DHA Pharmacist Pharmaceutical Sciences

Question 1

Which pharmacokinetic parameter describes the fraction of an administered drug dose that reaches systemic circulation unchanged?

Accepted Answer

Bioavailability (F)

Answer

Bioavailability (F) quantifies the proportion of an administered drug that reaches the systemic circulation, reflecting absorption and first-pass metabolism effects.

Question 2

What is the primary site of drug metabolism in the body?

Accepted Answer

Liver

Answer

The liver is the primary organ for drug metabolism, containing abundant cytochrome P450 enzymes that transform drugs into more water-soluble metabolites for excretion.

Question 3

Which drug formulation property determines whether a tablet should NOT be crushed?

Accepted Answer

Extended-release (ER/XR) coating or enteric coating

Answer

Extended-release and enteric-coated tablets have specialised coatings that control drug release rate or protect the stomach; crushing destroys this mechanism and can cause toxicity or reduced efficacy.

Question 4

What is the Henderson-Hasselbalch equation used for in pharmacy?

Accepted Answer

Calculating the degree of ionisation of a drug at a given pH

Answer

The Henderson-Hasselbalch equation relates pH, pKa, and the ratio of ionised to un-ionised drug, predicting drug absorption and distribution across biological membranes.

Question 5

Which process describes the elimination of a drug from the body at a constant fraction per unit time, regardless of plasma concentration?

Accepted Answer

First-order elimination kinetics

Answer

First-order kinetics means a constant percentage of the drug is eliminated per unit time, so the rate of elimination is proportional to the plasma concentration.

DHA Pharmacist Practice Test

DHA Pharmacist Practice Test

DHA Pharmacist Pharmaceutical Sciences