Question

Bioavailability refers to _______

• A. Rate and extent of drug reaching systemic circulation
• B. Drug protein binding
• C. Drug metabolism
• D. Drug excretion

Hint:

Bioavailability tells how much and how fast a drug reaches systemic circulation.

Answer 1

The Correct Option is A

Concept:
Bioavailability is an important pharmacokinetic parameter. It tells how much drug reaches the systemic circulation in active form.

Step 1: When a drug is administered, it must be absorbed into the blood to produce systemic effect.

Step 2: The amount of drug that reaches systemic circulation is called the extent of absorption.

Step 3: How fast the drug reaches systemic circulation is called the rate of absorption.

Step 4: Bioavailability includes both rate and extent of drug absorption.

Step 5: Therefore, bioavailability refers to the rate and extent of drug reaching systemic circulation. \[ \boxed{\text{Rate and extent of drug reaching systemic circulation}} \]