Pharmacokinetics and cardiopulmonary effects in dogs of sublingual pirbuterol, a new bronchodilator.

The time course of plasma concentrations of sublingually administered pirbuterol was investigated in anesthetized dogs; there was a dose-related increase in plasma drug concentrations which reached maximum values 1 hr or more after administration. In a second study plasma drug levels were correlated with antagonism of histamine-induced changes in pulmonary compliance and resistance which also reached maximum values 1 hr or more after drug administration, although marked antagonism was apparent at 15 to 30 min; blood pressure was unaltered at any dose level and heart rate was influenced only at the highest dose level. A convenient method for study of the bioavailability of sublingual formulations is described, and the potential usefulness of a sublingual dosage form of pirbuterol is discussed.