MCQ Quiz: Biphasic Liquid

Biphasic liquids, comprising suspensions and emulsions, are indispensable dosage forms for administering water-insoluble drugs. For B.Pharm students, understanding these two-phase systems is crucial for formulation and development. This quiz covers the fundamental principles, stability challenges, and evaluation methods for suspensions (solid-in-liquid) and emulsions (liquid-in-liquid), providing a comprehensive test of your knowledge on this core pharmaceutical topic.

1. A biphasic liquid dosage form consists of:
   • One homogenous phase
   • Two distinct phases
   • Only solid ingredients
   • Only gaseous ingredients
   Answer: Two distinct phases
2. Which of the following is an example of a suspension?
   • Calamine Lotion
   • Simple Syrup
   • Peppermint Spirit
   • Camphor Water
   Answer: Calamine Lotion
3. An emulsion is a system containing two:
   • Miscible liquids
   • Immiscible liquids
   • Soluble solids
   • Gases
   Answer: Immiscible liquids
4. In a suspension, the formation of a hard, non-resuspendable sediment is known as:
   • Flocculation
   • Creaming
   • Caking
   • Coalescence
   Answer: Caking
5. The HLB (Hydrophile-Lipophile Balance) system is used to select:
   • Suspending agents
   • Emulsifying agents
   • Sweeteners
   • Preservatives
   Answer: Emulsifying agents
6. A suspension where particles settle slowly to form a dense cake is a(n):
   • Flocculated suspension
   • Deflocculated suspension
   • o/w emulsion
   • w/o emulsion
   Answer: Deflocculated suspension
7. The dilution test is used to determine:
   • The stability of a suspension
   • The particle size of a solid
   • The type of emulsion (o/w or w/o)
   • The viscosity of a liquid
   Answer: The type of emulsion (o/w or w/o)
8. The upward movement of dispersed globules in an emulsion is called:
   • Sedimentation
   • Creaming
   • Breaking
   • Phase inversion
   Answer: Creaming
9. Which law describes the rate of sedimentation of particles in a suspension?
   • Fick’s Law
   • Noyes-Whitney Law
   • Stoke’s Law
   • Ohm’s Law
   Answer: Stoke’s Law
10. A mandatory auxiliary label for all suspensions is:
    • For External Use Only
    • Shake Well Before Use
    • Store in a Cool Place
    • Do Not Freeze
    Answer: Shake Well Before Use
11. An o/w emulsion can be diluted with:
    • Oil
    • Water
    • Alcohol
    • Hexane
    Answer: Water
12. In a flocculated suspension, the particles exist as:
    • Separate individual entities
    • Loosely bound aggregates or flocs
    • Dissolved molecules
    • Liquid droplets
    Answer: Loosely bound aggregates or flocs
13. The irreversible breakdown of an emulsion where the dispersed phase separates is called:
    • Creaming
    • Coalescence
    • Cracking or Breaking
    • Flocculation
    Answer: Cracking or Breaking
14. Substances that increase the viscosity of the dispersion medium are known as:
    • Wetting agents
    • Emulsifying agents
    • Suspending agents
    • Flocculating agents
    Answer: Suspending agents
15. In a w/o emulsion, the continuous or external phase is:
    • Water
    • Oil
    • A solid
    • A gas
    Answer: Oil
16. The merging of small dispersed droplets to form larger droplets in an emulsion is known as:
    • Creaming
    • Coalescence
    • Phase inversion
    • Breaking
    Answer: Coalescence
17. Which is a key advantage of suspensions as a dosage form?
    • They are physically stable.
    • They can improve the stability of drugs unstable in solution.
    • They provide accurate dosing.
    • They are clear and elegant.
    Answer: They can improve the stability of drugs unstable in solution.
18. An emulsifying agent with a high HLB value (8-18) is suitable for making a(n):
    • w/o emulsion
    • o/w emulsion
    • suspension
    • ointment
    Answer: o/w emulsion
19. The sedimentation volume of a suspension is the ratio of the:
    • Initial volume of suspension to the final volume of sediment
    • Final volume of sediment to the initial volume of suspension
    • Initial particle size to the final particle size
    • Viscosity of the medium to the density of the particles
    Answer: Final volume of sediment to the initial volume of suspension
20. A change from an o/w to a w/o emulsion, or vice versa, is called:
    • Breaking
    • Creaming
    • Phase inversion
    • Coalescence
    Answer: Phase inversion
21. A wetting agent is used in suspensions to:
    • Increase viscosity
    • Decrease the interfacial tension between solid particles and the liquid medium
    • Sweeten the formulation
    • Act as a preservative
    Answer: Decrease the interfacial tension between solid particles and the liquid medium
22. The dry gum method and the wet gum method are used for the preparation of:
    • Suspensions
    • Elixirs
    • Emulsions
    • Syrups
    Answer: Emulsions
23. Which statement is true for a deflocculated suspension?
    • The sediment is easy to redisperse.
    • The rate of sedimentation is high.
    • The supernatant is cloudy.
    • The particles exist as separate entities.
    Answer: The particles exist as separate entities.
24. Which stability problem is reversible in an emulsion?
    • Breaking
    • Coalescence
    • Creaming
    • Phase inversion
    Answer: Creaming
25. An example of a natural emulsifying agent is:
    • Sodium lauryl sulphate
    • Acacia
    • Polysorbate 80 (Tween 80)
    • Sorbitan monooleate (Span 80)
    Answer: Acacia
26. According to Stoke’s Law, the sedimentation rate decreases if the:
    • Particle size increases
    • Viscosity of the medium decreases
    • Viscosity of the medium increases
    • Density difference increases
    Answer: Viscosity of the medium increases
27. A w/o emulsion generally feels:
    • Non-greasy and is easily washed off
    • Greasy and is not easily washed off
    • Like a powder
    • Like a clear solution
    Answer: Greasy and is not easily washed off
28. The most significant disadvantage of a suspension is its:
    • Unpleasant taste
    • Inherent physical instability
    • Slow onset of action
    • High cost
    Answer: Inherent physical instability
29. In the dye solubility test, if an oil-soluble dye colors the continuous phase, the emulsion is:
    • o/w type
    • w/o type
    • Broken
    • A suspension
    Answer: w/o type
30. Which of the following is NOT a biphasic liquid?
    • Suspension
    • Emulsion
    • Magma
    • Elixir
    Answer: Elixir
31. Flocculating agents are added to a suspension to:
    • Prevent particle aggregation
    • Form loose, easily re-dispersible aggregates
    • Increase the density of the particles
    • Dissolve the solid particles
    Answer: Form loose, easily re-dispersible aggregates
32. An emulsifying agent works by:
    • Increasing the interfacial tension between two immiscible liquids
    • Decreasing the interfacial tension and forming a film around dispersed droplets
    • Dissolving one liquid in the other
    • Precipitating the dispersed phase
    Answer: Decreasing the interfacial tension and forming a film around dispersed droplets
33. A “caked” suspension is undesirable because:
    • It looks unpleasant.
    • The sediment cannot be uniformly redispersed.
    • It has a bad taste.
    • It is too viscous to pour.
    Answer: The sediment cannot be uniformly redispersed.
34. Which test involves measuring the electrical current flow through an emulsion?
    • Dilution test
    • Dye test
    • Conductivity test
    • Viscosity test
    Answer: Conductivity test
35. The dispersed phase in a suspension is the:
    • Insoluble solid particle
    • Liquid medium
    • Emulsifying agent
    • Soluble drug
    Answer: Insoluble solid particle
36. The continuous phase of an emulsion is also known as the:
    • Internal phase
    • Dispersed phase
    • External phase
    • Immiscible phase
    Answer: External phase
37. Which is a desirable feature of a flocculated suspension?
    • The sediment is difficult to redisperse.
    • The particles settle rapidly.
    • The supernatant is clear.
    • The particles are small and uniform.
    Answer: The particles settle rapidly.
38. A low HLB value (3-6) for an emulsifier indicates it is suitable for:
    • o/w emulsions
    • w/o emulsions
    • Solubilizing agents
    • Detergents
    Answer: w/o emulsions
39. The primary purpose of preparing a pharmaceutical suspension is to:
    • Administer a drug that is insoluble in a desired vehicle
    • Ensure rapid absorption
    • Provide a clear liquid
    • Avoid first-pass metabolism
    Answer: Administer a drug that is insoluble in a desired vehicle
40. Milk is a natural example of a(n):
    • Suspension
    • Solution
    • Elixir
    • Emulsion
    Answer: Emulsion
41. In a suspension, Ostwald ripening refers to:
    • The growth of larger crystals at the expense of smaller ones
    • The formation of flocs
    • The settling of particles
    • The formation of a hard cake
    Answer: The growth of larger crystals at the expense of smaller ones
42. A conductivity test would show high conductivity for which type of emulsion?
    • w/o
    • o/w
    • Both would have high conductivity
    • Neither would conduct electricity
    Answer: o/w
43. Which factor is NOT part of the Stoke’s equation for sedimentation velocity?
    • Particle diameter
    • Density of the particle and medium
    • Viscosity of the medium
    • Surface tension of the medium
    Answer: Surface tension of the medium
44. The ratio of oil to water to gum in the primary emulsion of the dry gum method is typically:
    • 1:2:4
    • 4:2:1
    • 2:4:1
    • 1:4:2
    Answer: 4:2:1
45. Which of the following represents a stability problem in a suspension?
    • Caking
    • Creaming
    • Coalescence
    • Breaking
    Answer: Caking
46. Which of the following represents a stability problem in an emulsion?
    • Caking
    • Sedimentation
    • Breaking
    • Flocculation of solid particles
    Answer: Breaking
47. To formulate a suspension, a drug must be ______ in the vehicle.
    • Soluble
    • Practically insoluble
    • Volatile
    • Miscible
    Answer: Practically insoluble
48. An emulsifier stabilizes an emulsion by:
    • Increasing the density of the internal phase
    • Forming a protective barrier around the droplets of the dispersed phase
    • Increasing the particle size of the dispersed phase
    • Removing the charge from the droplets
    Answer: Forming a protective barrier around the droplets of the dispersed phase
49. A high sedimentation volume (close to 1) indicates that the suspension is:
    • Caked
    • Deflocculated
    • Aesthetically pleasing but potentially unstable
    • Likely to be a stable, flocculated system
    Answer: Likely to be a stable, flocculated system
50. The main difference between a suspension and an emulsion is the:
    • Number of phases
    • Nature of the dispersed phase (solid vs. liquid)
    • Route of administration
    • Presence of a preservative
    Answer: Nature of the dispersed phase (solid vs. liquid)

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