Introduction to soft gelatin capsules MCQs With Answer

Introduction: Soft gelatin capsules (softgels) are a key dosage form studied in B. Pharm courses, combining a gelatin shell, plasticizer and liquid or semi-solid fill to improve drug stability and bioavailability. This introduction covers formulation principles, gelatin types, plasticizers, encapsulation methods, filling techniques, manufacturing equipment, quality control tests, stability issues like crosslinking and moisture migration, and regulatory considerations. Understanding shell composition, fill compatibility, and testing (disintegration, dissolution, leak and uniformity) is essential for formulation and industrial production. Practical knowledge of softgel design, packaging, and troubleshooting supports safe, effective product development. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the primary role of the plasticizer in a soft gelatin capsule shell?

• Increase shell permeability to water
• Make the shell more flexible and reduce brittleness
• Act as a preservative for the fill content
• Enhance the drug’s solubility in the fill

Correct Answer: Make the shell more flexible and reduce brittleness

Q2. Which material is most commonly used as the base polymer for softgel shells?

• Hydroxypropyl methylcellulose (HPMC)
• Gelatin
• Polyvinyl alcohol (PVA)
• Ethyl cellulose

Correct Answer: Gelatin

Q3. Which plasticizer is frequently used in soft gelatin capsule shells?

• Glycerin
• Sodium lauryl sulfate
• Propylene glycol alginate
• Stearic acid

Correct Answer: Glycerin

Q4. What is “bloom strength” in relation to gelatin?

• A measure of gelatin viscosity at 40°C
• The pH at which gelatin dissolves
• A measure of gelatin gel firmness and gel strength
• The melting point of gelatin in °C

Correct Answer: A measure of gelatin gel firmness and gel strength

Q5. Which encapsulation method is commonly used for commercial softgel production?

• Rotary die encapsulation
• Molding by solvent casting
• Direct compression into shells
• Syringe filling into two-piece capsules

Correct Answer: Rotary die encapsulation

Q6. Which type of fill is most suitable for soft gelatin capsules?

• Highly aqueous solutions (>90% water)
• Volatile gaseous fills
• Oils, oily solutions and non-aqueous suspensions
• Dry powders

Correct Answer: Oils, oily solutions and non-aqueous suspensions

Q7. What is the common cause of gelatin shell crosslinking?

• High humidity only
• Reaction with aldehydes or reactive excipients leading to increased gel rigidity
• Excessive plasticizer in shell
• Low-temperature storage

Correct Answer: Reaction with aldehydes or reactive excipients leading to increased gel rigidity

Q8. Which test is essential to detect leaks or perforations in softgels?

• Disintegration test
• Dye penetration or vacuum tumbling leak test
• Friability test
• Melting point determination

Correct Answer: Dye penetration or vacuum tumbling leak test

Q9. Why is moisture content critical for soft gelatin capsules?

• It affects shell flexibility, stability and can promote microbial growth if extreme
• It changes drug potency directly
• It is irrelevant if plasticizer is present
• It only affects the color of the shell

Correct Answer: It affects shell flexibility, stability and can promote microbial growth if extreme

Q10. Which property of the fill can cause migration of plasticizer from shell to fill?

• Hydrophobicity of the shell
• High affinity of fill components (e.g., certain solvents) for plasticizer
• Low melting point of the drug
• High viscosity of the shell solution

Correct Answer: High affinity of fill components (e.g., certain solvents) for plasticizer

Q11. The isoelectric point (pI) of gelatin influences:

• Only the color of the shell
• Interactions with charged drugs and stability of the shell in various pH environments
• The encapsulation speed on the machine
• The melting temperature of the fill

Correct Answer: Interactions with charged drugs and stability of the shell in various pH environments

Q12. Which additive is often included in softgel shell formulations to control microbial growth?

• Antioxidants such as BHT
• Preservatives like parabens or sorbic acid
• Surfactants such as polysorbate 80
• Flavoring agents

Correct Answer: Preservatives like parabens or sorbic acid

Q13. Which quality test assesses the rate and extent of drug release from softgels?

• Leak test
• Dissolution testing
• Uniformity of weight
• Moisture sorption analysis

Correct Answer: Dissolution testing

Q14. Compared with hard gelatin capsules, a key advantage of softgels is:

• Better suitability for dry powder fills
• Improved dosing flexibility for complex multi-unit doses
• Enhanced stability and bioavailability for lipophilic drugs
• Lower manufacturing capital cost

Correct Answer: Enhanced stability and bioavailability for lipophilic drugs

Q15. Which environmental condition is most likely to cause softgel shells to become sticky and deform?

• Low temperature (0–5°C)
• High relative humidity and elevated temperature
• Complete dryness (<5% RH)
• High vacuum storage

Correct Answer: High relative humidity and elevated temperature

Q16. What is the role of titanium dioxide in softgel shell formulations?

• Primary plasticizer
• Opacifier and colorant to provide opacity and whiteness
• Solvent for the fill material
• pH stabilizer of the gelatin solution

Correct Answer: Opacifier and colorant to provide opacity and whiteness

Q17. In rotary die encapsulation, the two gelatin ribbons are joined and filled at:

• The tablet press station
• The die rolls where cavities form and are sealed
• The coating pan
• The drying tunnel exit

Correct Answer: The die rolls where cavities form and are sealed

Q18. Which test is used to verify content uniformity in soft gelatin capsules?

• Uniformity of weight alone
• Individual content assay of drug substance per unit
• Only visual inspection
• Disintegration time only

Correct Answer: Individual content assay of drug substance per unit

Q19. A major incompatibility concern when formulating softgels is:

• Use of non-volatile oils
• Reactive fill components (e.g., aldehydes) that crosslink gelatin
• Low drug potency compounds
• High molecular weight polymers in the shell

Correct Answer: Reactive fill components (e.g., aldehydes) that crosslink gelatin

Q20. Why are antioxidants often added to softgel fills?

• To increase shell flexibility
• To protect oxidative-labile actives or oils from rancidity
• To adjust fill viscosity
• To act as a preservative for gelatin

Correct Answer: To protect oxidative-labile actives or oils from rancidity

Q21. Which analytical method is commonly used to determine residual moisture in softgels?

• Karl Fischer titration
• UV spectrophotometry
• Atomic absorption spectroscopy
• Melting point analysis

Correct Answer: Karl Fischer titration

Q22. The term “seam” in a softgel refers to:

• The internal fill compartment divider
• The weld line where two gelatin ribbons are sealed together
• A decorative marking on the shell
• The site of color pigment application

Correct Answer: The weld line where two gelatin ribbons are sealed together

Q23. Which coating approach is most appropriate when an enteric release is required for softgels?

• Direct enteric coating of intact softgels with suitable polymers
• Mixing enteric polymer into the gelatin shell
• Increasing shell moisture
• Reducing fill viscosity

Correct Answer: Direct enteric coating of intact softgels with suitable polymers

Q24. What is the main reason to use HPMC or plant-based shells instead of gelatin?

• Lower production cost compared to gelatin
• Vegan/vegetarian or halal requirements and thermally stable alternatives
• HPMC provides greater flexibility than gelatin
• HPMC increases water content of the fill

Correct Answer: Vegan/vegetarian or halal requirements and thermally stable alternatives

Q25. During stability studies, a decrease in shell plasticizer content would most likely cause:

• Increased shell flexibility
• Increased brittleness and potential shell cracking
• Improved dissolution rate
• Lower drug potency due to plasticizer loss

Correct Answer: Increased brittleness and potential shell cracking

Q26. Which parameter is measured by the disintegration test for softgels?

• Integrity and time for the shell to rupture under specified conditions
• Total moisture content
• Amount of plasticizer migrated
• Color uniformity of the shell

Correct Answer: Integrity and time for the shell to rupture under specified conditions

Q27. Which of the following is a typical way to minimize loss of volatile fill components during encapsulation?

• Operate the encapsulation at higher temperatures
• Formulate with higher vapor pressure solvents
• Use vacuum drying immediately after encapsulation
• Optimize fill temperature and use equipment to minimize exposure and volatilization

Correct Answer: Optimize fill temperature and use equipment to minimize exposure and volatilization

Q28. What does “plasticizer migration” refer to in softgel technology?

• Diffusion of plasticizer from shell to fill or packaging, altering shell properties
• Movement of the filled drug within the shell
• Migration of gelatin molecules across the seam
• Transport of moisture from fill to external environment

Correct Answer: Diffusion of plasticizer from shell to fill or packaging, altering shell properties

Q29. Which in-process control is important to ensure accurate fill weight in softgel manufacturing?

• Pill imprinting check
• Monitoring fill pump speed and viscosity of fill formulation
• Final packaging tightness
• Color consistency of the shell

Correct Answer: Monitoring fill pump speed and viscosity of fill formulation

Q30. Which regulatory aspect is critical for commercial softgel products?

• Detailed justification of flavoring agents only
• Documentation of formulation, manufacturing parameters, stability data and quality control specifications
• Use of only natural colorants
• Complete absence of plasticizers in the shell

Correct Answer: Documentation of formulation, manufacturing parameters, stability data and quality control specifications

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