Pelletization is a key unit operation in pharmaceutical technology that converts fine powders into free‑flowing, spherical aggregates (pellets) suitable for capsule filling, tableting, and modified‑release formulations. This process—using techniques like extrusion–spheronization, pan (disc) pelletizing, and layered pelletization—depends on controlled nucleation, accretion, and consolidation influenced by binders, granulation liquid, equipment speed, and drying method. Critical quality attributes include size distribution, sphericity, porosity, mechanical strength, and surface morphology, which affect dissolution, content uniformity, and stability. Mastery of process variables, troubleshooting common defects, and appropriate analytical tests is essential for formulation scientists. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What is the primary objective of pelletization in pharmaceutical manufacturing?
- To convert liquids into semi-solids
- To produce spherical, free‑flowing granules for controlled dosing
- To improve powder color and odor
- To sterilize powders before tableting
Correct Answer: To produce spherical, free‑flowing granules for controlled dosing
Q2. Which mechanism is NOT typically involved in pellet growth during wet pelletization?
- Nucleation
- Accretion
- Consolidation
- Osmotic shocking
Correct Answer: Osmotic shocking
Q3. Which technique is best described as blending, wet massing, extrusion, spheronization, drying, and sizing?
- Pan pelletizing
- Fluidized bed layering
- Extrusion–spheronization
- Spray drying
Correct Answer: Extrusion–spheronization
Q4. In pan (disc) pelletizing, which parameter most directly affects pellet size?
- Pan angle and rotational speed
- Final drying temperature
- Type of lubricant used in tableting
- Tablet compression force
Correct Answer: Pan angle and rotational speed
Q5. Which binder property is most important for forming strong, coherent wet masses during pelletization?
- High melting point
- Appropriate viscosity and adhesive strength
- Strong alkalinity
- Low molecular weight volatile solvents
Correct Answer: Appropriate viscosity and adhesive strength
Q6. Which equipment is commonly used for layered (solution or suspension) pelletization?
- Rotary tablet press
- Fluidized bed coater/pelletizer
- High-shear granulator only
- Lyophilizer
Correct Answer: Fluidized bed coater/pelletizer
Q7. What is the role of spheronization in extrusion–spheronization?
- To dry pellets at high temperature
- To round extrudates into near‑spherical pellets by friction and rolling
- To coat pellets with polymers
- To mix active ingredients with filler
Correct Answer: To round extrudates into near‑spherical pellets by friction and rolling
Q8. Which attribute of pellets most strongly influences release rate for immediate release formulations?
- Color
- Porosity and surface area
- Production date
- Packaging material
Correct Answer: Porosity and surface area
Q9. Which test assesses mechanical robustness of pellets to simulate handling and coating stresses?
- Viscosity measurement
- Friability testing
- Thermogravimetric analysis
- pH titration
Correct Answer: Friability testing
Q10. High binder spray rate during layering commonly causes which defect?
- Excessive sphericity
- Agglomeration and sticking
- Improved dispersibility
- Reduced particle density only
Correct Answer: Agglomeration and sticking
Q11. What is the significance of pellet size distribution (PSD) in final dosage forms?
- It only affects color uniformity
- PSD affects content uniformity, release profile, and flow properties
- PSD determines tablet hardness exclusively
- PSD is irrelevant for coated pellets
Correct Answer: PSD affects content uniformity, release profile, and flow properties
Q12. Which measurement indicates pellet sphericity quantitatively?
- Aspect ratio or circularity from image analysis
- Melting point
- Intrinsic viscosity
- pKa of the drug
Correct Answer: Aspect ratio or circularity from image analysis
Q13. During drying of pellets, why is controlled drying rate important?
- To maximize residual solvent content
- To avoid cracking, shrinkage, and loss of mechanical strength
- To cause complete amorphization of the API
- To change the drug’s chemical identity
Correct Answer: To avoid cracking, shrinkage, and loss of mechanical strength
Q14. Which excipient is commonly used as a spheronization aid and filler in extrusion–spheronization?
- Microcrystalline cellulose (MCC)
- Magnesium stearate exclusively
- Polyethylene glycol 4000 solely
- Sodium chloride
Correct Answer: Microcrystalline cellulose (MCC)
Q15. What is the main advantage of pellet dosage forms over conventional granules?
- Pellets always eliminate the need for coating
- Improved uniformity, reduced dose dumping, and flexibility for modified release
- Pellets are cheaper to produce in all cases
- Pellets never require drying
Correct Answer: Improved uniformity, reduced dose dumping, and flexibility for modified release
Q16. Which parameter in a pan pelletizer helps control wetting and layering efficiency?
- Binder spray position and spray rate
- Ambient air pressure inside the capsule
- Tablet compression dwell time
- Color of the pan
Correct Answer: Binder spray position and spray rate
Q17. What effect does increasing pellet porosity generally have on drug release?
- Slower release due to pore closure
- Faster release because of greater solvent penetration
- No effect on release kinetics
- Causes immediate chemical degradation
Correct Answer: Faster release because of greater solvent penetration
Q18. Which troubleshooting measure is appropriate if pellets show excessive dusting after drying?
- Increase drying temperature drastically
- Adjust binder concentration or apply a light polymer coating
- Replace API with a larger molecule
- Reduce pellet porosity by adding volatile solvents
Correct Answer: Adjust binder concentration or apply a light polymer coating
Q19. Which polymer is commonly used for sustained‑release coatings on pellets?
- Ethylcellulose
- Sodium chloride
- Magnesium stearate
- Citric acid
Correct Answer: Ethylcellulose
Q20. In extrusion–spheronization, what is the consequence of an overly dry wet mass during extrusion?
- Improved spheronization yield
- Poor extrusion, irregular extrudates, and low sphericity
- Faster drying time with no side effects
- Enhanced binder adhesion
Correct Answer: Poor extrusion, irregular extrudates, and low sphericity
Q21. What is the purpose of size classification (sieving) after pellet production?
- To selectively remove API from pellets
- To obtain a defined size fraction for consistent dosing and coating
- To change the chemical composition of pellets
- To sterilize the pellets
Correct Answer: To obtain a defined size fraction for consistent dosing and coating
Q22. Which analytical technique is frequently used to study pellet surface morphology?
- Scanning electron microscopy (SEM)
- pH meter
- UV–Vis spectroscopy
- Karl Fischer titration
Correct Answer: Scanning electron microscopy (SEM)
Q23. What does a high SPAN value indicate about pellet size distribution?
- Very narrow size distribution
- Broad size distribution with wide variability
- Complete uniformity of particle shape
- Exclusive presence of nanoparticles
Correct Answer: Broad size distribution with wide variability
Q24. Which drying method is most suitable for heat‑sensitive pellets?
- Tray drying at very high temperatures
- Fluidized bed drying with controlled temperature and gentle air
- Direct flame drying
- Autoclave sterilization
Correct Answer: Fluidized bed drying with controlled temperature and gentle air
Q25. Which factor primarily influences the density and flowability of pellets?
- Ambient light intensity during production
- Compression force during tablet pressing only
- Particle size, porosity, and surface roughness
- Type of glassware used
Correct Answer: Particle size, porosity, and surface roughness
Q26. Layered pelletization in a fluidized bed often uses which mode to apply coating solution?
- Top-spray or Wurster bottom-spray modes
- Tablet press mode
- Lyophilization mode
- Rotary evaporation mode
Correct Answer: Top-spray or Wurster bottom-spray modes
Q27. Which issue is indicated by pellets with rough, pitted surfaces after drying?
- Excessive binder causing smoothness
- Too rapid drying causing surface collapse and voids
- Perfect formulation and process control
- Lack of API in the formulation
Correct Answer: Too rapid drying causing surface collapse and voids
Q28. For multiparticulate modified‑release systems, why are pellets preferred?
- They always eliminate inter-patient variability
- They allow dose flexibility, reduce local GI irritation, and provide predictable release
- They ensure immediate release only
- They are easier to sterilize than tablets
Correct Answer: They allow dose flexibility, reduce local GI irritation, and provide predictable release
Q29. Which change would typically reduce pellet friability?
- Decrease binder concentration
- Improve binder adhesion or increase drying consolidation
- Increase porosity drastically
- Remove all spheronization steps
Correct Answer: Improve binder adhesion or increase drying consolidation
Q30. Which of the following is an advantage of using multiparticulate pellets in capsule formulations?
- Higher risk of dose dumping compared with single units
- Uniform GI transit, reduced variability, and ability to mix pellets for combination therapy
- Incompatibility with coatings
- Inability to achieve modified release
Correct Answer: Uniform GI transit, reduced variability, and ability to mix pellets for combination therapy
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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