Nasal epithelium permeability increase

Morimoto et al. [33] demonstrated that the ocular absorption of hydrophilic compounds over a wide range of molecular weights could be increased by 2 and 10 mM sodium taurocholate and sodium taurodeoxycholate in a dose-dependent manner. The compounds were glutathione (307 Da), 6-carboxyfluorescein (376 Da), FTTC-dextran (4 kDa), and insulin (5.7 kDa). Of the two bile salts, sodium taurodeoxycholate was more effective. At 10 mM, this bile salt increased the permeability of 6-carboxyfluorescein from 0.02% to 11%, glutathione from 0.08% to 6%, FITC-dextran from 0% to 0.07%, and insulin from 0.06% to 3.8%. Sodium taurocholate, on the other hand, increased the permeability to 0.13%, 0.38%, 0.0011%, and 0.14%, respectively. Taurodeoxycholate was more effective than taurocholate in the nasal epithelium as well [202], This difference in activities can possibly be attributed to their micelle-forming capability, which is higher for taurodeoxycholate, a dihydroxy bile salt [190],... 

A variety of molecules have been studied in an effort to find a compound which is able to increase the permeability of the nasal epithelium without causing harm (Table 9.5). 

List the mechanisms by which the permeability of the nasal epithelium may be increased to improve the efficacy of nasal drag delivery. 

Ohtake, K. Maeno, T. Ueda, H. Natsume, H. Morimoto, Y. Poly-L-arginine predominantly increases the paracellular permeability of hydrophilic macromolecules across rabbit nasal epithelium in vitro. Pharm. Res. 2003,20 (2), 153-160. 

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