B.Pharm. Bachelor of Pharmacy Bachelor of Pharmacy (B.Pharm.) Pharmaceutical Chemistry 3

Question 1

Which physicochemical property is described by Lipinski's Rule of Five for oral drug-likeness?

Accepted Answer

Molecular weight ≤500 Da, logP ≤5, H-bond donors ≤5, H-bond acceptors ≤10

Answer

Lipinski's Rule of Five states orally bioavailable drugs typically have MW ≤500, logP ≤5, H-bond donors ≤5, and H-bond acceptors ≤10.

Question 2

What is the principal difference between a racemate and a meso compound?

Accepted Answer

A meso compound is optically inactive due to internal symmetry; a racemate is a 50:50 mixture of enantiomers

Answer

A meso compound is achiral due to an internal plane of symmetry, while a racemate is an equimolar mixture of two enantiomers.

Question 3

Which spectroscopic technique is MOST useful for determining the three-dimensional structure of a drug molecule in solution?

Accepted Answer

Nuclear Magnetic Resonance (NMR) spectroscopy

Answer

NMR spectroscopy provides detailed information about connectivity, stereochemistry, and three-dimensional conformation of molecules in solution.

Question 4

What is the purpose of a buffer system in a pharmaceutical formulation?

Accepted Answer

To maintain a constant pH and ensure drug stability and efficacy

Answer

Buffers resist changes in pH, protecting drug stability, preventing degradation, and ensuring consistent therapeutic effect.

Question 5

In phase I metabolic reactions, which enzyme superfamily is primarily responsible for oxidative drug biotransformation?

Accepted Answer

Cytochrome P450 (CYP) enzymes

Answer

Cytochrome P450 enzymes, predominantly in the liver, catalyze oxidative reactions such as hydroxylation and epoxidation in phase I drug metabolism.

B.Pharm. Bachelor of Pharmacy Practice Test