Tablet coating is a critical area in pharmaceutics that covers methods such as film coating, sugar coating, enteric coating, compression coating, and microencapsulation. B.Pharm students must understand coating materials (HPMC, ethylcellulose, Eudragit), plasticizers, solvents (aqueous vs organic), coating equipment (perforated pans, fluidized bed/Würster), process parameters (spray rate, inlet air temperature, atomization), common defects (peeling, mottling, orange peel) and quality control tests (weight gain, dissolution, uniformity). This introduction emphasizes mechanisms, troubleshooting, and scale-up considerations to build practical competence in tablet coating. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What is the primary collective purpose of tablet coating methods?
- Improve tablet appearance only
- Control drug release only
- Protect API from environment only
- All of the above
Correct Answer: All of the above
Q2. Which polymer is most commonly used as a film-former in aqueous film coating?
- Hydroxypropyl methylcellulose (HPMC)
- Sucrose
- Gelatin
- Talc
Correct Answer: Hydroxypropyl methylcellulose (HPMC)
Q3. Which of the following are enteric coating polymers used to prevent drug release in the stomach?
- Hydroxypropyl methylcellulose phthalate (HPMCP)
- Eudragit L
- Eudragit S
- All of the above
Correct Answer: All of the above
Q4. Which industrial equipment is commonly used for continuous film coating of tablets with efficient drying?
- Compression molding press
- Perforated coating pan (perforated drum)
- Tablet embossing machine
- Rotary granulator
Correct Answer: Perforated coating pan (perforated drum)
Q5. Which process parameter primarily controls the solvent evaporation rate during spray coating?
- Spray rate
- Inlet air temperature
- Atomization air pressure
- Coating pan speed
Correct Answer: Inlet air temperature
Q6. What is the main purpose of adding a plasticizer to a coating formulation?
- Increase polymer film flexibility and prevent cracking
- Increase polymer brittleness and hardness
- Act as a primary colorant
- Reduce tablet dissolution rate drastically
Correct Answer: Increase polymer film flexibility and prevent cracking
Q7. Typical coating weight gain (%) for immediate-release film-coated tablets used mainly for appearance and light taste masking is usually:
- 1–2%
- 3–6%
- 10–20%
- Over 30%
Correct Answer: 3–6%
Q8. The coating defect known as “orange peel” is most often caused by:
- Too rapid solvent evaporation during coating
- Excessive relative humidity in the coating room
- Insufficient plasticizer concentration only
- Use of enteric polymers only
Correct Answer: Too rapid solvent evaporation during coating
Q9. Which is a direct method to assess individual tablet coating uniformity?
- Dissolution test of a pooled sample
- Weight gain measurement of individual tablets
- Hardness test
- Friability test
Correct Answer: Weight gain measurement of individual tablets
Q10. A key advantage of fluidized bed (Würster) coating compared to conventional pan coating is:
- Lower initial equipment cost
- Better coating of multiparticulates and faster drying
- No need for polymer binders
- Simpler scale-up for large tablets
Correct Answer: Better coating of multiparticulates and faster drying
Q11. Which solvent system is preferred to minimize flammability and environmental hazards during coating?
- Organic solvent-based systems (e.g., methylene chloride)
- Aqueous-based coating systems
- Pure ethanol systems
- Chloroform-based systems
Correct Answer: Aqueous-based coating systems
Q12. Compression (press) coating is primarily used in tablet manufacturing to:
- Improve tablet gloss for over-the-counter products
- Separate incompatible ingredients or produce multilayer release profiles
- Replace film coating for taste masking in all cases
- Reduce the need for polymer binders
Correct Answer: Separate incompatible ingredients or produce multilayer release profiles
Q13. The Wurster process is a fluid-bed coating technique especially suitable for coating:
- Large monolithic tablets only
- Pellets, beads and granules (multiparticulates)
- Compressed sugar-coated tablets only
- Microcrystalline cellulose cores exclusively
Correct Answer: Pellets, beads and granules (multiparticulates)
Q14. Which of the following polymers is commonly used for enteric protection to delay release until intestinal pH?
- Polyethylene glycol (PEG) alone
- Ethylcellulose
- Eudragit L (methacrylic acid copolymer)
- Talc powder
Correct Answer: Eudragit L (methacrylic acid copolymer)
Q15. Which analytical technique is commonly used to visualize and measure coating film thickness and surface morphology?
- High-performance liquid chromatography (HPLC)
- Scanning electron microscopy (SEM)
- Ultraviolet spectroscopy (UV)
- Karl Fischer titration
Correct Answer: Scanning electron microscopy (SEM)
Q16. Droplet size generated during spray coating is primarily influenced by which factors?
- Atomization air pressure and nozzle type
- Tablet hardness and friability
- Coating pan color and finish
- Core dissolution rate
Correct Answer: Atomization air pressure and nozzle type
Q17. Which of the following is a commonly used plasticizer in coating formulations?
- Triethyl citrate
- Titanium dioxide
- Magnesium stearate
- Microcrystalline cellulose
Correct Answer: Triethyl citrate
Q18. Eudragit L-type enteric polymers typically dissolve at pH values above approximately:
- pH 3.0
- pH 4.0
- pH 6.0
- pH 8.5
Correct Answer: pH 6.0
Q19. The coating defect “twinning” (tablets sticking together) is mainly due to:
- Excessive tablet lubricity
- Excessive tackiness of the coating surface during processing
- Overuse of opacifier pigments
- High tablet hardness
Correct Answer: Excessive tackiness of the coating surface during processing
Q20. Which core tablet property most significantly affects adhesion of a polymer coating?
- Tablet imprint depth only
- Surface porosity and roughness
- Color of the core
- Label claim strength
Correct Answer: Surface porosity and roughness
Q21. During scale-up of a coating process, which ratio is most critical to maintain similarity in film formation between batches?
- Coating pan diameter to tablet diameter
- Spray-to-bed ratio (spray rate per mass of tablets)
- Number of tablets per coating pan revolution
- Operator shift length
Correct Answer: Spray-to-bed ratio (spray rate per mass of tablets)
Q22. Which polymer is commonly used as a water-insoluble barrier for sustained/controlled release coatings?
- Hydroxypropyl methylcellulose (HPMC)
- Ethylcellulose
- Sucrose
- Gelatin
Correct Answer: Ethylcellulose
Q23. For effective taste masking of a bitter API, which coating approach is most appropriate?
- Thin aesthetic film coating with only colorant
- Film coating using a water-insoluble or pH-independent taste-masking polymer
- Omitting coating and reducing dose
- Using talc as a coating layer
Correct Answer: Film coating using a water-insoluble or pH-independent taste-masking polymer
Q24. Which pigment/opacifier is widely used to provide opacity and whiteness in tablet coatings?
- Titanium dioxide
- Magnesium stearate
- Sodium chloride
- Polyethylene glycol
Correct Answer: Titanium dioxide
Q25. Coating efficiency in a spray-coating operation refers to:
- The ratio of tablets coated per hour to pan capacity
- The ratio of solid mass deposited on tablets to the solid mass sprayed
- The percentage of tablets passing dissolution
- The time taken to reach final gloss
Correct Answer: The ratio of solid mass deposited on tablets to the solid mass sprayed
Q26. The principal safety hazard associated with organic solvent-based coating is:
- Excessive drying efficiency
- Flammability and toxicity hazards
- Improved product shelf life
- Guaranteed uniform coating
Correct Answer: Flammability and toxicity hazards
Q27. Which coating defect is most likely when tablet cores have low hardness?
- Mottling only
- Chipping and edge damage
- Over-opacity
- Excessive gloss
Correct Answer: Chipping and edge damage
Q28. “Mottling” in coated tablets is typically caused by:
- Poorly dispersed pigments and pigment migration leading to uneven color
- Too much plasticizer making films too flexible
- Using excessive coating weight only
- High tablet hardness preventing adhesion
Correct Answer: Poorly dispersed pigments and pigment migration leading to uneven color
Q29. For low-dose drugs where dose uniformity is critical, which coating approach is often most suitable?
- Bulk film coating of large tablets without segregation control
- Coating multiparticulate pellets in a fluidized-bed for uniform distribution
- Sugar coating only on compressed cores
- Using talc spraying without polymer
Correct Answer: Coating multiparticulate pellets in a fluidized-bed for uniform distribution
Q30. Which inline analytical method can monitor coating mass or film build-up in real time during coating?
- Offline HPLC assay after coating
- Near-infrared (NIR) spectroscopy
- Visual inspection only
- Tap density measurement during coating
Correct Answer: Near-infrared (NIR) spectroscopy
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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