Pharm.D. Doctor of Pharmacy Pharmaceutical Chemistry and Drug Design 1 — Questions and Answers
Question 1: Which functional group is primarily responsible for the acidic properties of aspirin?
- Ester group
- Carboxylic acid group (Correct answer)
- Hydroxyl group
- Ketone group
Correct answer: Carboxylic acid group
The carboxylic acid (–COOH) group in aspirin (acetylsalicylic acid) is responsible for its acidic properties and contributes to gastric irritation.
Question 2: In prodrug design, the active drug is released after:
- Binding to its receptor target
- Metabolic or chemical conversion in the body (Correct answer)
- Renal filtration
- Passive diffusion across the blood-brain barrier
Correct answer: Metabolic or chemical conversion in the body
Prodrugs are pharmacologically inactive compounds that undergo metabolic or chemical biotransformation to release the active drug in the body.
Question 3: Which stereochemical concept explains why (R)- and (S)-ibuprofen differ in pharmacological activity?
- Constitutional isomerism
- Geometric isomerism
- Chirality and enantioselectivity (Correct answer)
- Conformational isomerism
Correct answer: Chirality and enantioselectivity
Chirality results in enantiomers that interact differently with stereospecific biological targets; S-ibuprofen is the active form that inhibits COX enzymes.
Question 4: What does structure-activity relationship (SAR) studies primarily determine?
- How quickly a drug is absorbed
- How chemical structure modifications affect pharmacological activity (Correct answer)
- The molecular weight of candidate drugs
- The route of administration for new drugs
Correct answer: How chemical structure modifications affect pharmacological activity
SAR studies examine how changes in a molecule's chemical structure affect its biological activity, guiding medicinal chemists in optimizing drug candidates.
Question 5: Which principle in drug design states that increasing lipophilicity generally improves CNS penetration?
- Henderson-Hasselbalch principle
- Lipinski's Rule of Five (Correct answer)
- Biopharmaceutics Classification System
- Lock-and-key model
Correct answer: Lipinski's Rule of Five
Lipinski's Rule of Five guides oral drug design by defining physicochemical properties for good bioavailability, and lipophilicity (logP) is a key factor in CNS penetration.
Question 6: Beta-lactam antibiotics exert their antibacterial effect by:
- Inhibiting DNA gyrase
- Irreversibly binding to penicillin-binding proteins (PBPs) and inhibiting cell wall synthesis (Correct answer)
- Disrupting the bacterial cell membrane
- Inhibiting the 30S ribosomal subunit
Correct answer: Irreversibly binding to penicillin-binding proteins (PBPs) and inhibiting cell wall synthesis
Beta-lactam antibiotics covalently and irreversibly bind to penicillin-binding proteins (transpeptidases), inhibiting bacterial cell wall (peptidoglycan) cross-linking.
