Tablet Coating Processes MCQs With Answer

Tablet Coating Processes MCQs With Answer

The tablet coating process is a vital unit operation in pharmaceutical production, combining formulation science, engineering and quality control to produce safe, efficacious and attractive oral dosage forms. This blog focuses on core concepts M.Pharm students must master: coating types (sugar, film, enteric, compression), coating materials (polymers, plasticizers, pigments), common coaters and process parameters, troubleshooting coating defects, analytical tests, and scale-up considerations. The following 20 MCQs with answers probe detailed, application-oriented knowledge—spray atomization, drying dynamics, solvent risks, coating weight calculations, and defect causes—helping postgraduate students prepare for exams and practical lab work by reinforcing theory and decision-making in real production scenarios.

Q1. Which of the following best describes the primary objectives of tablet coating?

• Mask unpleasant taste and odor only
• Improve appearance and ease of swallowing only
• Provide moisture and light protection only
• Mask taste, improve appearance, provide protection and modify release characteristics

Correct Answer: Mask taste, improve appearance, provide protection and modify release characteristics

Q2. Which list correctly identifies the common industrial types of tablet coating used in pharmaceutical manufacturing?

• Dip coating, electroplating, spray drying
• Film coating, sugar coating, enteric coating, compression coating
• Lyophilization, granulation coating, melt-coating
• Micro-encapsulation, coating by centrifugation, cryo-coating

Correct Answer: Film coating, sugar coating, enteric coating, compression coating

Q3. Which of the following polymers are commonly used as film-formers in aqueous film coating?

• Hydroxypropyl methylcellulose (HPMC), ethylcellulose, Eudragit (acrylic polymers)
• Polyvinyl alcohol (as sole film former for enteric protection)
• Gelatin only
• Polyethylene glycol (as primary film former)

Correct Answer: Hydroxypropyl methylcellulose (HPMC), ethylcellulose, Eudragit (acrylic polymers)

Q4. What is the principal role of a plasticizer in a film coating formulation?

• To increase the opacity of the film
• To reduce the melting point of the core tablet
• To increase film flexibility and prevent brittleness and cracking
• To act as the primary solvent in aqueous coatings

Correct Answer: To increase film flexibility and prevent brittleness and cracking

Q5. Which coating equipment is characterized by good drying efficiency, solvent recovery and high production throughput for tablet film coating?

• Handheld spray coater
• Classical non-perforated coating pan
• Perforated coating pan (e.g., perforated pan coater or Hi-Coater)
• Rotary drum without airflow control

Correct Answer: Perforated coating pan (e.g., perforated pan coater or Hi-Coater)

Q6. Which process parameter most directly determines the average droplet size produced from a spray nozzle during coating?

• Pan diameter
• Atomization air pressure (or spray pressure)
• Tablet friability
• Coating colorant concentration

Correct Answer: Atomization air pressure (or spray pressure)

Q7. In coating terminology, what does “weight gain” refer to?

• The increase in coating pan weight over a batch
• The percentage increase in tablet weight due to the applied coating
• The weight of solvent evaporated during coating
• The weight of coating equipment accessories

Correct Answer: The percentage increase in tablet weight due to the applied coating

Q8. Compared with aqueous coating systems, what is the main safety concern associated with organic solvent-based coatings?

• They always produce harder films than aqueous systems
• Higher risk of flammability and explosion requiring explosion-proof equipment
• They cannot be used for enteric coatings
• They are always more cost-effective and therefore preferred

Correct Answer: Higher risk of flammability and explosion requiring explosion-proof equipment

Q9. Mottling (uneven color distribution) on film-coated tablets is most commonly caused by which factor?

• Uniform atomization and low solids in spray solution
• Incorrect tablet core size only
• Migration of pigment or dye and surface energy differences between coated regions
• Excessive curing at high temperature

Correct Answer: Migration of pigment or dye and surface energy differences between coated regions

Q10. The principal purpose of enteric coating on tablets is to:

• Ensure immediate release of drug in the stomach
• Prevent drug release in the stomach and allow release in the small intestine
• Make the tablet taste better
• Increase tablet friability intentionally

Correct Answer: Prevent drug release in the stomach and allow release in the small intestine

Q11. Which of the following is a commonly used plasticizer in pharmaceutical film coatings?

• Triethyl citrate
• Sodium chloride
• Magnesium stearate (used as sole plasticizer)
• Microcrystalline cellulose

Correct Answer: Triethyl citrate

Q12. Why is a curing (or annealing) step applied after film coating?

• To dissolve the tablet core
• To evaporate residual solvent and promote film coalescence, improving mechanical properties
• To remove the coating entirely and recoat
• To neutralize the pH of the coating

Correct Answer: To evaporate residual solvent and promote film coalescence, improving mechanical properties

Q13. The “orange peel” surface defect in film-coated tablets is generally caused by:

• Excessive tablet hardness only
• Too low coating solution solids content and very fine droplets
• Excessive spray solids, high solution viscosity, and inadequate atomization resulting in surface roughness
• Correct curing time and proper atomization

Correct Answer: Excessive spray solids, high solution viscosity, and inadequate atomization resulting in surface roughness

Q14. Compression coating is particularly useful in tablet manufacturing when:

• You need to apply a very thin polymeric film only
• Two incompatible APIs must be physically separated or a layered modified-release profile is required
• Core tablets are too large to handle
• Only sugar coatings are intended

Correct Answer: Two incompatible APIs must be physically separated or a layered modified-release profile is required

Q15. Which analytical approach is most commonly used to assess coating uniformity on a tablet batch?

• Measuring tablet disintegration time only
• Determination of weight gain of individual tablets and measurement of coating thickness
• Assaying color intensity with a pH meter
• Measuring bulk density of uncoated granules

Correct Answer: Determination of weight gain of individual tablets and measurement of coating thickness

Q16. Increasing the solids content of a coating suspension will typically have which immediate effects?

• Decrease viscosity and increase drying time
• Reduce viscosity and prevent spray nozzle blockage
• Increase viscosity, reduce drying time per unit coating mass but raise risk of spray blockage and rough film
• Make the coating fully water-soluble regardless of polymer

Correct Answer: Increase viscosity, reduce drying time per unit coating mass but raise risk of spray blockage and rough film

Q17. Which polymer listed below is water-insoluble and frequently used as a moisture barrier or for sustained/modified release coatings?

• Hydroxypropyl methylcellulose (HPMC)
• Ethylcellulose
• Sodium starch glycolate
• Sodium chloride

Correct Answer: Ethylcellulose

Q18. Which parameter is least critical when considering scale-up of a tablet coating process from lab to production?

• Spray droplet size and spray pattern
• Residence time (batch time) and drying capacity
• Coating pan geometry and airflow distribution
• Color of the uncoated tablet core

Correct Answer: Color of the uncoated tablet core

Q19. One major advantage of fluidized bed coating compared with traditional pan coating is:

• It cannot coat pellets or granules
• Better heat and mass transfer leading to faster drying and more uniform coatings on particles
• Elimination of the need for atomization
• It requires no airflow and hence is dryer-independent

Correct Answer: Better heat and mass transfer leading to faster drying and more uniform coatings on particles

Q20. Tablet sticking during coating is most commonly attributed to which of the following?

• Excessive tablet colorant only
• Presence of tacky components on the tablet surface combined with inadequate drying and low inlet air temperature
• High pan speed always preventing contact between tablets
• Using too much talc as an anti-tacking agent

Correct Answer: Presence of tacky components on the tablet surface combined with inadequate drying and low inlet air temperature

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