Coating materials MCQs With Answer provide B.Pharm students an essential review of film and functional coatings used in solid dosage forms. This concise, keyword-rich introduction covers coating polymers, plasticizers, solvents, pigments, enteric coatings, aqueous vs. organic systems, and film formation mechanisms. Emphasis is on practical aspects: coating equipment, process parameters, common defects, quality control tests, dissolution behavior, and stability. These focused MCQs reinforce understanding of polymer chemistry, pH-dependent release, plasticizer selection, and evaluation techniques used in pharmaceutical development and manufacturing. Ideal for exam prep and practical labs, the set deepens knowledge on formulation choices and troubleshooting. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What is the primary function of a plasticizer in polymeric film coatings?
- Increase the molecular weight of the polymer
- Reduce the glass transition temperature and increase flexibility
- Act as a pigment to mask tablet color
- Accelerate solvent evaporation during spraying
Correct Answer: Reduce the glass transition temperature and increase flexibility
Q2. Which polymer is commonly used for enteric coatings to prevent drug release in the stomach?
- Hydroxypropyl methylcellulose (HPMC)
- Cellulose acetate phthalate (CAP)
- Polyethylene glycol (PEG)
- Polyvinyl alcohol (PVA)
Correct Answer: Cellulose acetate phthalate (CAP)
Q3. Which coating technique is most suitable for heat-sensitive drugs to avoid high temperature exposure?
- Sugar coating in a conventional pan
- High-temperature oven curing
- Fluid bed coating with low inlet air temperature
- Hot-melt coating
Correct Answer: Fluid bed coating with low inlet air temperature
Q4. Film coatings primarily control which of the following attributes of oral solid dosage forms?
- Tablet core hardness only
- Dissolution, taste masking, and physical protection
- API chemical stability only
- Particle size distribution of the drug
Correct Answer: Dissolution, taste masking, and physical protection
Q5. Which term describes the percentage increase in tablet weight due to coating?
- Bulk density
- Coating efficiency
- Weight gain (percent weight gain)
- Loss on drying
Correct Answer: Weight gain (percent weight gain)
Q6. Which solvent system is preferred for environmentally safe and industrial aqueous film coating?
- Chlorinated organic solvents
- Alcoholic solvents only
- Water-based dispersions or solutions
- Ketone-based solvents
Correct Answer: Water-based dispersions or solutions
Q7. Which coating defect is characterized by small, crater-like holes on the film surface caused by trapped air or volatile components?
- Orange peel
- Pitting
- Twinning
- Peeling
Correct Answer: Pitting
Q8. Eudragit L100 and S100 are examples of polymers used for which purpose?
- Immediate release hydrophilic coatings
- Enteric or pH-dependent release coatings
- Plasticizers for improving flexibility
- Color pigments in sugar coatings
Correct Answer: Enteric or pH-dependent release coatings
Q9. Which parameter directly affects droplet size during spray coating in a fluid bed or pan coater?
- Tablet tensile strength
- Atomization air pressure and nozzle design
- Active pharmaceutical ingredient potency
- Coating weight gain only
Correct Answer: Atomization air pressure and nozzle design
Q10. What is the role of talc in aqueous film coating formulations?
- Plasticizer to reduce Tg
- Anti-tacking agent and opacity enhancer
- Primary film former
- Solvent for polymer dissolution
Correct Answer: Anti-tacking agent and opacity enhancer
Q11. Which analytical test is commonly used to assess coating performance related to drug release?
- Fourier-transform infrared spectroscopy (FTIR) for solvent residues
- Dissolution testing in simulated gastric and intestinal fluids
- Viscometry of the core tablet
- Melting point determination
Correct Answer: Dissolution testing in simulated gastric and intestinal fluids
Q12. Which factor most influences the film formation of aqueous polymer dispersions?
- Particle size of the uncoated core
- Polymer minimum film-forming temperature (MFT)
- Tablet friability prior to coating
- Amount of API in the core
Correct Answer: Polymer minimum film-forming temperature (MFT)
Q13. Which coating type is typically used for taste masking of bitter APIs without modifying release?
- Enteric coating
- Sugar coating or thin film coating for taste masking
- Immediate-release high-porosity coating
- Controlled-release matrix coating
Correct Answer: Sugar coating or thin film coating for taste masking
Q14. Which excipient class improves adhesion between the coating and tablet core?
- Antioxidants
- Tackifiers and binders (e.g., HPMC, PVA)
- Opacifiers only
- Desiccants
Correct Answer: Tackifiers and binders (e.g., HPMC, PVA)
Q15. What is the primary cause of “blistering” or lifting of the coating from the tablet surface?
- Excessive use of pigments
- Rapid solvent evaporation leading to internal vapor pressure
- Insufficient API load
- High tablet hardness
Correct Answer: Rapid solvent evaporation leading to internal vapor pressure
Q16. Which polymer is commonly used as a pore former in sustained-release coatings to modulate water uptake?
- Polyethylene glycol (PEG)
- Magnesium stearate
- Talc
- Microcrystalline cellulose
Correct Answer: Polyethylene glycol (PEG)
Q17. During coating, what does a high spray rate relative to drying capacity typically cause?
- Improved film uniformity
- Over-wetting, agglomeration, and sticking
- Reduced process time without defects
- Lower residual solvent levels
Correct Answer: Over-wetting, agglomeration, and sticking
Q18. Which property of a coating polymer most directly impacts its ability to prevent acid penetration?
- Color
- Hydrophobicity and cross-linking density
- Plasticizer content only
- Viscosity of the coating suspension
Correct Answer: Hydrophobicity and cross-linking density
Q19. What is the purpose of curing (annealing) coated tablets after film application?
- To increase tablet weight by solvent absorption
- To allow polymer chains to rearrange, improving film integrity and reducing residual solvent
- To remove pigments from the surface
- To decrease tablet hardness
Correct Answer: To allow polymer chains to rearrange, improving film integrity and reducing residual solvent
Q20. Which coating evaluation technique measures coating thickness non-destructively?
- Mercury intrusion porosimetry
- Optical microscopy after cross-sectioning only
- X-ray microtomography or coating gauge techniques
- Karl Fischer titration
Correct Answer: X-ray microtomography or coating gauge techniques
Q21. Which of the following is a disadvantage of sugar coating compared to film coating?
- Faster manufacturing time
- Higher tablet weight gain and longer processing time
- Better gloss and elegance
- Lower use of solvents
Correct Answer: Higher tablet weight gain and longer processing time
Q22. Which coating defect appears as a wrinkled or crinkled surface resembling an orange peel?
- Pitting
- Orange peel
- Bridging or filling in of tablet embossing
- Peeling
Correct Answer: Orange peel
Q23. For pH-dependent release, at what pH should an enteric coating generally remain intact?
- At pH greater than the polymer’s dissolution threshold
- At pH below the polymer’s dissolution threshold (acidic gastric pH)
- At neutral and basic pH only
- At any pH; enteric coatings dissolve immediately
Correct Answer: At pH below the polymer’s dissolution threshold (acidic gastric pH)
Q24. Which plasticizer is frequently used with aqueous acrylic dispersions to improve film flexibility?
- Triethyl citrate
- Calcium carbonate
- Sodium chloride
- Magnesium stearate
Correct Answer: Triethyl citrate
Q25. Which measurement helps predict the risk of coating cracking during storage?
- Moisture sorption isotherms and Tg relative to storage temperature
- Tablet disintegration time
- API melting point only
- Bulk powder flow properties
Correct Answer: Moisture sorption isotherms and Tg relative to storage temperature
Q26. Which coating approach is best for creating sustained-release tablets by controlling drug diffusion through a polymer film?
- Immediate-release sugar coating
- Non-erodible water-insoluble polymer film with controlled porosity
- Enteric coating that dissolves in the intestine
- Simple aqueous HPMC coating with no modifiers
Correct Answer: Non-erodible water-insoluble polymer film with controlled porosity
Q27. What is a common method to quantify residual organic solvent in coated tablets?
- High-performance liquid chromatography (HPLC)
- Gas chromatography (GC) with headspace sampling
- UV-visible spectroscopy of the core tablet
- Thermogravimetric analysis for moisture only
Correct Answer: Gas chromatography (GC) with headspace sampling
Q28. Which excipient class imparts opacity and whiteness to a film coating?
- Plasticizers
- Opacifiers/pigments such as titanium dioxide
- Solvents
- Preservatives
Correct Answer: Opacifiers/pigments such as titanium dioxide
Q29. In comparing pan coating and fluid bed coating, which statement is true?
- Pan coating provides better control for small particles than fluid bed coating
- Fluid bed coating generally offers faster drying and is better for granules and pellets
- Pan coating cannot be used for film coatings
- Fluid bed coating is only suitable for sugar coating
Correct Answer: Fluid bed coating generally offers faster drying and is better for granules and pellets
Q30. Which process variable is adjusted to reduce tablet sticking during aqueous film coating?
- Lowering inlet air temperature drastically below MFT
- Using appropriate anti-tacking agents and optimized drying and spray parameters
- Increasing tablet core porosity only
- Removing plasticizer from the formulation entirely
Correct Answer: Using appropriate anti-tacking agents and optimized drying and spray parameters
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