Foetoplacental drug clearance in the rabbit: Studies with trimazosin, acebutolol and tolmesoxide

1. An animal model suitable for studying placental extraction of large numbers of drugs without the need for major surgical facilities, has been developed in the anaesthetized New Zealand white rabbit with sampling of both arterial and venous blood of the foetoplacental unit.2. Three drugs with different routes of metabolism were studied: trimazosin, tolmesoxide and acebutolol. There was no extraction across the foetoplacental unit.3. The clearance of acebutolol differed significantly in rabbits from different suppliers.4. These results do not suggest a role for the placenta in drug metabolism. They do, however, suggest a previously undescribed genetic determinant of acebutolol metabolism.