Action of several β‐adrenoceptor blocking drugs in the pregnant sheep and foetus

Abstract

The effect of several β‐adrenoceptor blocking drugs on the pregnant ewe and foetus were studied. Bunolol, butidrine, oxprenolol, propranolol and USVP65‐24 all crossed the ovine placenta and produced a β‐adrenoceptor blockade in the ovine foetus. AH3474, AY21011 and sotalol did not cross the ovine placenta as assessed by the absence of a β‐blockade in the foetus when these compounds were administered to the pregnant ewe. Of the β‐blocking compounds tested, only propranolol and oxprenolol produced a prolonged blockade in the foetus. The β‐blockade with propranolol was of 3 h duration in the ewe and 10 h duration in the foetus. Oxprenolol produced a β‐blockade of 3 h duration in the ewe and 8 h in the foetus. The β‐blocking drugs which did cross the ovine placenta were more soluble in organic solvents (ether, chloroform, corn oil and olive oil) than those which did not cross the ovine placenta. 1973 British Pharmacological Society