Effects of a novel orally-active antiallergic drug, quinotolast (FK021), on airway clearance

Abstract

The effects of a novel antiallergic drug, quinotolast (FK021, sodium 5-(4-oxo-1-phenoxy-4H-quinolizine-3-carboxamido) tetrazolate monohydrate), on airway clearance was studied in comparison with those of tranilast (an orally-active antiallergic drug). FK021 (10 mg/kg, p.o.) did not influence the rabbit airway secretion, whereas tranilast (100 mg/kg, p.o.) caused a slight suppression. Neither FK021 (10(-10)-10(-5) g/ml) nor tranilast (10(-6), 10(-4) g/ml) had any effect on pulmonary surfactant secretion in rat type II pneumocytes. FK021 (10 mg/kg, p.o.) caused a significant increase in the mucociliary transport rate in quails, whereas tranilast (320 mg/kg, p.o.) had no effect. Antitussive effects were examined in normal guinea pigs and guinea pigs made bronchitic by an exposure to SO2. FK021 (10 mg/kg, p.o.) and tranilast (320 mg/kg, p.o.) significantly depressed the cough reflex induced by citric acid in normal animals. FK021 (32 mg/kg, p.o.), but not tranilast (320 mg/kg, p.o.), showed antitussive effects on citric acid-induced cough in bronchitic animals. These results suggest that FK021 may have favorable effects on expectoration and cough reflex observed in the patients with chronic obstructive pulmonary diseases such as asthma.