FIG. 2

The relation of hepatic extraction ratio (x axis) to maximum bioavailability of a drug after oral dosage (y axis) for a drug whose clearance is due entirely to hepatic biotransformation. Extraction ratio (ER) is calculated as the ratio of clearance after intravenous dosage divided by hepatic blood flow. Oral bioavailability (F) cannot exceed the quantity 1-ER.

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published 2000