Metabolism of chlormadinone acetate in the human and in laboratory animals. (Abstract only)

The metabolism of tritium-labeled chlormadinone acetate has been studied after oral and iv administration to human subjects and after iv administration only to female beagle dogs and female rhesus monkeys. Plasma half life of free (solvent estractable) radioactivity (after the iv dose) varied considerably from 1 species to another being 33-38 hours in the dog 21-22 hours in the monkey and 3-4 hours in the human Similarly the total volume of distribution Vd expressed in liters/kg body weight was greater in the dog (13 and 143 1/kg) as contrasted to the monkey (5.2-6.8/kg) and the human (2.3-3.3 l/kg). Another major difference between the dog on the one hand and the human and the monkey on the other was the mode of excretion over a period of 168 hours. The dog excreted only 8-9% of the administered radioactivity in the urine and 33-46% in the feces; whereas over a comparable period of time the monkey excreted 35-36% in the urine and 26-28% in the feces. The human excretory pattern was simlar to that seen in the monkey. The results will be discussed in terms of advisablity of using the dog as an experimental animal to provide a guide to human studies. In addition other aspects of chlormadinone acetate metabolism will be described.(Full text)