Phenazone metabolism during perfusion of isolated guinea pig liver

After 3 hr of perfusion of isolated guinea pig liver with a medium containing 407 ng/ml of phenazone, the drug concentration in the bile was 1.5 times higher than the initial concentration in the perfusion fluid. This indicates that in addition to phenazone metabolism, liver eliminates the drug by active releasing it to the bile. The active release is responsible for depression of phenazone concentration during the perfusion in approx. 6%. The remaining loss of phenazone is due to its hepatic metabolism.