Pellet manufacture involves specialized equipment and process control to convert powders into uniform, spherical multiparticulates for controlled release, taste masking, and enhanced flow. This concise overview highlights key pelletization equipment — high-shear granulators, extruders, spheronizers, pellet presses, and fluid-bed processors — and critical concepts like die design, pellet size distribution, coating systems, binder selection, porosity, friability, scale-up, and process validation. Understanding equipment operation, critical process parameters, troubleshooting, maintenance, and quality control tests is essential for B.Pharm students involved in formulation and production. Keywords: pelletization, spheronization, extruder, fluid bed coating, pellet press, pellet quality, process validation. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What is the primary objective of pelletization in pharmaceutical manufacturing?
- To produce tablets directly from powder
- To create uniform spherical multiparticulates for controlled release, taste masking, and improved flow
- To reduce API purity
- To increase moisture content of formulations
Correct Answer: To create uniform spherical multiparticulates for controlled release, taste masking, and improved flow
Q2. Which equipment is specifically designed to convert extrudates into nearly spherical pellets?
- High-shear granulator
- Spheronizer
- Fluid-bed dryer
- Pulverizer
Correct Answer: Spheronizer
Q3. What is the main function of a high-shear granulator in pellet manufacture?
- Air-drying and coating
- Wet massing and granule formation by intensive mixing and shear
- Cutting extrudates into pellets
- Measuring pellet hardness
Correct Answer: Wet massing and granule formation by intensive mixing and shear
Q4. The primary mechanism by which a fluid-bed processor functions is:
- Compression of powder between two dies
- Fluidization of particles using upward air flow for drying, granulation, or coating
- Mechanical cutting of slugs into pellets
- Magnetic separation of fines
Correct Answer: Fluidization of particles using upward air flow for drying, granulation, or coating
Q5. In extrusion-spheronization, what is the main role of the extruder?
- To coat pellets with polymeric film
- To produce cylindrical extrudates of controlled diameter from wet mass
- To dry the pellets using heated air
- To compress pellets into tablets
Correct Answer: To produce cylindrical extrudates of controlled diameter from wet mass
Q6. What is the typical correct sequence of steps in extrusion-spheronization?
- Spheronization → Extrusion → Drying
- Drying → Extrusion → Spheronization
- Wet massing → Extrusion → Spheronization → Drying
- Coating → Extrusion → Drying
Correct Answer: Wet massing → Extrusion → Spheronization → Drying
Q7. How does die diameter in an extruder primarily influence pellets?
- Coating thickness
- Pellet color
- Pellet diameter (size)
- API stability
Correct Answer: Pellet diameter (size)
Q8. Which parameter is most critical during spheronization for achieving high sphericity?
- Plate speed (rpm) and residence time in the spheronizer
- Inlet air humidity only
- API melting point
- Tablet press compression force
Correct Answer: Plate speed (rpm) and residence time in the spheronizer
Q9. Why is pellet coating performed in multiparticulate manufacture?
- To reduce pellet density only
- For taste masking, modified release, physical protection, and aesthetics
- To make pellets more porous
- To increase API degradation
Correct Answer: For taste masking, modified release, physical protection, and aesthetics
Q10. The principle of a pan (tumble) pelletizer is based on:
- Compression between two rollers
- Rotation of a shallow pan causing rolling and layering of material into pellets
- Magnetic aggregation of particles
- Spray-freeze drying
Correct Answer: Rotation of a shallow pan causing rolling and layering of material into pellets
Q11. Which analytical test is most commonly used to assess pellet size distribution?
- High-performance liquid chromatography (HPLC)
- Sieve analysis (sieving)
- pH measurement
- Thermogravimetric analysis (TGA)
Correct Answer: Sieve analysis (sieving)
Q12. Increasing compression force in a pellet press primarily affects which pellet attribute?
- Color change
- Density, hardness and friability
- Particle wettability only
- Melting point of API
Correct Answer: Density, hardness and friability
Q13. In fluid-bed coating, what effect does an excessively high spray rate have?
- Improves uniformity without risks
- Causes overwetting, agglomeration and poor coating uniformity
- Makes pellets completely porous
- Reduces drying time drastically without side effects
Correct Answer: Causes overwetting, agglomeration and poor coating uniformity
Q14. What is the primary function of a binder during pellet formation?
- To increase API solubility
- To provide interparticulate adhesion and help form strong granules/pellets
- To color the pellets
- To decrease pellet density only
Correct Answer: To provide interparticulate adhesion and help form strong granules/pellets
Q15. How does pellet porosity influence drug release?
- Higher porosity generally increases surface area and can accelerate drug release
- Porosity has no effect on release
- Higher porosity always slows release
- Porosity only affects color
Correct Answer: Higher porosity generally increases surface area and can accelerate drug release
Q16. A common cause of irregular or non-spherical pellets after spheronization is:
- Optimal moisture content and correct extrudate length
- Incorrect wet mass consistency or insufficient plasticity of the extrudate
- Excessive coating weight
- Too low API potency
Correct Answer: Incorrect wet mass consistency or insufficient plasticity of the extrudate
Q17. The L/D ratio of an extruder die mainly influences:
- Pellet color only
- Residence time, shaping and densification of the extrudate
- Coating polymer selection
- API chemical stability
Correct Answer: Residence time, shaping and densification of the extrudate
Q18. Which method is typically used to assess pellet friability?
- Friability testing using a tumbling drum followed by sieving and weight loss measurement
- HPLC assay only
- UV-visible spectroscopy
- Melting point determination
Correct Answer: Friability testing using a tumbling drum followed by sieving and weight loss measurement
Q19. During scale-up of a fluid-bed coating process, which parameter must be normalized to maintain coating uniformity?
- Spray rate relative to bed surface area and inlet air velocity
- API chemical name
- Color of coating solution
- Room lighting
Correct Answer: Spray rate relative to bed surface area and inlet air velocity
Q20. Which statement correctly distinguishes hot-melt extrusion from solvent-based extrusion in pellet manufacture?
- Hot-melt extrusion uses solvents while solvent-based extrusion is solvent-free
- Hot-melt extrusion melts polymer/mixture and is solvent-free, while solvent-based extrusion uses liquids to plasticize the mass
- Both methods always require subsequent freeze-drying
- Hot-melt extrusion cannot be used for controlled release systems
Correct Answer: Hot-melt extrusion melts polymer/mixture and is solvent-free, while solvent-based extrusion uses liquids to plasticize the mass
Q21. What is the role of a chopper or mill in a fluid-bed processor during pelletization?
- To increase air humidity
- To break large agglomerates and control particle size
- To color the pellets
- To measure pH of coating solution
Correct Answer: To break large agglomerates and control particle size
Q22. Compared to the original powder blend, pellets generally exhibit which of the following bulk properties?
- Lower bulk density and poorer flow
- Higher bulk density and improved flowability
- Increased hygroscopicity only
- No change in handling properties
Correct Answer: Higher bulk density and improved flowability
Q23. Typical desirable pellet size range for oral multiparticulate dosage forms is approximately:
- 10–50 µm
- 300–1400 µm
- 5–20 mm
- 100–200 nm
Correct Answer: 300–1400 µm
Q24. Which measurement is most commonly used to monitor coating build-up on pellets during processing?
- Weight gain percentage (coating weight gain) and thickness measurements
- API melting point
- UV absorbance of the core
- Nitrogen adsorption only
Correct Answer: Weight gain percentage (coating weight gain) and thickness measurements
Q25. The most common cause of pellet agglomeration during fluid-bed coating is:
- Too low spray rate and high inlet air temperature
- Excessive spray rate, large droplets, or insufficient drying capacity
- Using too small a spheronizer
- Excessive pellet porosity only
Correct Answer: Excessive spray rate, large droplets, or insufficient drying capacity
Q26. Which equipment is typically used to determine pellet size distribution and remove out-of-spec fines or oversized particles?
- Vibratory sieve shaker (sieving)
- Rotary tablet press
- Hot-melt extruder
- UV spectrophotometer
Correct Answer: Vibratory sieve shaker (sieving)
Q27. The texture and rib pattern of the spheronizer friction plate most directly affect:
- Rate of API degradation
- Pellet sphericity and surface smoothness
- Coating polymer molecular weight
- Batch recording in GMP logs
Correct Answer: Pellet sphericity and surface smoothness
Q28. Which instrument is commonly used to measure pellet crushing strength (hardness)?
- Texture analyzer or dedicated crushing strength tester
- pH meter
- Gas chromatograph
- Thermostat
Correct Answer: Texture analyzer or dedicated crushing strength tester
Q29. Which of the following is least critical when optimizing a fluid-bed coating process for uniform film formation?
- Spray droplet size and spray rate
- Inlet air temperature and airflow
- Coating solution viscosity and solids content
- Color of the operator’s lab coat
Correct Answer: Color of the operator’s lab coat
Q30. For regulatory compliance and consistent pellet quality, which validation activity is essential for pellet manufacturing equipment?
- Process validation including equipment qualification (IQ/OQ/PQ) and cleaning validation
- Only color matching validation
- Validating office seating arrangements
- Only supplier auditing without process validation
Correct Answer: Process validation including equipment qualification (IQ/OQ/PQ) and cleaning validation
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