B.Pharm. Bachelor of Pharmacy Bachelor of Pharmacy (B.Pharm.) Pharmaceutics 2 — Questions and Answers
Question 1: Which rheological property describes a fluid whose viscosity decreases under shear stress but recovers when stress is removed?
- Thixotropy (Correct answer)
- Dilatancy
- Plasticity
- Newtonian flow
Correct answer: Thixotropy
Thixotropy refers to a reversible, time-dependent decrease in viscosity upon application of shear stress.
Question 2: The Henderson-Hasselbalch equation is primarily used in pharmacy to calculate:
- Osmolarity of IV solutions
- pH of buffer systems (Correct answer)
- Partition coefficient of drugs
- Rate of drug degradation
Correct answer: pH of buffer systems
The Henderson-Hasselbalch equation relates pH, pKa, and the ratio of conjugate base to acid in a buffer.
Question 3: Which type of emulsion is preferred for intravenous administration of lipophilic drugs?
- Water-in-oil (W/O)
- Oil-in-water (O/W) (Correct answer)
- Multiple W/O/W
- Microemulsion with surfactant above CMC
Correct answer: Oil-in-water (O/W)
O/W emulsions place oil droplets in a continuous aqueous phase, making them compatible with blood for IV use.
Question 4: Fick's first law of diffusion states that the rate of drug permeation is directly proportional to:
- Square root of time
- Concentration gradient (Correct answer)
- Particle size squared
- Viscosity of the medium
Correct answer: Concentration gradient
Fick's first law: flux = -D × (dC/dx), showing flux is proportional to the concentration gradient.
Question 5: Supercritical fluid technology using CO₂ is most commonly applied in pharmaceutical manufacturing to:
- Sterilize heat-labile biologics
- Micronize drug particles (Correct answer)
- Coat enteric tablets
- Prepare liposomes
Correct answer: Micronize drug particles
Supercritical CO₂ is used in particle engineering (RESS, SAS processes) to produce fine, uniform drug particles.
Question 6: The term 'apparent volume of distribution' (Vd) exceeding total body water (~42 L in a 70 kg adult) indicates that the drug:
- Is confined to the plasma compartment
- Is extensively bound to plasma proteins
- Partitions significantly into tissues (Correct answer)
- Has poor oral bioavailability
Correct answer: Partitions significantly into tissues
A large Vd indicates extensive tissue distribution and sequestration outside the vascular compartment.
Question 7: Which preservative system is most commonly used in ophthalmic preparations to prevent microbial contamination?
- Benzalkonium chloride (Correct answer)
- Sodium benzoate
- Methylparaben
- Thimerosal at 0.1%
Correct answer: Benzalkonium chloride
Benzalkonium chloride (BAK) is the most widely used preservative in ophthalmic drops due to its broad-spectrum activity.
