[Biological determination of the beta blocking activity of human serum]. / Détermination biologique du pouvoir bêta-bloquant du sérum humain.

ABSTRACT

A method of biological assessment of the Beta blocking activity of human serum is reported. It is based on the catecholamine response of rat myocardial cells in culture, incubated in the serum to be tested. Its advantage is that it takes into account all block-blocking substances present in the serum, not only the drug itself but also its possible active metabolites. The results obtained by this method in 10 healthy subjects after 60 mg penbutolol were compared with those given by chemical dosage and ergometry. The ergometric and biological changes were parallel from the 2nd and the 8th hour while the serum levels of the drug rapidly. This discordance could be due to the presence of an active metabolite, 4-hydroxy-penbutolol.