Absorption, Distribution and Excretion of the Tritium-Labelled β2 Stimulator Fenoterol Hydrobromide Following Aerosol Administration and Instillation into the Bronchial Tree

Abstract

The administration by aerosol of fenoterol hydrobromide (Berotec) [used in asthma therapy] was investigated in 4 test persons. Two patients with operable carcinomas of the lung were given 3H-labeled fenoterol hydrobromide aerosol immediately before undergoing surgery. Parts of the pulmonary segments removed were biochemically analyzed and it was observed that the radioactive contents in pulmonary tissue and blood plasma were almost identical. The pharmacokinetic data recorded after aerosol administration, i.e., plasma levels and renal excretion, are not different from those recorded after oral administration. The expired air following aerosol administration was examined in 2 patients, whereby less than 0.1% of the dose administered was recovered. The oropharynx was found to contain 53% of the dose immediately after administration. Absorption via the lungs was examined in 4 other test persons by instilling an aqueous solution of fenoterol hydrobromide into the right bronchial tree. Comparison of renal excretion levels showed that absorption here is greater than after oral administration; the plasma level curves, however, run a very similar course.