deals mainly with the advantages of excised tissues with respect to nasal drug delivery studies, it is important to highlight some important attributes of nasal in situ perfusion model. Although this method does not provide data on systemic absorption, it enables study of the interactions of nasal mucosal enzymes, peptide substrates, and metabolic inhibitors and their implications for nasal drug absorption [13], It also enables the rate of nasal drug absorption to be determined. 

Cultured nasal cells are reliable models for drug transport and metabolism studies, since they are known to express important biological features (e.g. tight junctions, mucin secretion, cilia, and various transporters), resembling those found in vivo systems. Moreover, easy control of experimental conditions as well as separation of the permeation step from the subsequent absorption cascade is also possible. A relatively simple primary culture condition using human nasal epithelial cells for in vitro drug transport studies has been established and applied in transport and metabolism studies of drugs. It is known that the culture condition and/or selection of culture media are critical in the recapitulation of well-differentiation features of in vivo nasal mucosal epithelium [46],... 

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