PSI Pharmaceutical Sciences 2

Question 1

Which parameter best describes the rate of drug elimination from the body?

Accepted Answer

Half-life (t½)

Answer

Half-life is the time taken for plasma drug concentration to fall by 50%. It directly reflects the rate of elimination and determines dosing intervals.

Question 2

Michaelis-Menten kinetics apply when enzyme-mediated metabolism is:

Accepted Answer

Saturated at high drug concentrations

Answer

At high concentrations, metabolic enzymes become saturated and elimination shifts from first-order to zero-order kinetics — described by Michaelis-Menten equations.

Question 3

Which solid dosage form release mechanism uses an osmotic pump?

Accepted Answer

OROS (Osmotic Release Oral System)

Answer

OROS uses osmotic pressure to drive water into a core compartment, pushing drug through a laser-drilled orifice at a controlled, constant rate.

Question 4

Which property does the partition coefficient (log P) measure?

Accepted Answer

Lipophilicity of a drug

Answer

Log P is the ratio of drug concentration in octanol vs water, indicating how lipophilic a molecule is. High log P means good membrane permeability but poor aqueous solubility.

Question 5

Hygroscopic drug substances require which type of packaging?

Accepted Answer

Moisture-barrier packaging

Answer

Hygroscopic substances absorb moisture from the environment, leading to degradation. Moisture-barrier packaging (e.g., blister with aluminium foil) protects product stability.

PSI Pharmacy Practice Test

PSI Pharmacy Practice Test

PSI Pharmaceutical Sciences 2