In a crossover bioavailability study, a tablet formulation gives an area under the plasma concentration-time curve (AUC) of 80 mg.h/L, while the same dose given intravenously gives an AUC of 100 mg.h/L. The absolute oral bioavailability of the tablet is:

• A 20 percent
• B 80 percent ✓
• C 100 percent
• D 125 percent

Explanation

Absolute bioavailability F equals AUC oral divided by AUC intravenous, adjusted for dose if doses differ. Here F = 80/100 = 0.8, meaning 80 percent of the dose reaches the systemic circulation intact. Option A represents the fractional loss, not bioavailability, and option D inverts the ratio. Intravenous dosing defines the reference because it delivers 100 percent of the dose systemically.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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