A New Experimental Method for Evaluating Drugs in the Nasal Cavity

A new experimental method permits evaluation of nasal decongestant activity in anesthetized rats and guinea pigs on spontaneous nasal resistance, histamine-induced congestion, and experimental allergic rhinitis. This method can detect decongestant activity of known standards at clinically effective concentrations and may also differentiate decongestant drugs with different durations of action. This method also permits testing of drugs administered into nasal cavities, a clear advantage over other currently used methods. Dose responses were obtained for phenylephrine hydrochloride, oxymetazoline hydrochloride, and pyrilamine maleate on spontaneous nasal resistance. Surface active agents appeared to enhance decongestant activity of phenylephrine hydrochloride. Acetylcysteine, a mucolytic, also reduced spontaneous nasal resistance. Pyrilamine maleate and phenylephrine hydrochloride both prevented histamine-induced congestion, and pyrilamine maleate antagonized allergically-induced increase in nasal resistance.