Pharmacy Pharmaceutical Chemistry 4

Question 1

Which metabolic pathway is responsible for the conversion of codeine to morphine in the body?

Accepted Answer

O-demethylation by CYP2D6

Answer

CYP2D6 catalyzes O-demethylation of codeine at the 3-methoxy position, converting it to the more pharmacologically active morphine.

Question 2

The Maillard reaction in pharmaceutical formulations refers to:

Accepted Answer

Non-enzymatic browning reaction between reducing sugars and amines

Answer

The Maillard reaction is a non-enzymatic condensation between reducing sugars (excipients like lactose) and primary amines in drug molecules, causing discoloration and potency loss.

Question 3

Which property of a drug is described by its logP value?

Accepted Answer

Lipophilicity (partition between octanol and water)

Answer

LogP (octanol-water partition coefficient) quantifies lipophilicity; a higher logP indicates greater lipid solubility and typically better membrane permeability.

Question 4

Sulfonamide antibiotics act by competitively inhibiting the bacterial enzyme that uses which substrate?

Accepted Answer

Para-aminobenzoic acid (PABA)

Answer

Sulfonamides structurally mimic PABA and competitively inhibit dihydropteroate synthase, blocking bacterial folate synthesis.

Question 5

In NMR spectroscopy, the chemical shift (δ) of a proton is primarily influenced by:

Accepted Answer

The electron density around the proton (shielding/deshielding)

Answer

Electron-withdrawing groups deshield nearby protons (downfield shift, higher δ) while electron-donating groups increase shielding (upfield shift, lower δ).

Pharmacy Practice Test

Pharmacy Practice Test

Pharmacy Pharmaceutical Chemistry 4