Disposition of a new steroidal anti-inflammatory agent, deflazacort, in rat, dog and man

The physiological disposition of a new steroid anti-inflammatory agent, deflazacort, was examined in rat, dog and man following 5 mg/kg doses to the animals, and 50 mg to humans. The administered radiocarbon [2′-14C]- deflazacort), is rapidly and extensively absorbed into the general circulation in rat and man, whereas the bioavailability in the dog is low. The terminal plasma half-life for radioactivity elimination was, on the average, 11,15 and 28 hr in rats, dogs and man, respectively. Urinary exretion was the predominant route of14C elimination in the rat (−54% of the dose) and in man (−68% of the dose), whereas in the dog the majority of the dose was eliminated via the feces (82%). Tissue distribution studies in the rat did not show target organs, with the exception of the blood cells. Studies of binding to plasma proteins of the 21-desacetyl deflazacort, demonstrate in all the species a rather low level of binding of non-saturable type.