Evaluation of suppositories – parameters and methods MCQs With Answer

Introduction: Evaluation of suppositories involves systematic testing of physical, chemical and performance parameters to ensure safety, efficacy and quality. Key evaluation parameters include weight variation, content uniformity, liquefaction time, melting/softening point, disintegration, in vitro dissolution or drug release, hardness/fragility and microbial limits. Common analytical and instrumental methods used are USP/BP test procedures, differential scanning calorimetry (DSC), penetrometer, capillary (Thiele) melting-point method, HPLC/UV assay and dissolution apparatus selection. Understanding displacement value, base selection (fatty vs water-soluble), and stability testing is essential for formulation and QC of rectal, vaginal and urethral suppositories. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which parameter measures the time a suppository takes to liquefy at body temperature under standard test conditions?

• Disintegration time
• Liquefaction time
• Softening point
• Melting point

Correct Answer: Liquefaction time

Q2. Which official test ensures each suppository contains the intended amount of active pharmaceutical ingredient?

• Weight variation
• Disintegration test
• Content uniformity (assay)
• Softening point test

Correct Answer: Content uniformity (assay)

Q3. What does the displacement value of a drug indicate in suppository formulation?

• Viscosity change caused by the drug
• Amount of base displaced by a unit weight of drug
• Rate of dissolution of the drug
• Degree of drug degradation during melting

Correct Answer: Amount of base displaced by a unit weight of drug

Q4. Which temperature range is typical for the melting of cocoa butter (theobroma oil) used as a fatty suppository base?

• 10–20 °C
• 20–28 °C
• 30–36 °C
• 40–50 °C

Correct Answer: 30–36 °C

Q5. Which suppository base is water-soluble and often used for rapid drug release and ease of assay?

• Theobroma oil (cocoa butter)
• Polyethylene glycol (PEG) mixtures
• Witepsol (fatty base)
• Hard paraffin

Correct Answer: Polyethylene glycol (PEG) mixtures

Q6. Which instrument is commonly used to measure the penetration or firmness of a suppository base?

• UV spectrophotometer
• Penetrometer
• Disintegration tester
• pH meter

Correct Answer: Penetrometer

Q7. Which test evaluates uniformity of mass among individual suppositories in a batch?

• Content uniformity
• Weight variation test
• Melting point determination
• DSC analysis

Correct Answer: Weight variation test

Q8. Differential Scanning Calorimetry (DSC) is used in suppository evaluation primarily to assess which property?

• Microbial contamination
• Thermal behavior and polymorphism of base and drug
• pH stability
• Viscosity

Correct Answer: Thermal behavior and polymorphism of base and drug

Q9. Which test is most appropriate to predict in vivo drug availability from a suppository formulation?

• Disintegration test only
• Liquefaction time only
• In vitro dissolution or drug release study
• Softening point test only

Correct Answer: In vitro dissolution or drug release study

Q10. Why are glycerinated gelatin suppositories subject to microbiological limits testing?

• They are highly lipophilic
• They contain water and are susceptible to microbial growth
• They have very high melting points
• They are chemically inert

Correct Answer: They contain water and are susceptible to microbial growth

Q11. Which factor does NOT significantly influence drug release from a fatty (oleaginous) suppository base?

• Partition coefficient of the drug
• Melting behavior of the base
• Particle size of dispersed drug
• Ambient light exposure

Correct Answer: Ambient light exposure

Q12. Which analytical technique is most suitable for precise quantification of drug released from a suppository during dissolution testing?

• Thin-layer chromatography (TLC)
• High-performance liquid chromatography (HPLC)
• Penetrometry
• Softening point apparatus

Correct Answer: High-performance liquid chromatography (HPLC)

Q13. The term “softening point” in suppository evaluation refers to:

• The temperature at which the drug degrades
• The temperature at which the base softens and begins to flow
• The time required for a suppository to dissolve in water
• The pH at which the base becomes unstable

Correct Answer: The temperature at which the base softens and begins to flow

Q14. Which base type tends to provide more prolonged drug release and is less water-washable?

• Polyethylene glycol base
• Glycerinated gelatin base
• Fatty (oleaginous) bases like cocoa butter
• Hydrophilic gel bases

Correct Answer: Fatty (oleaginous) bases like cocoa butter

Q15. Eutectic formation between a drug and base in suppository formulation typically causes:

• Increase in melting point
• Decrease in melting point and softer product
• Improved microbial resistance
• Complete insolubility in all media

Correct Answer: Decrease in melting point and softer product

Q16. Which method is classically used to determine the melting point of a suppository base in the laboratory?

• Thiele tube (capillary) melting point method
• UV spectrophotometry
• Penetrometer test
• Microbial limit test

Correct Answer: Thiele tube (capillary) melting point method

Q17. Which physicochemical property of a drug strongly influences its release from a lipid suppository base?

• Boiling point
• Partition coefficient (lipophilicity)
• Optical rotation
• Color

Correct Answer: Partition coefficient (lipophilicity)

Q18. Which test assesses the tendency of a suppository to break or fragment under pressure during handling?

• Disintegration test
• Hardness/breaking strength test
• Melting point test
• Content uniformity

Correct Answer: Hardness/breaking strength test

Q19. For a suppository formulated with polyethylene glycol (PEG) base, which storage precaution is most important?

• Protect from moisture because PEGs are hygroscopic
• Store above 40 °C to keep them molten
• Expose to sunlight to reduce microbial load
• Keep in acidic conditions

Correct Answer: Protect from moisture because PEGs are hygroscopic

Q20. Which dissolution medium is commonly used as a starting point for in vitro release testing of rectal suppositories intended for systemic absorption?

• 0.1 N HCl
• Phosphate buffer pH 7.4
• Absolute ethanol
• Saturated saline only

Correct Answer: Phosphate buffer pH 7.4

Q21. Compatibility studies between drug and suppository base to detect interactions are commonly performed using which technique?

• FTIR (Fourier-transform infrared spectroscopy)
• Penetrometer
• Disintegration apparatus
• Softening point test

Correct Answer: FTIR (Fourier-transform infrared spectroscopy)

Q22. Which parameter specifically measures the time taken for a suppository to break up into smaller particles under test conditions?

• Liquefaction time
• Disintegration time
• Melting point
• Weight variation

Correct Answer: Disintegration time

Q23. Which approach helps to increase drug release from a lipid suppository base?

• Decrease drug solubility in the base
• Reduce drug particle size (micronization)
• Use a less soluble base only
• Avoid surfactants altogether

Correct Answer: Reduce drug particle size (micronization)

Q24. The primary reason to determine a suppository’s displacement value before moulding is to:

• Estimate melting point of the drug
• Calculate correct amount of base when drug replaces part of base volume
• Measure microbial load
• Determine hardness

Correct Answer: Calculate correct amount of base when drug replaces part of base volume

Q25. Which test would you perform to assess the physical stability of suppositories under accelerated temperature conditions?

• Microbial limit testing
• Accelerated stability studies (ICH conditions)
• Penetrometer test only at room temperature
• Immediate dissolution testing only

Correct Answer: Accelerated stability studies (ICH conditions)

Q26. Which base is known to undergo polymorphic changes that can affect melting behavior and should be evaluated for polymorphism?

• Polyethylene glycol (PEG)
• Cocoa butter (theobroma oil)
• Glycerinated gelatin
• Silicone oil

Correct Answer: Cocoa butter (theobroma oil)

Q27. In suppository dissolution testing, which modification can be used to maintain a hydrophobic surface exposure for fatty bases?

• Use of surfactant-free aqueous medium only
• Use of membrane or oil-water interface techniques to simulate rectal conditions
• Raising temperature to 60 °C
• Adding strong oxidizing agents

Correct Answer: Use of membrane or oil-water interface techniques to simulate rectal conditions

Q28. Which quality control test ensures that a batch of suppositories will not release significant amounts of drug before administration?

• Weight variation test only
• Leakage and surface integrity/visual inspection and in vitro release testing
• Softening point only
• Color comparison only

Correct Answer: Leakage and surface integrity/visual inspection and in vitro release testing

Q29. Which excipient class is commonly added to PEG-based suppositories to reduce brittleness and improve flexibility?

• Plasticizers such as glycerol or propylene glycol
• Strong acids
• Heavy metals
• Undeclared fragrances

Correct Answer: Plasticizers such as glycerol or propylene glycol

Q30. For regulatory acceptance, which compendial sources provide standardized methods for many suppository evaluation tests?

• Merck Index only
• USP (United States Pharmacopeia) and BP (British Pharmacopoeia)
• Random internet protocols only
• Individual manufacturer proprietary notes only

Correct Answer: USP (United States Pharmacopeia) and BP (British Pharmacopoeia)

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