[The absence of stereoselectivity in propranolol uptake by the lungs]

Propranolol (P) is known to be actively captured by the lungs of experimental animal and man. To elucidate the mechanism of the phenomenon, the authors studied the P enantiomeric ratio in the serum from the left ventricle 0-10, 10-20 and 20-30 s after bolus injection of P (0.5 mg) into the pulmonary artery of 8 patients catheterized for coronary angiography. The total P concentrations and enantiomeric ratio were measured by non-stereoselective and stereoselective high performance liquid chromatography. The solid-phase extraction method was used for extracting P from the serum. It showed a small, but significant increase is S(-)/R(+) ratio (to 1.18 +/- 0.12, P < 0.05 vs 1) which was, however, almost the same when measuring this after adding P to serum of the same patients (1.11 +/- 0.05, P > 0.05 vs 1.18). Thus, propranolol uptake by the lung during a single passage is not stereoselective and hardly involves some active process.