KAPS Pharmacokinetics and Biopharmaceutics 3

Question 1

Which route of administration MOST effectively avoids first-pass hepatic metabolism?

Accepted Answer

Sublingual tablet

Answer

Sublingual administration allows drugs to be absorbed directly through the oral mucosa into systemic circulation, completely bypassing the GI tract and hepatic first-pass effect.

Question 2

Why is the protein binding of a drug clinically significant?

Accepted Answer

Only the free (unbound) drug fraction is pharmacologically active and available for distribution

Answer

Only free (unbound) drug can cross membranes, interact with receptors, be metabolized, and be excreted; protein-bound drug acts as an inactive reservoir.

Question 3

Which formulation strategy would MOST effectively increase the oral bioavailability of a poorly water-soluble drug (BCS Class II)?

Accepted Answer

Micronization to reduce particle size

Answer

Micronization increases the surface area of drug particles, which enhances dissolution rate and thereby improves oral bioavailability for poorly soluble drugs.

Question 4

Enterohepatic recirculation refers to:

Accepted Answer

Drug cycling between the intestine and liver via biliary excretion followed by intestinal reabsorption

Answer

Enterohepatic recirculation occurs when drug or its metabolites excreted into bile are reabsorbed from the intestine, prolonging the drug's half-life and duration of action.

Question 5

The Henderson-Hasselbalch equation is MOST useful in pharmacokinetics for predicting:

Accepted Answer

The degree of ionization of a drug at a given pH

Answer

The Henderson-Hasselbalch equation (pH = pKa + log[A⁻]/[HA]) predicts the ionization state of a drug at any given pH, which directly governs membrane permeability and absorption.

(KAPS) Knowledge Assessment of Pharmaceutical Sciences Practice Test

(KAPS) Knowledge Assessment of Pharmaceutical Sciences Practice Test

KAPS Pharmacokinetics and Biopharmaceutics 3