KAPS Pharmacokinetics and Biopharmaceutics 2

Question 1

Which statement about first-order drug elimination kinetics is TRUE?

Accepted Answer

A constant fraction of the drug present is eliminated per unit time

Answer

The absolute amount of drug eliminated per unit time is constant

Answer

The elimination rate is independent of plasma concentration

Answer

First-order kinetics only occur at very high drug concentrations

Question 2

Drug clearance is BEST defined as:

Accepted Answer

The volume of plasma completely cleared of drug per unit time

Answer

The fraction of drug excreted unchanged in urine

Answer

The time required for plasma concentration to decrease by 50%

Answer

The fraction of drug bound to plasma proteins

Question 3

Which equation correctly describes the relationship between elimination half-life (t½), volume of distribution (Vd), and clearance (Cl)?

Accepted Answer

t½ = 0.693 × Vd / Cl

Answer

t½ = Vd × Cl / 0.693

Answer

t½ = Cl / (0.693 × Vd)

Answer

t½ = 0.693 × Cl × Vd

Question 4

Which pharmacokinetic parameter is MOST useful for comparing total drug exposure between different dosing regimens or formulations?

Accepted Answer

Area under the plasma concentration-time curve (AUC)

Answer

Peak concentration (Cmax)

Answer

Time to peak concentration (Tmax)

Answer

Elimination half-life

Question 5

A drug has 25% oral bioavailability. If the desired IV dose is 80 mg, what approximate oral dose is needed to achieve equivalent systemic exposure?

Accepted Answer

320 mg

Answer

20 mg

Answer

80 mg

Answer

160 mg

Question 6

The Biopharmaceutics Classification System (BCS) categorizes drugs based on which two properties?

Accepted Answer

Aqueous solubility and intestinal permeability

Answer

Molecular weight and charge

Answer

Protein binding and lipophilicity

Answer

Half-life and volume of distribution

Question 7

Steady-state plasma concentration is typically achieved after approximately how many half-lives of continuous dosing?

Accepted Answer

4–5 half-lives

Answer

1–2 half-lives

Answer

2–3 half-lives

Answer

8–10 half-lives