[A study on maximal permissible drug concentration for transnasal medication from the viewpoint of ciliary activity of the cultured human paranasal mucosa].

Aerosol therapy has been widely used for upper and lower airway diseases. However, maximal permissible concentrations of drugs have not yet been clarified. The purpose of this study was to find the maximal drug concentration for transnasal medication that does not inhibit ciliary activity or tissue. Human paranasal sinus mucosa taken at surgery was cut into small pieces. These were cultured in RPMI-1640 medium under the conditions of 5% CO2 and 100% relative humidity at 37 degrees C. Histopathologic damage was observed under a microscope at 400 x magnification. The rate of ciliary beating was measured by a photoelectric method with a cadmium sulphite photometer. In order to compare the findings with those of repeated clinical nebulizer therapy, drug application once a day for 3 days and combined use with steroids were examined for 30 min, considering maximal retention time of the drugs in the nasal cavity as an aerosol therapy. The maximal permissible concentrations of several drugs in single use obtained by these experiments were as follows: acetylcysteine 4.4%, tyloxapol 0.03%, sodium cromoglycate 4%, Broncasma Berna 2 times, prednisolone 1%, dexamethasone 0.2%, betamethasone 0.4%, kanamycin 20%, gentamicine 1%, amikasine 4%, dibekasin 4%, astromysin 4%, fosfomycin 3%, clindamycin 3%, ampicillin 10%, cefazolin 5%, and lidocaine 0.01%. When antibiotics and ateroids were used at the same time, the ciliary activity and the tissue were damaged more strongly than with single use. Therefore, the maximal concentration of some drugs has to be reduced. For example, the maximal concentration of prednisolone, 1%, was reduced to 0.2%, and that of kanamycin, 20%, was changed to 10%.