Intrinsic clearance Clint is defined as the organ's inherent ability to clear drug independent of blood flow.

• A. Clint is the liver's inherent ability to clear drug independent of blood flow.
• B. Clint is the hepatic blood flow.
• C. Clint is the fraction unbound fu.
• D. Clint is the Vd.

Answer: (A)

Intrinsic clearance is about the organ’s enzymatic ability to metabolize a drug when delivery to the organ isn’t limiting. For the liver, Clint captures that inherent capacity to clear drug, independent of how much blood is flowing to the organ. In other words, Clint reflects how fast the liver’s drug-metabolizing enzymes can work on the drug, assuming access to the enzymes isn’t restricted by blood flow. The hepatic blood flow would limit clearance in flow-limited situations, fraction unbound fu affects how much drug is actually available for metabolism in vivo, and the volume of distribution relates to how the drug is distributed in the body, not how quickly it’s cleared.