Excipients used in semisolid dosage forms MCQs With Answer

Excipients used in semisolid dosage forms MCQs With Answer — This concise introduction reviews essential excipients commonly used in semisolid formulations such as ointments, creams, gels and pastes. Topics include gelling agents (Carbopol, cellulose derivatives), emulsifiers (Tween, Span, glyceryl esters), humectants, preservatives, antioxidants, penetration enhancers, thickeners, levigating and occlusive agents, and selection criteria for stability, compatibility and patient acceptability. Emphasis is on functions, examples, formulation challenges, rheology, and quality control relevant to B.Pharm students preparing for exams. Clear understanding of excipient roles helps optimize drug release, stability and safety in topical therapy. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the primary role of excipients in semisolid dosage forms?

• Only to act as inert fillers without affecting performance
• Modify consistency, stability, drug release and patient acceptability
• Replace the active pharmaceutical ingredient
• Prevent packaging interactions exclusively

Correct Answer: Modify consistency, stability, drug release and patient acceptability

Q2. Which of the following is a commonly used synthetic gelling agent for topical gels?

• Lanolin
• Carbopol (Carbomer)
• White soft paraffin
• Beeswax

Correct Answer: Carbopol (Carbomer)

Q3. Which excipient is suitable as a water-in-oil (W/O) emulsifier?

• Tween 80 (Polysorbate 80)
• Span 80 (Sorbitan monooleate)
• Polyethylene glycol 400
• Glycerin

Correct Answer: Span 80 (Sorbitan monooleate)

Q4. What is the purpose of levigating agents in semisolid preparations?

• To neutralize acidic drugs
• To wet and reduce particle size of insoluble powders
• To act as preservatives
• To increase occlusiveness

Correct Answer: To wet and reduce particle size of insoluble powders

Q5. An occlusive excipient in an ointment mainly functions to:

• Promote evaporation of water from the skin
• Decrease transepidermal water loss and increase hydration
• Act as a preservative
• Enhance drug solubility in water

Correct Answer: Decrease transepidermal water loss and increase hydration

Q6. Which preservative is most commonly used in semisolid topical formulations?

• Methylparaben
• EDTA
• Vitamin E (tocopherol)
• Citric acid

Correct Answer: Methylparaben

Q7. Which excipient acts as a humectant to retain moisture in semisolid gels?

• Mineral oil
• Glycerin
• White wax
• Stearic acid

Correct Answer: Glycerin

Q8. Why is compatibility testing between drug and excipients important in semisolids?

• To improve packaging aesthetics only
• To detect physical or chemical interactions affecting stability and efficacy
• To choose a colorant for the product
• To reduce manufacturing time exclusively

Correct Answer: To detect physical or chemical interactions affecting stability and efficacy

Q9. Which class of excipients most improves spreadability of a topical semisolid?

• Antioxidants
• Emollients and surfactants
• Chelating agents
• Buffers

Correct Answer: Emollients and surfactants

Q10. Which of the following is a commonly used penetration enhancer in topical semisolids?

• Propylene glycol
• Sodium chloride
• White petrolatum
• Beeswax

Correct Answer: Propylene glycol

Q11. Which polymer requires neutralization with a base to produce a gel?

• Hydroxypropyl methylcellulose (HPMC)
• Carbopol (Carbomer)
• Xanthan gum
• Beeswax

Correct Answer: Carbopol (Carbomer)

Q12. A common physical instability observed in semisolid emulsions is:

• Polymerization
• Phase separation (creaming or breaking)
• Color inversion
• Increased pH to 14

Correct Answer: Phase separation (creaming or breaking)

Q13. Which excipient is typically added to control pH in topical formulations?

• Phosphate buffer
• Lanolin
• Mineral oil
• White soft paraffin

Correct Answer: Phosphate buffer

Q14. Which semisolid base is considered water-washable and non-greasy?

• Hydrocarbon base (white petrolatum)
• O/W emulsion (cream)
• Anhydrous silicone base
• Lanolin

Correct Answer: O/W emulsion (cream)

Q15. Emulsifiers with a high HLB value (>10) are generally suitable for:

• W/O emulsions
• O/W emulsions
• Solid dispersions
• Non-aqueous ointments only

Correct Answer: O/W emulsions

Q16. The role of antioxidants in semisolid formulations is to:

• Preserve against microbial contamination
• Prevent oxidative degradation of drugs and lipids
• Enhance skin penetration
• Act as levigating agents

Correct Answer: Prevent oxidative degradation of drugs and lipids

Q17. Which natural wax is commonly used as a structuring agent in ointments?

• Polyethylene glycol 400
• Beeswax
• Propylene glycol
• Sorbitan monooleate

Correct Answer: Beeswax

Q18. Which fatty acid is often used as a penetration enhancer in topical formulations?

• Oleic acid
• Stearic acid only for occlusion
• Glyceryl monostearate exclusively
• Lanolin alcohols

Correct Answer: Oleic acid

Q19. For minimizing oxidation and microbial entry, packaging for semisolids should be:

• Transparent with large headspace
• Collapsible or air-tight with minimal headspace
• Porous jars to allow aeration
• Open-top containers

Correct Answer: Collapsible or air-tight with minimal headspace

Q20. Which rheological parameter primarily describes resistance to flow in semisolid bases?

• Spreadability index
• Viscosity
• pH
• Cloud point

Correct Answer: Viscosity

Q21. Which levigating agent is suitable for incorporation of insoluble powder into an oil-based ointment?

• Glycerin
• Mineral oil
• Water
• Phosphate buffer

Correct Answer: Mineral oil

Q22. Which preservative is most effective in acidic semisolid formulations (low pH)?

• Sodium benzoate
• Benzalkonium chloride (high pH dependent)
• EDTA alone
• White petrolatum

Correct Answer: Sodium benzoate

Q23. The main purpose of adding a chelating agent like EDTA to semisolid products is to:

• Increase viscosity
• Bind metal ions to prevent degradation and enhance preservative efficacy
• Act as a primary preservative
• Serve as a gelling agent

Correct Answer: Bind metal ions to prevent degradation and enhance preservative efficacy

Q24. Which excipient can act both as an emulsifier and a thickening/stabilizing agent in creams?

• Cetostearyl alcohol
• White wax
• Paraffin oil
• Sodium chloride

Correct Answer: Cetostearyl alcohol

Q25. Which semisolid base is highly occlusive and non-water washable?

• Hydrophilic ointment (PEG base)
• White soft paraffin (petrolatum)
• O/W cream
• Aqueous gel

Correct Answer: White soft paraffin (petrolatum)

Q26. Which sterilization method is suitable for heat-sensitive semisolid products where terminal sterilization is not possible?

• Autoclaving at 121°C
• Gamma irradiation or aseptic processing
• Boiling
• Dry heat at 160°C

Correct Answer: Gamma irradiation or aseptic processing

Q27. Which class of excipients lowers surface tension and improves wetting and spreadability?

• Buffers
• Surfactants
• Chelating agents
• Antioxidants

Correct Answer: Surfactants

Q28. Which natural polysaccharide is commonly used as a thickener and stabilizer in topical gels?

• Carnauba wax
• Xanthan gum
• White soft paraffin
• Benzyl alcohol

Correct Answer: Xanthan gum

Q29. The penetrometer test in semisolids primarily measures:

• Microscopic particle size
• Consistency or firmness (penetration depth)
• Microbial content
• Evaporation rate

Correct Answer: Consistency or firmness (penetration depth)

Q30. Which microbiological test is routinely performed to assess microbial quality of non-sterile semisolid pharmaceuticals?

• Endotoxin test only
• Total aerobic microbial count (TAMC) and specified organism tests
• Viral load assay
• Sterility test for all non-sterile products

Correct Answer: Total aerobic microbial count (TAMC) and specified organism tests

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