Preparation of toothpastes MCQs With Answer

Introduction: Preparation of toothpastes MCQs With Answer is a focused quiz set designed for M.Pharm students studying Herbal Cosmetics (MPG 204T). This collection emphasizes formulation principles, excipient selection, manufacturing operations, compatibility issues and quality control tests specific to toothpastes, including herbal and therapeutic variants. Questions probe deeper concepts such as fluoride–abrasive interactions, rheology control, preservative strategies for plant extracts, and analytical tests like RDA and viscosity assessment. Use these MCQs to reinforce understanding of formulation decisions, scale-up challenges and regulatory considerations encountered when developing safe, stable and efficacious dentifrices.

Q1. Which abrasive is widely preferred in modern herbal and fluoride-compatible toothpaste formulations?

• Calcium carbonate
• Hydrated silica
• Aluminum oxide
• Sodium bicarbonate

Correct Answer: Hydrated silica

Q2. What is the primary role of a humectant in toothpaste formulation?

• Increase foam generation during brushing
• Prevent drying and maintain paste consistency
• Provide antimicrobial activity
• Enhance abrasivity for stain removal

Correct Answer: Prevent drying and maintain paste consistency

Q3. Which polymer is commonly used as a thickening and suspending agent to control toothpaste rheology?

• Sodium lauryl sulfate
• Carbomer (Carbopol)
• Sorbitol
• PEG 400

Correct Answer: Carbomer (Carbopol)

Q4. Which surfactant is most frequently used in conventional toothpastes to provide detergency and foam?

• Polysorbate 80
• Sodium lauryl sulfate
• Cetrimonium bromide
• Decyl glucoside

Correct Answer: Sodium lauryl sulfate

Q5. What does RDA stand for in the context of toothpaste evaluation?

• Relative Detergent Action
• Relative Dentin Abrasivity
• Rheological Dispersion Analysis
• Regional Dental Assessment

Correct Answer: Relative Dentin Abrasivity

Q6. Which abrasive–fluoride combination is known to reduce fluoride bioavailability by forming insoluble products?

• Hydrated silica with sodium fluoride
• Calcium carbonate with sodium fluoride
• Aluminum oxide with sodium monofluorophosphate
• Calcium carbonate with stannous fluoride

Correct Answer: Calcium carbonate with sodium fluoride

Q7. What is the main function of chelating agents such as EDTA in toothpaste?

• Act as primary humectants to retain moisture
• Sequester metal ions to prevent precipitation and staining
• Provide flavor enhancement for herbal extracts
• Increase abrasivity for calculus removal

Correct Answer: Sequester metal ions to prevent precipitation and staining

Q8. Which combination lists common humectants used in toothpaste formulations?

• Sorbitol and glycerin
• Carbomer and xanthan gum
• Sodium lauryl sulfate and polysorbate
• Calcium carbonate and hydrated silica

Correct Answer: Sorbitol and glycerin

Q9. What is the primary purpose of using a colloid mill or high-shear grinder during toothpaste manufacture?

• Increase pH to stabilize herbal actives
• Reduce particle size and produce a homogenous dispersion
• Add flavor oils uniformly without emulsifiers
• Sterilize the batch by heat generation

Correct Answer: Reduce particle size and produce a homogenous dispersion

Q10. Which pH range is generally targeted for over-the-counter adult toothpaste to balance stability and oral tolerance?

• 2.0–4.0
• 4.5–5.5
• 6.0–8.0
• 9.0–11.0

Correct Answer: 6.0–8.0

Q11. Which thickening agent is particularly known for imparting thixotropic (shear-thinning) behavior in toothpaste?

• Calcium carbonate
• Xanthan gum
• Sorbitol
• PEG 400

Correct Answer: Xanthan gum

Q12. Historically, which antibacterial agent was widely incorporated into toothpaste for plaque reduction (though its use has become controversial)?

• Triclosan
• Sodium chloride
• Benzoic acid
• Menthol

Correct Answer: Triclosan

Q13. Why is wet milling performed during toothpaste manufacturing rather than dry blending in most modern processes?

• To allow heat curing of thickeners
• To ensure uniform wet dispersion, reduce grit and control particle morphology
• To volatilize residual solvents from herbal extracts
• To increase the ionic strength of the paste

Correct Answer: To ensure uniform wet dispersion, reduce grit and control particle morphology

Q14. What is a major stability concern when incorporating herbal extracts into toothpaste formulations?

• Excessive foaming due to plant oils
• Microbial growth and chemical degradation of phytoconstituents
• Immediate neutralization of fluoride by herbs
• Spontaneous gelation at room temperature

Correct Answer: Microbial growth and chemical degradation of phytoconstituents

Q15. Typical concentration range for humectants (e.g., sorbitol, glycerin) in toothpaste formulations is approximately:

• 1–5% w/w
• 10–15% w/w
• 20–40% w/w
• 60–80% w/w

Correct Answer: 20–40% w/w

Q16. What is the principal function of sodium lauryl sulfate in many toothpaste formulations?

• Preserve herbal actives from oxidation
• Act as a humectant to prevent drying
• Provide foaming and detergent action to assist cleaning
• Stabilize fluoride ions against precipitation

Correct Answer: Provide foaming and detergent action to assist cleaning

Q17. Which type of packaging is preferred to limit moisture exchange and protect toothpaste from air and light during shelf life?

• Glass jar with screw cap
• Single-layer polyethylene tube
• Multi-layer laminated tube
• Cardboard sachet

Correct Answer: Multi-layer laminated tube

Q18. Which preservative is commonly used in toothpaste to prevent microbial contamination while being compatible with most excipients?

• Sodium benzoate
• Calcium chloride
• Hydrated silica
• Citric acid at 20% w/w

Correct Answer: Sodium benzoate

Q19. Compared with calcium carbonate abrasives, what is a key formulation advantage of hydrated silica?

• Higher reactivity with fluoride leading to more bioavailable fluoride
• Lower cost and easier sourcing
• Better compatibility with fluoride and controlled, less aggressive abrasivity
• Superior solubility in saliva for taste enhancement

Correct Answer: Better compatibility with fluoride and controlled, less aggressive abrasivity

Q20. Which manufacturing step is specifically used to remove entrapped air and reduce oxidation risk before filling toothpaste into tubes?

• Neutralization
• Deaeration
• Spray drying
• Lyophilization

Correct Answer: Deaeration

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