A new method for evaluating mucolytic expectorant activity and its application. I. Methodology.

: A new method for evaluating in vivo effect of mucolytic expectorants was devised. In this report, however, the focus is placed on methodology but not on pharmacology. Rabbits with subacute bronchitis were prepared by long-term exposure to minute amounts of SO2 gas. The sputum was quantitatively collected from the animal through a tracheal cannula at suitable time intervals according to the Perry and Boyd's method. As a preliminary study, changes in volume, viscosity and amounts of freeze-dried substance of sputa were examined after intraduodenal administration of water instead of mucolytic expectorants, the effects of which will be described in the subsequent paper, but no significant changes occurred with this test.