Introduction
Capsule excipients play vital roles in oral product development, influencing manufacturability, stability, release profile and bioavailability. For B. Pharm students, understanding common excipients — fillers/diluents (lactose, MCC), disintegrants (crospovidone, sodium starch glycolate), lubricants (magnesium stearate), glidants (colloidal silica), binders and plasticizers — is essential for formulation design and troubleshooting. Knowledge of capsule shell materials (gelatin, HPMC), moisture interactions, incompatibilities (e.g., Maillard reactions), and impact on dissolution and content uniformity is critical during development and quality control. You will also learn selection criteria, functional roles, and common pitfalls to optimize capsule performance. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which excipient is most commonly used as a diluent in hard capsule formulations?
- Magnesium stearate
- Microcrystalline cellulose (MCC)
- Colloidal silicon dioxide
- Crospovidone
Correct Answer: Microcrystalline cellulose (MCC)
Q2. What is the primary function of a lubricant in capsule filling?
- Enhance dissolution rate
- Improve flow by reducing cohesion
- Reduce friction between powder and die/punch
- Promote rapid disintegration
Correct Answer: Reduce friction between powder and die/punch
Q3. Which excipient is typically used as a glidant to improve powder flow?
- Sodium starch glycolate
- Colloidal silicon dioxide
- Polyvinylpyrrolidone (PVP)
- Lactose monohydrate
Correct Answer: Colloidal silicon dioxide
Q4. Which disintegrant acts primarily by swelling to break up the capsule fill?
- Magnesium stearate
- Croscarmellose sodium
- Polyethylene glycol
- Hydroxypropyl methylcellulose (HPMC)
Correct Answer: Croscarmellose sodium
Q5. In wet granulation for capsules, which excipient is commonly used as a binder?
- Colloidal silicon dioxide
- Polyvinylpyrrolidone (PVP)
- Magnesium carbonate
- Sodium lauryl sulfate
Correct Answer: Polyvinylpyrrolidone (PVP)
Q6. Which plasticizer is commonly added to gelatin capsule shells to impart flexibility?
- Sorbitol
- Calcium carbonate
- Avicel PH
- Colloidal silicon dioxide
Correct Answer: Sorbitol
Q7. What is a key difference between gelatin and HPMC (hypromellose) capsule shells?
- Gelatin is plant-derived while HPMC is animal-derived
- HPMC is less prone to enzymatic cross-linking than gelatin
- Gelatin has higher chemical resistance than HPMC
- HPMC cannot be used for vegetarian products
Correct Answer: HPMC is less prone to enzymatic cross-linking than gelatin
Q8. Gelatin cross-linking can adversely affect dissolution. Which agent is most associated with causing cross-linking?
- Polyethylene glycol
- Formaldehyde
- Colloidal silicon dioxide
- Magnesium stearate
Correct Answer: Formaldehyde
Q9. Which excipient is known to cause Maillard-type incompatibility with primary amine-containing drugs?
- Lactose
- Croscarmellose sodium
- Microcrystalline cellulose
- Magnesium stearate
Correct Answer: Lactose
Q10. Excessive magnesium stearate in a capsule fill commonly leads to which formulation problem?
- Improved wettability and faster dissolution
- Reduced powder flowability
- Hydrophobic surface causing slower dissolution
- Increased content uniformity
Correct Answer: Hydrophobic surface causing slower dissolution
Q11. Which method is most appropriate for quantifying trace water content in hygroscopic excipients used for capsules?
- High performance liquid chromatography (HPLC)
- Karl Fischer titration
- Loss on drying at 105 °C without specification
- Ultraviolet spectroscopy
Correct Answer: Karl Fischer titration
Q12. Which excipient selection consideration is most important to avoid segregation during capsule filling?
- Matching particle size and bulk density of components
- Using only hydrophobic excipients
- Adding excess lubricants to the blend
- Increasing capsule size irrespective of fill weight
Correct Answer: Matching particle size and bulk density of components
Q13. Which quality test specifically assesses uniformity of mass for single-dose capsule preparations?
- Disintegration test
- Content uniformity test
- Weight variation (uniformity of mass) test
- Dissolution test
Correct Answer: Weight variation (uniformity of mass) test
Q14. Which surfactant excipient is commonly added to capsule formulations to improve wetting and dissolution of poorly soluble drugs?
- Sodium lauryl sulfate (SLS)
- Magnesium stearate
- Lactose monohydrate
- Colloidal silicon dioxide
Correct Answer: Sodium lauryl sulfate (SLS)
Q15. For immediate-release hard gelatin capsules, which disintegration medium is commonly used in USP testing?
- Simulated intestinal fluid with enzymes only
- 0.1 N hydrochloric acid (simulated gastric fluid)
- Pure ethanol
- Phosphate buffer pH 7.4 only
Correct Answer: 0.1 N hydrochloric acid (simulated gastric fluid)
Q16. Which excipient is typically added to improve tablet/granule compressibility prior to capsule filling when using direct compression?
- Microcrystalline cellulose (MCC)
- Magnesium stearate
- Sodium lauryl sulfate
- Polysorbate 80
Correct Answer: Microcrystalline cellulose (MCC)
Q17. Which excipient is most suitable as a superdisintegrant for rapid capsule content breakup?
- Magnesium oxide
- Crospovidone
- Gelatin
- Polyethylene glycol 4000
Correct Answer: Crospovidone
Q18. Which parameter of a powder blend is directly improved by adding a small amount of colloidal silicon dioxide?
- Solubility of the active drug
- Bulk density to extremely high values
- Flowability by reducing interparticle cohesion
- Moisture uptake to zero
Correct Answer: Flowability by reducing interparticle cohesion
Q19. Which excipient is commonly used to mask unpleasant taste in formulations intended for opening capsules?
- Sodium chloride
- Sucralose or intense sweeteners
- Magnesium stearate
- Microcrystalline cellulose
Correct Answer: Sucralose or intense sweeteners
Q20. During preformulation, which analytical technique is most useful for detecting possible drug–excipient interactions via thermal events?
- Infrared spectroscopy (FTIR)
- Differential scanning calorimetry (DSC)
- Optical microscopy
- pH meter
Correct Answer: Differential scanning calorimetry (DSC)
Q21. Which excipient is often used as an anti-adherent to prevent sticking during capsule filling or tableting?
- Talc
- Polyvinylpyrrolidone (PVP)
- Croscarmellose sodium
- Gelatin
Correct Answer: Talc
Q22. For soft gelatin capsules, what distinguishes their excipient needs from hard capsules?
- Soft capsules use dry powders exclusively
- Soft capsules require plasticizers in the shell and typically contain liquid or semi-solid fills
- Hard capsules need no lubricants while soft capsules do
- Soft capsules never use surfactants
Correct Answer: Soft capsules require plasticizers in the shell and typically contain liquid or semi-solid fills
Q23. Which excipient can act both as a diluent and as a moisture scavenger to improve stability of moisture-sensitive APIs?
- Sorbitol
- Magnesium stearate
- Microcrystalline cellulose
- Silica gel or desiccant sachets exterior to packaging
Correct Answer: Silica gel or desiccant sachets exterior to packaging
Q24. Which choice best explains why particle size reduction of an API can improve capsule dissolution?
- Smaller particles reduce specific surface area
- Smaller particles increase wettability but decrease surface area
- Smaller particles increase surface area and reduce diffusion path length, enhancing dissolution
- Particle size has no effect on dissolution
Correct Answer: Smaller particles increase surface area and reduce diffusion path length, enhancing dissolution
Q25. Which excipient is most likely to decrease the rate of water penetration into a capsule fill, slowing disintegration?
- Sodium starch glycolate
- Hydrophobic lubricants like magnesium stearate
- Croscarmellose sodium
- Povidone (PVP)
Correct Answer: Hydrophobic lubricants like magnesium stearate
Q26. When designing a capsule formulation for a very low-dose potent drug, which excipient consideration is critical for content uniformity?
- Use of very coarse excipient particles only
- Ensuring intimate mixing and use of suitable carriers or granulation to prevent segregation
- Adding high levels of lubricant to the blend
- Excluding any glidants
Correct Answer: Ensuring intimate mixing and use of suitable carriers or granulation to prevent segregation
Q27. Which excipient is commonly used as a hygroscopic plasticizer in soft gelatin shell manufacture?
- Glycerol
- Microcrystalline cellulose
- Colloidal silicon dioxide
- Calcium phosphate
Correct Answer: Glycerol
Q28. Which excipient choice is best to enhance mechanical strength of granules to reduce friability prior to capsule filling?
- Superdisintegrants at high level
- Binders such as PVP or starch paste
- Excess glidant
- Sodium lauryl sulfate
Correct Answer: Binders such as PVP or starch paste
Q29. Which packaging/excipient interaction must be considered to prevent capsule shell brittleness during storage?
- Plasticizer migration or loss leading to shell brittleness
- Use of desiccants causing increased shell plasticity
- Adding too much lactose inside the capsule shell
- Using HPMC shells always leads to brittleness
Correct Answer: Plasticizer migration or loss leading to shell brittleness
Q30. Which excipient strategy can improve bioavailability of a poorly water-soluble drug in a capsule formulation?
- Use of hydrophobic lubricants alone
- Formulation as a solid dispersion with hydrophilic carriers or inclusion of surfactants
- Eliminating all disintegrants
- Increasing capsule shell thickness only
Correct Answer: Formulation as a solid dispersion with hydrophilic carriers or inclusion of surfactants
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