Diaplacental Transfer Study in Rats

To obtain information about the distribution of a drug and/or its bio transformation products in dams and fetuses in dependence of time. 

9 healthy female 18 days pregnant Sprague Dawley rats weighing about 300 g (approximately 12 weeks old) receive the radiolabeled compound the route of administration projected to be used therapeutically (for oral or intravenous administration to rats and animal maintenance see the procedure described in the rat mass balance study). 

3 animals/time point are killed painlessly (CO2 anesthesia, exsanguination as described in the blood/plasma radiokinetic study in rats ) and are each immediately dissected. 

The rat is placed in a dorsal position on an undersheet and the fur is moistened with ethanol/water. The abdominal cavity is opened and the abdominal wall folded back. The uterus is exposed and the amniotic fluid is withdrawn by puncturing the amniotic sac with a syringe. The uterus is then placed on a plastic film and opened. The placentas with the fetuses are detached from the uterus. The placentas are then detached from the fetuses. After removing the fetal membranes the fetuses are removed and immediately killed under CO2 atmosphere. The amniotic fluid is aspirated with a disposable syringe. 

The organs and tissues listed below are removed. The number of fetuses is determined and documented. The fetuses per dam and their organs, respectively, are pooled. The order of removal is prescribed in the following dissection schedule. 

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