Pellets are small, free-flowing, spherical agglomerates used in multiparticulate drug delivery to improve flow, content uniformity, taste masking, and modified or sustained release. Key pelletization techniques include extrusion-spheronization, layer coating, and fluid-bed granulation; common excipients are microcrystalline cellulose, povidone, HPMC and ethylcellulose for release control. Critical attributes—particle size distribution, sphericity, porosity, friability and coating integrity—govern drug release, stability and manufacturability. Understanding equipment (extruder, spheronizer, fluid-bed coater), formulation variables and in-process controls is essential for B.Pharm students preparing for industry or research. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What is the primary definition of a pharmaceutical pellet?
- A large monolithic tablet for single-unit dosing
- A small, spherical free-flowing agglomerate used in multiparticulate drug delivery
- A liquid suspension of micronized drug particles
- A film-coated capsule shell
Correct Answer: A small, spherical free-flowing agglomerate used in multiparticulate drug delivery
Q2. Which of the following is a major advantage of multiparticulate pellets over single-unit tablets?
- Higher risk of dose dumping
- More variable gastric emptying
- Improved dose uniformity and reduced local irritation
- Always lower manufacturing cost
Correct Answer: Improved dose uniformity and reduced local irritation
Q3. Which technique is most commonly used to produce spherical pellets with good shape and narrow size distribution?
- Direct compression
- Hot-melt extrusion without spheronization
- Extrusion-spheronization
- Spray drying of organic solutions only
Correct Answer: Extrusion-spheronization
Q4. In extrusion-spheronization, which excipient is most frequently used to aid spheronization and matrix formation?
- Lactose monohydrate
- Microcrystalline cellulose (MCC)
- Sodium chloride
- Magnesium stearate
Correct Answer: Microcrystalline cellulose (MCC)
Q5. What is the role of a spheronizer in pellet manufacture?
- To dry pellets at high temperature
- To impart rounded shape and uniform size by frictional rounding
- To coat pellets with polymer films
- To micronize the active pharmaceutical ingredient
Correct Answer: To impart rounded shape and uniform size by frictional rounding
Q6. Which process parameter most strongly influences pellet size during extrusion?
- Binder molecular weight only
- Extrudate die diameter and extrusion speed
- Coating polymer type
- Final package design
Correct Answer: Extrudate die diameter and extrusion speed
Q7. Fluid-bed coating is preferred for pellets because it provides which key benefit?
- Poor solvent removal and long drying times
- Uniform coating, efficient drying and scale-up flexibility
- Elimination of the need for binders in formulation
- Guaranteed zero friability without testing
Correct Answer: Uniform coating, efficient drying and scale-up flexibility
Q8. Which property of pellets is most critical for consistent coating thickness and content uniformity?
- Color of the drug substance
- Sphericity and narrow particle size distribution
- Tablet punching force
- Packaging label design
Correct Answer: Sphericity and narrow particle size distribution
Q9. Which test is commonly used to evaluate pellet friability?
- Hardness tester for tablets
- USP friability test for tablets without modification
- Dedicated pellet friability tester or modified tumbling test with sieving
- pH titration
Correct Answer: Dedicated pellet friability tester or modified tumbling test with sieving
Q10. How does pellet porosity generally affect drug release rate?
- Higher porosity usually slows drug release due to trapping
- Higher porosity generally increases drug release by allowing faster penetration of dissolution medium
- Porosity has no effect on release
- Lower porosity always makes pellets float
Correct Answer: Higher porosity generally increases drug release by allowing faster penetration of dissolution medium
Q11. Which polymer is commonly used for sustained-release coating of pellets?
- Polyethylene glycol 400 (low MW liquid)
- Ethylcellulose or Eudragit RS/RL grade polymers
- Sucrose syrup
- Sodium chloride
Correct Answer: Ethylcellulose or Eudragit RS/RL grade polymers
Q12. What is the main purpose of core starter seeds (nonpareil seeds) in pellet layering?
- To act as disintegrants inside the pellet
- To provide a small, solid nucleus for successive coating/layering and size build-up
- To increase pellet porosity deliberately
- To function as primary active pharmaceutical ingredients
Correct Answer: To provide a small, solid nucleus for successive coating/layering and size build-up
Q13. Which binder is frequently used in pellet wet massing for extrusion-spheronization?
- Povidone (PVP) or aqueous solutions of hydroxypropyl methylcellulose (HPMC)
- Silica gel
- Magnesium stearate powder only
- Concentrated hydrochloric acid
Correct Answer: Povidone (PVP) or aqueous solutions of hydroxypropyl methylcellulose (HPMC)
Q14. Which is NOT a common mechanism for modifying drug release from pellets?
- Diffusion through a polymeric coating
- Reservoir dissolution followed by diffusion through coating pores
- Immediate precipitation of drug on ingestion for faster release
- Use of lipid matrices to retard release
Correct Answer: Immediate precipitation of drug on ingestion for faster release
Q15. During pellet coating, which factor most often causes agglomeration of pellets?
- Excessively high spray rate or inappropriate binder level causing tackiness
- Using inert coating polymers
- Low inlet air temperature with no spray
- Exclusion of solvent from coating suspension
Correct Answer: Excessively high spray rate or inappropriate binder level causing tackiness
Q16. Typical target size range for oral pellets to ensure acceptable flow and gastric emptying is:
- 10–50 µm
- 100–200 µm only
- 300–1500 µm (commonly 300–1000 µm)
- 5–10 mm
Correct Answer: 300–1500 µm (commonly 300–1000 µm)
Q17. Which analytical method provides direct visualization of pellet sphericity and coating uniformity?
- Laser diffraction particle sizing alone
- Optical microscopy or scanning electron microscopy (SEM)
- pH meter
- Titration with sodium hydroxide
Correct Answer: Optical microscopy or scanning electron microscopy (SEM)
Q18. Why is batch-to-batch reproducibility especially important for pellet formulations?
- Pellets are easier to change after marketing without regulatory notice
- Because small variations in size, coating or porosity can significantly alter release and bioavailability
- Pellets have no in vivo variability so reproducibility is irrelevant
- Only color needs to be consistent for patient acceptance
Correct Answer: Because small variations in size, coating or porosity can significantly alter release and bioavailability
Q19. Which drying method is most suitable for heat-sensitive drugs in pellet manufacture?
- High-temperature tray drying without airflow control
- Fluid-bed drying with controlled inlet temperatures and rapid solvent removal
- Open-air sun drying
- Prolonged oven drying at high temperature
Correct Answer: Fluid-bed drying with controlled inlet temperatures and rapid solvent removal
Q20. What is the main risk when compressing coated pellets into tablets (pellet-in-tablet approach)?
- Pellet colors becoming darker
- Rupture of pellets and damage to coating leading to altered release
- Immediate dissolution of coating into the granulation fluid
- Complete transformation of polymer chemistry
Correct Answer: Rupture of pellets and damage to coating leading to altered release
Q21. Which excipient is commonly added to improve pellet flow during processing?
- Microcrystalline cellulose for matrix and flow
- Excessive povidone causing stickiness
- Large quantities of talc only as lubricant in wet mass
- Pure sucrose crystals to dissolve in aqueous mass
Correct Answer: Microcrystalline cellulose for matrix and flow
Q22. For taste-masking immediate-release pellets, which approach is most appropriate?
- Coating drug-containing pellets with an insoluble polymer only
- Applying a water-soluble sweet coating that dissolves in the stomach instantly
- Using a polymeric barrier coat or lipid coat that prevents dissolution in the oral cavity but releases in the stomach
- Leaving drug uncoated and relying on mouthwash
Correct Answer: Using a polymeric barrier coat or lipid coat that prevents dissolution in the oral cavity but releases in the stomach
Q23. Which parameter is LEAST relevant when designing a sustained-release pellet coating?
- Coating polymer permeability
- Coating thickness and uniformity
- Mechanical integrity of coating (friability)
- Color of coating pigment with no effect on film properties
Correct Answer: Color of coating pigment with no effect on film properties
Q24. Which of the following is a common in-process control test during pellet manufacture?
- Blood compatibility test
- Particle size distribution by sieving or laser diffraction
- Accelerated stability for 6 months in-process
- Final patient acceptability questionnaire
Correct Answer: Particle size distribution by sieving or laser diffraction
Q25. How does pellet bulk density influence oral dosage form behavior?
- Higher bulk density causes pellets to instantly degrade
- Bulk density affects flow, packing in capsules/tablets and gastric residence time
- Bulk density determines chemical stability of API exclusively
- Bulk density is irrelevant for manufacturing
Correct Answer: Bulk density affects flow, packing in capsules/tablets and gastric residence time
Q26. Which coating parameter change will generally slow drug release from coated pellets?
- Reducing polymer molecular weight while keeping thickness constant
- Decreasing coating thickness
- Increasing coating thickness or using less-permeable polymer
- Removing the coating completely
Correct Answer: Increasing coating thickness or using less-permeable polymer
Q27. Powder layering versus solution/suspension layering differs mainly in that powder layering:
- Builds layers by depositing dry powder onto seeds using a binder solution to tack, allowing faster build-up without dissolving drug
- Requires dissolving the entire drug in an organic solvent
- Is only suitable for biologics with extreme heat sensitivity
- Always produces non-spherical particles
Correct Answer: Builds layers by depositing dry powder onto seeds using a binder solution to tack, allowing faster build-up without dissolving drug
Q28. Which factor is critical to prevent migration of drug from core to coating during pellet production?
- Using extremely high coating temperatures to volatilize drug
- Selection of compatible solvents, appropriate drying conditions and barrier layers if necessary
- Adding salt to the coating suspension indiscriminately
- Leaving pellets in open air for weeks before coating
Correct Answer: Selection of compatible solvents, appropriate drying conditions and barrier layers if necessary
Q29. Which evaluation is essential to demonstrate equivalence of pellet lots in regulatory submissions?
- Visual color preference by patients only
- Comparative dissolution profiling, content uniformity and critical quality attributes like size distribution and friability
- Only microbial testing is required for identical APIs
- No testing is required if the manufacturer is established
Correct Answer: Comparative dissolution profiling, content uniformity and critical quality attributes like size distribution and friability
Q30. Which formulation strategy can be used to prepare gastroretentive pellets that prolong gastric residence?
- Designing very dense pellets that sink rapidly to the antrum
- Using low-density, floating matrix or expandable coatings to increase buoyancy
- Maximizing pellet hardness only
- Coating with water-soluble polymer to ensure immediate emptying
Correct Answer: Using low-density, floating matrix or expandable coatings to increase buoyancy
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.
Mail- Sachin@pharmacyfreak.com