Advantages and disadvantages of suspensions MCQs With Answer

Introduction: Understanding the advantages and disadvantages of suspensions is essential for B. Pharm students preparing for formulation and quality-control roles. Pharmaceutical suspensions offer benefits like improved bioavailability of poorly soluble drugs, dose flexibility, and taste masking, while posing challenges such as sedimentation, caking, dosing inaccuracy, microbial contamination, and complex rheology. Key formulation factors include particle size, zeta potential, wetting agents, suspending agents, preservatives, and pH control. Evaluation employs sedimentation volume, redispersibility, viscosity profiling, particle size analysis, and preservative efficacy testing. This focused overview highlights practical formulation principles and stability pitfalls to help you design robust, patient-friendly suspensions. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the correct definition of a pharmaceutical suspension?

• A homogeneous solution of a drug in a liquid vehicle
• A heterogeneous system of insoluble particles dispersed in a liquid medium
• An emulsion of oil droplets in water
• A solid dosage form containing dispersed drug particles

Correct Answer: A heterogeneous system of insoluble particles dispersed in a liquid medium

Q2. Which is a primary advantage of suspensions for oral administration?

• They always provide sterile products without preservatives
• Improved bioavailability of poorly soluble drugs due to increased surface area
• They never require rheology modifiers
• They eliminate the need for stability testing

Correct Answer: Improved bioavailability of poorly soluble drugs due to increased surface area

Q3. Which of the following is a major disadvantage of suspensions?

• Complete chemical stability under all conditions
• Tendency to sediment and form a hard cake on storage
• They cannot contain preservatives
• They have inherently unlimited shelf life

Correct Answer: Tendency to sediment and form a hard cake on storage

Q4. What is the primary role of a suspending agent in a suspension?

• To increase the solubility of the drug in the vehicle
• To increase viscosity and reduce the rate of sedimentation
• To sterilize the formulation
• To cause irreversible caking of particles

Correct Answer: To increase viscosity and reduce the rate of sedimentation

Q5. Which statement correctly describes a flocculated suspension?

• Particles exist as tightly packed aggregates that are difficult to redisperse
• Flocculated systems form loose aggregates that remain easily redispersible
• They have no sedimentation and remain uniformly dispersed forever
• They require no wetting agents

Correct Answer: Flocculated systems form loose aggregates that remain easily redispersible

Q6. Sedimentation volume (F) is defined as:

• The viscosity of the suspension divided by particle diameter
• The ratio of the final settled volume of sediment to the original total volume
• The mass of drug in the supernatant after centrifugation
• The pH at which sedimentation is maximum

Correct Answer: The ratio of the final settled volume of sediment to the original total volume

Q7. According to Stoke’s law, which factor decreases the sedimentation rate of suspended particles?

• Increasing particle radius
• Decreasing continuous phase viscosity
• Increasing the density difference between particle and medium
• Decreasing particle radius

Correct Answer: Decreasing particle radius

Q8. What is the function of a wetting agent in suspension formulation?

• To increase crystallinity of the drug
• To reduce surface tension and promote particle wetting by the vehicle
• To act as a preservative
• To convert a flocculated system into a deflocculated one

Correct Answer: To reduce surface tension and promote particle wetting by the vehicle

Q9. Which of the following is a commonly used suspending agent?

• Sodium chloride
• Methylcellulose
• Sorbitol
• Calcium carbonate

Correct Answer: Methylcellulose

Q10. What does a high magnitude zeta potential typically indicate for a suspension?

• Greater tendency to flocculate
• Improved electrostatic repulsion and enhanced physical stability
• Immediate microbial contamination
• Higher likelihood of caking

Correct Answer: Improved electrostatic repulsion and enhanced physical stability

Q11. Why are preservatives usually added to aqueous suspensions?

• To increase viscosity
• To prevent microbial growth and ensure safety during storage
• To decrease particle size
• To accelerate sedimentation

Correct Answer: To prevent microbial growth and ensure safety during storage

Q12. Which technique is commonly used to reduce particle size for suspensions?

• Lyophilization
• Milling or micronization (e.g., jet milling, colloid milling)
• Direct compression
• Hot melt extrusion

Correct Answer: Milling or micronization (e.g., jet milling, colloid milling)

Q13. Which rheological behavior is most desirable for oral suspensions?

• Dilatant (shear-thickening) without redispersibility
• Pseudoplastic (shear-thinning) with thixotropic recovery
• Newtonian with no change on shear
• Highly elastic gel that cannot flow

Correct Answer: Pseudoplastic (shear-thinning) with thixotropic recovery

Q14. How is redispersibility of a suspension typically evaluated?

• By measuring pH only
• By visually observing ease of redispersion after standing and gentle shaking
• By measuring osmolarity
• By chromatographic assay of impurities

Correct Answer: By visually observing ease of redispersion after standing and gentle shaking

Q15. To reduce sedimentation rate, formulators commonly do which of the following?

• Increase particle size and decrease viscosity
• Decrease particle size and increase continuous phase viscosity
• Add strong oxidizers
• Remove preservatives

Correct Answer: Decrease particle size and increase continuous phase viscosity

Q16. Degree of flocculation (β) is defined as:

• The ratio of sedimentation volume of a flocculated suspension to that of a deflocculated suspension
• The pH at which flocculation occurs
• The absolute zeta potential value
• The concentration of suspending agent required for flocculation

Correct Answer: The ratio of sedimentation volume of a flocculated suspension to that of a deflocculated suspension

Q17. Addition of electrolytes to a suspension often causes which effect?

• Increase in zeta potential and better dispersion
• Decrease in zeta potential and promotion of flocculation
• Sterilization of the product
• Conversion to an emulsion

Correct Answer: Decrease in zeta potential and promotion of flocculation

Q18. What is ‘caking’ in the context of suspensions?

• Formation of a sticky film on the bottle cap
• Irreversible aggregation of sediment into a hard mass that resists redispersion
• Complete dissolution of particles into the vehicle
• Improved aesthetic appearance of the product

Correct Answer: Irreversible aggregation of sediment into a hard mass that resists redispersion

Q19. Which packaging feature is most useful for patient-friendly oral suspensions?

• Opaque blister packs
• Wide-mouth bottle with a dosing measure and tight-sealing cap
• Aluminum foil sachets that require reconstitution with organic solvents
• Sealed metal cans

Correct Answer: Wide-mouth bottle with a dosing measure and tight-sealing cap

Q20. Which of the following are common preservatives for aqueous suspensions?

• Benzalkonium chloride, methylparaben, sodium benzoate
• Calcium carbonate, magnesium stearate, talc
• Distilled water, ethanol, glycerin (no preservatives)
• Hydrochloric acid, sodium hydroxide, potassium sorbate

Correct Answer: Benzalkonium chloride, methylparaben, sodium benzoate

Q21. How does pH influence suspension stability?

• pH has no effect on suspensions
• pH can affect drug solubility, ionization, preservative activity, and particle charge
• Only affects color, not physical stability
• pH only matters for parenteral emulsions

Correct Answer: pH can affect drug solubility, ionization, preservative activity, and particle charge

Q22. Which instrument is most appropriate to measure the viscosity profile of a suspension?

• UV spectrophotometer
• Viscometer or rheometer
• pH meter
• Gas chromatograph

Correct Answer: Viscometer or rheometer

Q23. According to DLVO theory, what causes particle aggregation in suspensions?

• Covalent bonding between particles
• Van der Waals attraction overcoming electrostatic repulsion
• Excessive shear during manufacturing only
• High viscosity of the continuous phase

Correct Answer: Van der Waals attraction overcoming electrostatic repulsion

Q24. Which agents are typically used to induce flocculation?

• Strong oxidizing agents
• Electrolytes and certain polymers that reduce repulsive forces
• Nonionic solvents that dissolve the drug completely
• Bleaching agents

Correct Answer: Electrolytes and certain polymers that reduce repulsive forces

Q25. How do suspensions improve dissolution rate and possibly bioavailability?

• By forming a covalent complex with the drug
• By increasing the effective surface area of insoluble drug particles
• By permanently solubilizing the drug in the vehicle
• By chemically modifying the active ingredient

Correct Answer: By increasing the effective surface area of insoluble drug particles

Q26. Which advantage of suspensions is important for pediatric dosing?

• Fixed single-dose administration only
• Flexibility to adjust dose volume for different ages and weights
• They are always sugar-free
• Inability to mask unpleasant taste

Correct Answer: Flexibility to adjust dose volume for different ages and weights

Q27. What is a common patient-related disadvantage of suspensions?

• They are always tasteless
• Grittiness and mouthfeel may reduce patient acceptance and compliance
• They are invariably odorless
• They require no shaking before use

Correct Answer: Grittiness and mouthfeel may reduce patient acceptance and compliance

Q28. Which storage instruction is appropriate for many aqueous suspensions?

• Freeze to prolong shelf life
• Avoid freezing and excessive heat; store at controlled room temperature and shake before use
• Expose to direct sunlight to maintain homogeneity
• Store open to air to prevent pressure build-up

Correct Answer: Avoid freezing and excessive heat; store at controlled room temperature and shake before use

Q29. Which microbiological tests are essential for aqueous suspensions?

• Only sterility tests are required for all oral suspensions
• Preservative efficacy (challenge) test and microbial limit tests
• Gas chromatography for microbial metabolites
• No microbiological testing is needed for suspensions

Correct Answer: Preservative efficacy (challenge) test and microbial limit tests

Q30. What is levigation in suspension preparation?

• Dry blending of excipients without liquid
• Wet grinding of powder with a small amount of liquid to form a smooth paste and reduce particle size
• Sterilization by autoclaving
• Lyophilization to convert liquid to powder

Correct Answer: Wet grinding of powder with a small amount of liquid to form a smooth paste and reduce particle size

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