MCQ Quiz- Suspensions

MCQ Quiz: Suspensions

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Suspensions are a vital biphasic dosage form, essential for delivering insoluble drug particles in a liquid vehicle. For B.Pharm students, mastering the formulation and stabilization of these systems is a core pharmaceutical skill. This quiz focuses on the key concepts of suspension technology, including the critical differences between flocculated and deflocculated systems, major stability challenges like caking, and the role of various formulation excipients.

  1. A pharmaceutical suspension is a biphasic dosage form consisting of:
    • Two immiscible liquids
    • A gas dispersed in a liquid
    • Finely divided solid particles dispersed in a liquid medium
    • A liquid dispersed in a solid
    Answer: Finely divided solid particles dispersed in a liquid medium
  2. The most critical and irreversible stability problem in suspensions is:
    • Creaming
    • Flocculation
    • Caking
    • Sedimentation
    Answer: Caking
  3. In which type of suspension do the particles exist as separate, fine entities?
    • Flocculated
    • Deflocculated
    • Emulsified
    • Saturated
    Answer: Deflocculated
  4. The formation of loose, lightweight aggregates of particles in a suspension is known as:
    • Caking
    • Flocculation
    • Coalescence
    • Creaming
    Answer: Flocculation
  5. Which law describes the rate of settling of particles in a suspension?
    • Fick’s Law
    • Stoke’s Law
    • Noyes-Whitney Law
    • Henderson-Hasselbalch Law
    Answer: Stoke’s Law
  6. A suspending agent is added to a suspension to:
    • Increase the viscosity of the vehicle
    • Dissolve the solid particles
    • Make the particles flocculate
    • Wet the solid particles
    Answer: Increase the viscosity of the vehicle
  7. Which statement is true for a deflocculated suspension?
    • The particles settle rapidly.
    • The sediment is loosely packed and easy to redisperse.
    • The particles settle slowly and can form a hard cake.
    • The supernatant is clear.
    Answer: The particles settle slowly and can form a hard cake.
  8. A “Shake Well Before Use” label is required for which dosage form?
    • Solution
    • Elixir
    • Syrup
    • Suspension
    Answer: Suspension
  9. The ratio of the final volume of the sediment (Vu) to the original volume of the suspension (Vo) is the:
    • Degree of flocculation
    • Sedimentation volume
    • Angle of repose
    • HLB value
    Answer: Sedimentation volume
  10. Wetting agents are used in suspensions to:
    • Increase the density of the particles.
    • Decrease the interfacial tension between the solid particles and the liquid vehicle.
    • Make the suspension taste better.
    • Act as a preservative.
    Answer: Decrease the interfacial tension between the solid particles and the liquid vehicle.
  11. Which of the following is an advantage of a flocculated suspension?
    • The sediment is difficult to redisperse.
    • The suspension appears elegant and uniform.
    • The sediment does not form a hard cake.
    • The particles settle very slowly.
    Answer: The sediment does not form a hard cake.
  12. According to Stoke’s Law, the rate of sedimentation will decrease if the:
    • Particle size is increased.
    • Viscosity of the medium is increased.
    • Density of the particle is increased.
    • Density of the medium is decreased.
    Answer: Viscosity of the medium is increased.
  13. Which of the following can act as a flocculating agent?
    • Electrolytes
    • Surfactants
    • Polymers
    • All of the above
    Answer: All of the above
  14. The growth of large particles at the expense of smaller ones in a suspension is known as:
    • Caking
    • Ostwald Ripening
    • Flocculation
    • Phase inversion
    Answer: Ostwald Ripening
  15. For an ideal suspension, the sedimentation volume should be:
    • Equal to zero
    • As low as possible
    • Equal to or close to 1
    • Greater than 1
    Answer: Equal to or close to 1
  16. A major advantage of suspensions is the ability to:
    • Administer drugs that are insoluble in common vehicles.
    • Ensure dose-to-dose uniformity without shaking.
    • Provide a clear, transparent product.
    • Avoid first-pass metabolism.
    Answer: Administer drugs that are insoluble in common vehicles.
  17. Which of the following is NOT a desired property of a pharmaceutical suspension?
    • Particles should settle slowly.
    • The formulation should be physically and chemically stable.
    • The sediment should form a hard cake.
    • It should be easy to pour and administer.
    Answer: The sediment should form a hard cake.
  18. The supernatant of a flocculated suspension is typically:
    • Cloudy
    • Clear
    • Viscous
    • Colored
    Answer: Clear
  19. An excipient like methylcellulose or tragacanth is added to a suspension as a(n):
    • Wetting agent
    • Flocculating agent
    • Suspending agent
    • Emulsifying agent
    Answer: Suspending agent
  20. The dispersed phase in a suspension is the:
    • Liquid vehicle
    • Insoluble solid particle
    • Emulsifier
    • Soluble drug
    Answer: Insoluble solid particle
  21. To prevent caking in a suspension, it is often desirable to formulate it as a(n):
    • Deflocculated system
    • Flocculated system
    • Solution
    • Emulsion
    Answer: Flocculated system
  22. The rate of sedimentation is directly proportional to the:
    • Viscosity of the medium
    • Square of the particle’s diameter
    • Density of the medium
    • Length of the container
    Answer: Square of the particle’s diameter
  23. Which of the following is a disadvantage of suspensions?
    • Difficulty in maintaining dose uniformity.
    • Physical instability (sedimentation and caking).
    • Bulky and difficult to transport.
    • All of the above.
    Answer: All of the above.
  24. The first step in preparing a suspension of a hydrophobic drug is to:
    • Add the suspending agent.
    • Add a wetting agent.
    • Heat the vehicle.
    • Add a preservative.
    Answer: Add a wetting agent.
  25. The external phase or continuous phase in a suspension is the:
    • Solid particle
    • Liquid vehicle
    • Dissolved drug
    • Flocculating agent
    Answer: Liquid vehicle
  26. In a deflocculated suspension, the interparticle forces are primarily:
    • Attractive
    • Repulsive
    • Neutral
    • Both attractive and repulsive
    Answer: Repulsive
  27. A structured vehicle in a suspension is one that has:
    • High viscosity at rest and low viscosity when shaken.
    • Low viscosity at all times.
    • High viscosity at all times.
    • A two-phase system.
    Answer: High viscosity at rest and low viscosity when shaken.
  28. The appearance of a deflocculated suspension is generally considered:
    • Aesthetically pleasing and uniform
    • Unpleasant due to rapid settling
    • Clear
    • Hazy
    Answer: Aesthetically pleasing and uniform
  29. Which of the following is a synthetic suspending agent?
    • Acacia
    • Tragacanth
    • Carbomer (Carbopol)
    • Bentonite
    Answer: Carbomer (Carbopol)
  30. The degree of flocculation (β) is the ratio of:
    • Sedimentation volume of flocculated suspension to deflocculated suspension.
    • Sedimentation volume of deflocculated suspension to flocculated suspension.
    • Initial volume to final volume.
    • Final volume to initial volume.
    Answer: Sedimentation volume of flocculated suspension to deflocculated suspension.
  31. Why must suspensions be protected from freezing and thawing cycles?
    • It can cause irreversible crystal growth and aggregation.
    • It can cause the vehicle to evaporate.
    • It can cause the drug to dissolve.
    • It can inactivate the preservative.
    Answer: It can cause irreversible crystal growth and aggregation.
  32. The “caking diagram” plots sedimentation volume against:
    • Time
    • Temperature
    • Concentration of flocculating agent
    • Particle size
    Answer: Concentration of flocculating agent
  33. A substance that exhibits shear-thinning (thixotropic) properties is ideal as a:
    • Wetting agent
    • Flocculating agent
    • Suspending agent
    • Preservative
    Answer: Suspending agent
  34. The term “dispersed system” can be used to describe:
    • Only solutions
    • Only suspensions
    • Only emulsions
    • Both suspensions and emulsions
    Answer: Both suspensions and emulsions
  35. Which of the following is an example of a wetting agent?
    • Methylcellulose
    • Bentonite
    • Polysorbate 80 (Tween 80)
    • Sodium chloride
    Answer: Polysorbate 80 (Tween 80)
  36. The Zeta potential is a measure of the:
    • Particle size in a suspension
    • Magnitude of the repulsive forces between adjacent particles
    • Viscosity of the suspension
    • Rate of sedimentation
    Answer: Magnitude of the repulsive forces between adjacent particles
  37. A controlled flocculation is the desired state for a stable suspension because it:
    • Prevents sedimentation completely.
    • Prevents the formation of a hard cake.
    • Makes the suspension look clear.
    • Dissolves the drug particles.
    Answer: Prevents the formation of a hard cake.
  38. Which of the following is an advantage of a deflocculated suspension?
    • It is physically stable.
    • The particles settle slowly.
    • It is easy to redisperse.
    • It does not form a cake.
    Answer: The particles settle slowly.
  39. The size of the particles in a pharmaceutical suspension is typically in the range of:
    • < 1 nanometer
    • 1-50 micrometers
    • 1 millimeter
    • 1-50 nanometers
    Answer: 1-50 micrometers
  40. The addition of an electrolyte can cause flocculation by:
    • Increasing the viscosity
    • Reducing the zeta potential of the particles
    • Coating the particles
    • Increasing the density of the vehicle
    Answer: Reducing the zeta potential of the particles
  41. A primary purpose for formulating drugs as a suspension is to:
    • Improve the taste of a bitter drug.
    • Increase the solubility of a drug.
    • Avoid first-pass metabolism.
    • Provide a sterile preparation.
    Answer: Improve the taste of a bitter drug.
  42. If the sedimentation volume (F) is 0.5, it means that:
    • The sediment occupies 50% of the total volume of the suspension.
    • The suspension is 50% flocculated.
    • The particles are 50% dissolved.
    • The suspension is 50% stable.
    Answer: The sediment occupies 50% of the total volume of the suspension.
  43. A substance that reduces the contact angle between a solid and a liquid is a:
    • Suspending agent
    • Wetting agent
    • Thickening agent
    • Buffer
    Answer: Wetting agent
  44. Which of the following is NOT a method to prepare a suspension?
    • Precipitation method
    • Dispersion method
    • Dry gum method
    • Use of controlled flocculation
    Answer: Dry gum method
  45. The opposite of caking is:
    • Easy redispersion
    • Sedimentation
    • Flocculation
    • Creaming
    Answer: Easy redispersion
  46. In a well-formulated suspension, the rheological property desired is:
    • Newtonian flow
    • Dilatant flow
    • Thixotropy (shear-thinning)
    • High viscosity at all times
    Answer: Thixotropy (shear-thinning)
  47. To make a suspension, the drug particles must be ______ in the vehicle.
    • Completely soluble
    • Sparingly soluble
    • Practically insoluble
    • Volatile
    Answer: Practically insoluble
  48. The supernatant of a deflocculated suspension remains cloudy for a longer period because:
    • The particles are large and settle quickly.
    • Even the smallest particles settle very slowly.
    • The vehicle is very viscous.
    • The particles are aggregated.
    Answer: Even the smallest particles settle very slowly.
  49. Which is a natural polysaccharide used as a suspending agent?
    • Carbopol
    • Acacia
    • HPMC
    • PVP
    Answer: Acacia
  50. The fundamental difference between a suspension and a solution is the:
    • Number of phases
    • Color
    • Route of administration
    • Type of preservative used
    Answer: Number of phases

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