Methods of preparation of suppositories MCQs With Answer

Introduction

Suppositories are solid dosage forms intended for rectal, vaginal, or urethral administration, prepared primarily by fusion (molding), compression, or hand-rolling. For B. Pharm students, mastering methods of preparation includes base selection (cocoa butter, polyethylene glycol, glycerinated gelatin), mold calibration, displacement factor calculations, tempering, lubrication, and techniques for incorporating soluble/insoluble, volatile, and thermolabile drugs. Key skills include preventing polymorphic changes in cocoa butter, controlling congealing temperature, minimizing sedimentation and air entrapment, and ensuring content uniformity. Practical knowledge of double-pour techniques, emulsification strategies, viscosity adjustment, and process controls enhances product quality, stability, and patient acceptability. This introduction emphasizes technique, troubleshooting, and pharmaceutic principles critical for compounding.

Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which method is most suitable for incorporating thermolabile and volatile drugs into suppositories?

• Fusion (molding) method
• Compression method
• Hand-rolling method
• Extrusion method

Correct Answer: Compression method

Q2. What is the primary purpose of tempering cocoa butter during fusion?

• To increase the melting point by adding waxes
• To avoid polymorphic transitions that cause soft suppositories
• To enhance solubility of hydrophilic drugs
• To reduce microbial growth

Correct Answer: To avoid polymorphic transitions that cause soft suppositories

Q3. The displacement factor (f) is used to calculate base requirement. Which formula is correct?

• Required base = blank base − (weight of drug ÷ f)
• Required base = blank base + (weight of drug × f)
• Required base = (blank base × f) − weight of drug
• Required base = weight of drug − (blank base ÷ f)

Correct Answer: Required base = blank base − (weight of drug ÷ f)

Q4. Hand-rolling (hand molding) is most appropriate when:

• Large-scale batches are needed
• Only water-soluble bases are used
• No special equipment is available and cocoa butter is the base
• High-precision, low-dose products are required

Correct Answer: No special equipment is available and cocoa butter is the base

Q5. Which base typically requires a preservative due to water content?

• Cocoa butter (Theobroma oil)
• Hydrogenated vegetable oil
• Glycerinated gelatin
• Hard fat (Witepsol)

Correct Answer: Glycerinated gelatin

Q6. When using polyethylene glycol (PEG) bases in flexible plastic molds, mold lubrication is generally:

• Always required with mineral oil
• Required only at high humidity
• Not required due to self-lubrication
• Required with water-glycerin mixture

Correct Answer: Not required due to self-lubrication

Q7. The “double-pour” technique mainly helps to reduce:

• Oxidative rancidity
• Contraction holes and sedimentation
• Drug degradation
• Microbial contamination

Correct Answer: Contraction holes and sedimentation

Q8. Which base exhibits good contraction on cooling and facilitates easy removal from metallic molds?

• Polyethylene glycol
• Glycerinated gelatin
• Cocoa butter
• PEG–glycerin blend

Correct Answer: Cocoa butter

Q9. Pouring at excessively high temperature during fusion primarily increases the risk of:

• Improved dose uniformity
• Low viscosity and increased sedimentation of suspended drug
• Rapid hardening without defects
• Enhanced polymorphic stability

Correct Answer: Low viscosity and increased sedimentation of suspended drug

Q10. What is mold calibration in suppository preparation?

• Determining optimal pour temperature
• Determining average blank mass per cavity for a specific base
• Determining hardness using a breaking tester
• Adjusting pH of the base

Correct Answer: Determining average blank mass per cavity for a specific base

Q11. To incorporate an aqueous solution into a fatty base by fusion, you should add:

• A w/o emulsifier such as sorbitan monostearate
• An o/w emulsifier such as polysorbate 80 only
• No emulsifier; water and fat spontaneously mix
• Sodium lauryl sulfate at high concentration

Correct Answer: A w/o emulsifier such as sorbitan monostearate

Q12. A key requirement for the compression method is that the mass must be:

• Highly fluid at room temperature
• Plastic and moldable without heating
• Completely aqueous
• Free-flowing powder

Correct Answer: Plastic and moldable without heating

Q13. Which is NOT an advantage of the compression method?

• Suitable for volatile drugs
• Eliminates heat exposure
• Produces glossy, seamless surfaces without polishing
• Reduces loss of volatile components

Correct Answer: Produces glossy, seamless surfaces without polishing

Q14. To avoid destroying the stable crystal form of cocoa butter during fusion, it is best to:

• Heat to about 34–36°C and avoid overheating
• Heat rapidly to 60°C then quench
• Microwave to boiling point
• Mix with high-melting PEGs and boil

Correct Answer: Heat to about 34–36°C and avoid overheating

Q15. Drug release from PEG suppositories occurs primarily by:

• Melting at body temperature
• Dissolution/erosion of the base
• Mechanical disintegration only
• Enzymatic degradation

Correct Answer: Dissolution/erosion of the base

Q16. The displacement factor (f) is best defined as:

• Weight of base that displaces 1 g of drug
• Weight of drug that displaces 1 g of base
• Ratio of drug solubility to base solubility
• Difference between densities of drug and base

Correct Answer: Weight of drug that displaces 1 g of base

Q17. Which technique best minimizes air bubble entrapment during fusion?

• Vigorous stirring to incorporate air
• Gentle stirring and pouring along the mold wall
• Pouring from a height to aerate the melt
• Rapid chilling immediately after pouring

Correct Answer: Gentle stirring and pouring along the mold wall

Q18. For a high-load insoluble drug in a fatty base, the most effective way to maintain uniformity is to:

• Pour at very high temperature for fluidity
• Stir continuously and pour near the congealing point
• Add excess surfactant regardless of compatibility
• Use no mixing to avoid air bubbles

Correct Answer: Stir continuously and pour near the congealing point

Q19. Which step best prevents “blooming” or surface crystallization in cocoa butter suppositories?

• Shock cooling directly in a freezer from the melt
• Controlled cooling at room temperature, then brief refrigeration
• Continuous heating at 45°C overnight
• Adding excess water

Correct Answer: Controlled cooling at room temperature, then brief refrigeration

Q20. For volatile oils added by fusion, the most appropriate approach is to:

• Add at the highest temperature for rapid mixing
• Add just before pouring, at a temperature close to congealing
• Add during tempering at 0–5°C
• Always convert to salts before adding

Correct Answer: Add just before pouring, at a temperature close to congealing

Q21. In metallic molds, which bases usually need mold lubrication?

• PEG bases only
• Cocoa butter and glycerinated gelatin
• Only glycerinated gelatin
• Only cocoa butter

Correct Answer: Cocoa butter and glycerinated gelatin

Q22. Which additive helps incorporate an aqueous drug solution into cocoa butter during fusion?

• Sorbitan monooleate (Span)
• Polyvinylpyrrolidone
• Citric acid
• Sodium chloride

Correct Answer: Sorbitan monooleate (Span)

Q23. To improve suspension stability of a dense powder in a fatty base, you would primarily:

• Decrease viscosity of the melt
• Increase viscosity and pour at lower temperature
• Add large amounts of water
• Use strong alkalizing agents

Correct Answer: Increase viscosity and pour at lower temperature

Q24. A common strategy to reduce rancidity in fatty bases during processing is to add:

• Antioxidants such as BHT or BHA
• High levels of sodium chloride
• Strong acids
• Only water

Correct Answer: Antioxidants such as BHT or BHA

Q25. Which equipment is specifically used in the compression method?

• Volumetric filling machine with heated reservoir
• Suppository die-and-punch press
• Spray dryer
• Rotary tablet press with standard punches

Correct Answer: Suppository die-and-punch press

Q26. The best way to ensure uniformity for a potent drug soluble in PEG base is to:

• Disperse as coarse powder
• Dissolve in melted PEG and mix thoroughly before pouring
• Mix with mineral oil before adding
• Add at the start of heating to boiling

Correct Answer: Dissolve in melted PEG and mix thoroughly before pouring

Q27. During mold filling, which practice helps minimize layer separation (“capping”)?

• Pour well above the melting point
• Pour just above the congealing temperature with steady stirring
• Refrigerate the mold before pouring
• Add ice to the melt

Correct Answer: Pour just above the congealing temperature with steady stirring

Q28. Which statement about cocoa butter polymorphism is correct?

• Overheating stabilizes the beta form
• Overheating converts to unstable forms with lower melting points
• Polymorphism is absent in cocoa butter
• Cooling rate has no effect on crystal form

Correct Answer: Overheating converts to unstable forms with lower melting points

Q29. The primary objective of mold calibration and use of displacement factor is to:

• Improve taste masking
• Accurately determine the base quantity for uniform mass
• Increase shelf life
• Reduce microbial load

Correct Answer: Accurately determine the base quantity for uniform mass

Q30. In the fusion method, what is the most appropriate action to ensure uniform fill across all cavities when using a suspension?

• Allow the mixture to stand before pouring
• Maintain gentle, continuous agitation and fill quickly
• Increase the mold temperature significantly
• Filter the suspension before pouring

Correct Answer: Maintain gentle, continuous agitation and fill quickly

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