1.9 Bioavailability

FLASHCARDS – Bioavailability

Flashcard 1
Q: Define bioavailability (F).
A: The proportion of an administered drug that reaches systemic circulation in active form.

Flashcard 2
Q: What is the bioavailability of IV drugs?
A: 100%.

Flashcard 3
Q: Name two main factors that lower oral drug bioavailability.
A: Incomplete absorption and first-pass metabolism.

Flashcard 4
Q: How does lipid solubility affect absorption?
A: Lipid-soluble drugs cross membranes more easily, increasing absorption.

Flashcard 5
Q: Give an example of a factor in the stomach that can affect absorption.
A: Antacids changing pH.

Flashcard 6
Q: What does F = 0.21 mean?
A: 21% of the administered dose reaches systemic circulation.

Flashcard 7
Q: In Example 1, with 500 mg dose and F = 0.45, how much reaches systemic circulation?
A: 225 mg.

Flashcard 8
Q: In Example 1, how much drug was not absorbed?
A: 178.6 mg.

Flashcard 9
Q: In Example 2, with 110 mg dose, F = 0.21, and 37% excreted, how much was metabolised?
A: 46.2 mg.

Flashcard 10
Q: Why can’t you solve for absorbed, metabolised, and excreted amounts if two are unknown?
A: Because there’s insufficient data; one unknown is the limit for calculation.