Mucolytic agents and mucociliary activity

The three substances bromhexine, NA 872 (bromhexine metabolite VIII) and the beta 2-receptor agonist NAB 365 (clenbuterol) and their effect on the mucociliary activity have been studied in vivo in rabbits. The substances were given parenterally in increasing dosages and 519 records were obtained from 12 rabbits. Not even at dosages in excess of recommended human dosages has any effect on the mucociliary activity been observed for any of the substances during the first 30 minutes after administration. The conclusion to be drawn is that the three substances have no effect on the mucociliary activity in rabbit in vivo, but that this does not exclude an effect on mucociliary transport or clearance.