MChem Master of Chemistry Master of Chemistry: Pharmaceutical Chemistry 3

Question 1

Which mechanism underlies the anticoagulant action of warfarin at the molecular level?

Accepted Answer

Inhibition of vitamin K epoxide reductase

Answer

Warfarin inhibits vitamin K epoxide reductase, preventing regeneration of reduced vitamin K required for γ-carboxylation of clotting factors II, VII, IX, and X.

Question 2

In QSAR studies, the Hammett sigma constant (σ) characterizes which molecular property of substituents?

Accepted Answer

Electronic effects on aromatic systems

Answer

The Hammett σ constant quantifies the electron-donating or electron-withdrawing electronic effect of substituents on aromatic ring systems.

Question 3

Which salt form strategy is most effective for improving the dissolution rate of a BCS Class II drug?

Accepted Answer

Conversion to a hydrochloride or sodium salt

Answer

Forming ionizable salts (e.g., HCl or Na salts) dramatically increases the dissolution rate of poorly soluble BCS Class II drugs by improving wettability and solubility.

Question 4

The Hansch analysis in medicinal chemistry uses the partition coefficient (π) to quantify which parameter?

Accepted Answer

Substituent lipophilicity

Answer

The Hansch π parameter measures the relative lipophilicity contribution of a substituent compared to hydrogen (π = logP_substituted − logP_unsubstituted).

Question 5

Which crystal form consideration is critical during pharmaceutical development due to its impact on bioavailability?

Accepted Answer

Polymorphism

Answer

Polymorphism (existence of multiple crystal forms of the same molecule) critically affects solubility, dissolution rate, and consequently oral bioavailability.

MChem Master of Chemistry Practice Test

MChem Master of Chemistry Practice Test

MChem Master of Chemistry Master of Chemistry: Pharmaceutical Chemistry 3