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.
- A biphasic liquid dosage form consists of:
- One homogenous phase
- Two distinct phases
- Only solid ingredients
- Only gaseous ingredients
- Which of the following is an example of a suspension?
- Calamine Lotion
- Simple Syrup
- Peppermint Spirit
- Camphor Water
- An emulsion is a system containing two:
- Miscible liquids
- Immiscible liquids
- Soluble solids
- Gases
- In a suspension, the formation of a hard, non-resuspendable sediment is known as:
- Flocculation
- Creaming
- Caking
- Coalescence
- The HLB (Hydrophile-Lipophile Balance) system is used to select:
- Suspending agents
- Emulsifying agents
- Sweeteners
- Preservatives
- A suspension where particles settle slowly to form a dense cake is a(n):
- Flocculated suspension
- Deflocculated suspension
- o/w emulsion
- w/o emulsion
- 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
- The upward movement of dispersed globules in an emulsion is called:
- Sedimentation
- Creaming
- Breaking
- Phase inversion
- Which law describes the rate of sedimentation of particles in a suspension?
- Fick’s Law
- Noyes-Whitney Law
- Stoke’s Law
- Ohm’s Law
- A mandatory auxiliary label for all suspensions is:
- For External Use Only
- Shake Well Before Use
- Store in a Cool Place
- Do Not Freeze
- An o/w emulsion can be diluted with:
- Oil
- Water
- Alcohol
- Hexane
- In a flocculated suspension, the particles exist as:
- Separate individual entities
- Loosely bound aggregates or flocs
- Dissolved molecules
- Liquid droplets
- The irreversible breakdown of an emulsion where the dispersed phase separates is called:
- Creaming
- Coalescence
- Cracking or Breaking
- Flocculation
- Substances that increase the viscosity of the dispersion medium are known as:
- Wetting agents
- Emulsifying agents
- Suspending agents
- Flocculating agents
- In a w/o emulsion, the continuous or external phase is:
- Water
- Oil
- A solid
- A gas
- The merging of small dispersed droplets to form larger droplets in an emulsion is known as:
- Creaming
- Coalescence
- Phase inversion
- Breaking
- 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.
- An emulsifying agent with a high HLB value (8-18) is suitable for making a(n):
- w/o emulsion
- o/w emulsion
- suspension
- ointment
- 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
- A change from an o/w to a w/o emulsion, or vice versa, is called:
- Breaking
- Creaming
- Phase inversion
- Coalescence
- 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
- The dry gum method and the wet gum method are used for the preparation of:
- Suspensions
- Elixirs
- Emulsions
- Syrups
- 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.
- Which stability problem is reversible in an emulsion?
- Breaking
- Coalescence
- Creaming
- Phase inversion
- An example of a natural emulsifying agent is:
- Sodium lauryl sulphate
- Acacia
- Polysorbate 80 (Tween 80)
- Sorbitan monooleate (Span 80)
- 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
- 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
- The most significant disadvantage of a suspension is its:
- Unpleasant taste
- Inherent physical instability
- Slow onset of action
- High cost
- 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
- Which of the following is NOT a biphasic liquid?
- Suspension
- Emulsion
- Magma
- Elixir
- 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
- 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
- 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.
- Which test involves measuring the electrical current flow through an emulsion?
- Dilution test
- Dye test
- Conductivity test
- Viscosity test
- The dispersed phase in a suspension is the:
- Insoluble solid particle
- Liquid medium
- Emulsifying agent
- Soluble drug
- The continuous phase of an emulsion is also known as the:
- Internal phase
- Dispersed phase
- External phase
- Immiscible phase
- 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.
- A low HLB value (3-6) for an emulsifier indicates it is suitable for:
- o/w emulsions
- w/o emulsions
- Solubilizing agents
- Detergents
- 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
- Milk is a natural example of a(n):
- Suspension
- Solution
- Elixir
- Emulsion
- 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
- 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
- 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
- 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
- Which of the following represents a stability problem in a suspension?
- Caking
- Creaming
- Coalescence
- Breaking
- Which of the following represents a stability problem in an emulsion?
- Caking
- Sedimentation
- Breaking
- Flocculation of solid particles
- To formulate a suspension, a drug must be ______ in the vehicle.
- Soluble
- Practically insoluble
- Volatile
- Miscible
- 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
- 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
- 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
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
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