Antiperspirants and deodorants – actives and mechanism of action MCQs With Answer

Antiperspirants and deodorants are essential topical products studied in B.Pharm curricula, focusing on actives, formulation science, and mechanism of action. Antiperspirant actives — mainly aluminum salts such as aluminum chlorohydrate and aluminum zirconium complexes — reduce sweat by forming metal–protein complexes that occlude eccrine sweat ducts. Deodorants control body odor via antimicrobial agents, pH modifiers and fragrances that inhibit bacterial breakdown of apocrine sweat. Understanding vehicle selection (sticks, roll‑ons, aerosols), excipients, stability, skin irritation, analytical assays (ICP, titration, clinical efficacy tests) and regulatory status is vital for formulation and quality control. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which of the following best describes the primary mechanism of action of aluminum-based antiperspirant actives?

• Disruption of sweat gland innervation by neurotoxins
• Formation of metal–protein complexes that occlude sweat ducts
• Direct bactericidal action against odor-producing bacteria
• Neutralization of sweat pH to prevent sweating

Correct Answer: Formation of metal–protein complexes that occlude sweat ducts

Q2. Which compound is commonly used as an antiperspirant active in many commercial formulations?

• Triclosan
• Aluminum chlorohydrate
• Sodium lauryl sulfate
• Chlorhexidine gluconate

Correct Answer: Aluminum chlorohydrate

Q3. What is the primary functional difference between deodorants and antiperspirants?

• Deodorants reduce sweat volume; antiperspirants mask odor
• Antiperspirants reduce sweat secretion; deodorants control odor
• Deodorants act as systemic drugs; antiperspirants are cosmetics
• Antiperspirants increase skin pH; deodorants acidify skin

Correct Answer: Antiperspirants reduce sweat secretion; deodorants control odor

Q4. Which of the following aluminum complexes often includes zirconium and glycine in antiperspirant formulations?

• Aluminum chlorohydrate
• Aluminum zirconium tetrachlorohydrex glycine
• Aluminum sulfate
• Aluminum hydroxide gel

Correct Answer: Aluminum zirconium tetrachlorohydrex glycine

Q5. How do deodorant antimicrobial actives reduce body odor?

• By increasing sweat production so bacteria are diluted
• By inhibiting bacterial enzymes that generate volatile odorants
• By forming insoluble plugs in hair follicles
• By promoting growth of odor-producing bacteria

Correct Answer: By inhibiting bacterial enzymes that generate volatile odorants

Q6. Which vehicle type typically provides the longest lasting wetness control for antiperspirants?

• Water-based roll-on
• Aerosol spray
• Solid stick
• Powder

Correct Answer: Solid stick

Q7. Which analytical technique is commonly used to quantify total aluminum content in antiperspirant formulations?

• High-performance liquid chromatography (HPLC)
• Inductively coupled plasma optical emission spectroscopy (ICP-OES)
• Gas chromatography–mass spectrometry (GC-MS)
• UV-visible spectrophotometry without complexation

Correct Answer: Inductively coupled plasma optical emission spectroscopy (ICP-OES)

Q8. Which excipient class is most useful for thickening aqueous roll-on antiperspirant formulations?

• Waxes and petrolatum
• Carbomers and cellulose derivatives
• Volatile silicones
• Propellants

Correct Answer: Carbomers and cellulose derivatives

Q9. What is a major cause of fabric staining associated with antiperspirant use?

• Reaction of aluminum salts with sweat to form insoluble complexes
• Volatile fragrance oils dissolving textiles
• Propellant residues from aerosols
• Excess moisturizers leaving oil slicks

Correct Answer: Reaction of aluminum salts with sweat to form insoluble complexes

Q10. Which pH condition generally favors precipitation of aluminum-protein complexes in sweat ducts?

• Strongly alkaline pH (pH > 9)
• Neutral pH (around pH 7)
• Acidic to mildly acidic pH
• pH has no effect on precipitation

Correct Answer: Acidic to mildly acidic pH

Q11. Which preservative consideration is most important in aqueous deodorant formulations?

• Preservatives are unnecessary in aqueous systems
• Broad-spectrum antimicrobial preservation to prevent spoilage
• Only antifungal agents are required
• Use of oxidizing bleaches as preservatives

Correct Answer: Broad-spectrum antimicrobial preservation to prevent spoilage

Q12. In regulatory terms (e.g., US FDA), how are antiperspirants generally classified?

• As prescription drugs
• As over-the-counter (OTC) drugs under an antiperspirant monograph
• As medical devices
• As unregulated consumer products

Correct Answer: As over-the-counter (OTC) drugs under an antiperspirant monograph

Q13. Which of the following is a common sensory/performance test for antiperspirant efficacy in clinical studies?

• Patch test for sensitization only
• Gravimetric sweat measurement under standardized conditions
• pH profiling of skin surface only
• Fragrance intensity scoring in blind panels

Correct Answer: Gravimetric sweat measurement under standardized conditions

Q14. Which ingredient is typically used in deodorants for antimicrobial activity but faces regulatory restrictions in some regions?

• Glycerin
• Triclosan
• Stearyl alcohol
• Citric acid

Correct Answer: Triclosan

Q15. What is the principal reason antiperspirant plugs are considered reversible?

• The plugs are permanently fused to skin proteins
• They dissolve or are sloughed off with normal skin turnover and washing
• They migrate into deeper tissues and persist indefinitely
• They convert to soluble aluminum salts that enter the bloodstream

Correct Answer: They dissolve or are sloughed off with normal skin turnover and washing

Q16. Which propellant class is most commonly used in aerosol antiperspirants?

• Chlorofluorocarbons (CFCs)
• Hydrofluorocarbons exclusively
• Butane/isobutane/propane hydrocarbon blends
• Nitrogen only

Correct Answer: Butane/isobutane/propane hydrocarbon blends

Q17. Which in vitro test can be used to estimate antibacterial activity of deodorant actives?

• Pearson correlation assay
• Disk diffusion (zone of inhibition) assay
• Tensile strength test
• Viscosity profiling

Correct Answer: Disk diffusion (zone of inhibition) assay

Q18. Which skin reaction is most frequently associated with deodorant/antiperspirant use?

• Systemic anaphylaxis
• Contact dermatitis (irritant or allergic)
• Necrotizing fasciitis
• Photosensitivity leading to burns

Correct Answer: Contact dermatitis (irritant or allergic)

Q19. What formulation strategy can reduce skin irritation from aluminum salts?

• Increasing free acid content to very low pH
• Using buffered systems and lower active concentrations
• Avoiding any emollients or skin conditioners
• Adding strong surfactants to enhance penetration

Correct Answer: Using buffered systems and lower active concentrations

Q20. Which testing method directly assesses occlusion of sweat ducts by antiperspirant plugs in vivo?

• Skin biopsy and histological examination
• Colorimetric pH strip applied to skin
• Measurement of transepidermal water loss only
• Odor panel scoring alone

Correct Answer: Skin biopsy and histological examination

Q21. What role do volatile solvents (e.g., ethanol) play in roll‑on antiperspirant formulations?

• They fix aluminum salts permanently into skin tissues
• They act as carriers that evaporate, leaving actives deposited
• They serve as primary preservatives for long-term storage
• They convert aluminum salts to gaseous forms

Correct Answer: They act as carriers that evaporate, leaving actives deposited

Q22. Which microorganism group is primarily responsible for malodour formation in the axilla?

• Dermatophytes
• Anaerobic bacteria such as Corynebacterium and certain staphylococci
• Yeasts like Candida albicans
• Viruses resident on skin

Correct Answer: Anaerobic bacteria such as Corynebacterium and certain staphylococci

Q23. For quality control, which test assesses the sensory residue and feel of solid stick antiperspirants?

• Hardness or melt point testing and subjective application feel panels
• ICP-OES for aluminum
• EDTA titration for chloride content only
• Microbial limit test exclusively

Correct Answer: Hardness or melt point testing and subjective application feel panels

Q24. Which excipient is commonly used in stick antiperspirants to provide structural integrity?

• Low molecular weight alcohols
• Waxes such as beeswax or polyethylene wax
• High levels of water
• Strong acids

Correct Answer: Waxes such as beeswax or polyethylene wax

Q25. Which statement about aluminum systemic absorption from topical antiperspirants is most accurate based on current evidence?

• Topical antiperspirants result in high systemic aluminum accumulation comparable to parenteral intake
• Systemic absorption is minimal and not shown to cause systemic toxicity in general population
• Aluminum rapidly accumulates to toxic levels after a single application
• Aluminum from antiperspirants is entirely converted to elemental aluminum in body

Correct Answer: Systemic absorption is minimal and not shown to cause systemic toxicity in general population

Q26. Which analytical titration method can be used for aluminum quantification after appropriate sample preparation?

• Karl Fischer titration
• Complexometric titration with EDTA after masking interferences
• Turbidimetric sulfate titration
• Iodometric titration

Correct Answer: Complexometric titration with EDTA after masking interferences

Q27. What is the effect of sweating immediately after antiperspirant application on efficacy?

• Sweating enhances plug formation and increases efficacy
• Excess perspiration soon after application can wash away actives and reduce efficacy
• Sweating has no impact on antiperspirant performance
• Sweating converts actives into stronger toxins

Correct Answer: Excess perspiration soon after application can wash away actives and reduce efficacy

Q28. Which formulation parameter is important to control to prevent phase separation in cream antiperspirants?

• Percussion frequency during packaging only
• Emulsifier selection and hydrophilic–lipophilic balance (HLB)
• Avoiding any water in the formulation
• Using only volatile oils as the continuous phase

Correct Answer: Emulsifier selection and hydrophilic–lipophilic balance (HLB)

Q29. Which method is commonly used in clinical trials to evaluate deodorant efficacy against odor?

• Instrumental quantification of volatile organic compounds from skin samples
• Self-reported questionnaire only without objective measures
• Patch testing for irritation only
• Measurement of skin hydration by corneometry exclusively

Correct Answer: Instrumental quantification of volatile organic compounds from skin samples

Q30. Which precaution should formulators consider to minimize the risk of allergic contact dermatitis from deodorants?

• Maximize fragrance concentration to mask reactive chemicals
• Use hypoallergenic or fragrance-free formulations and test allergens like preservatives
• Avoid preservative systems altogether to eliminate sensitizers
• Increase alcohol content to denature all proteins on skin

Correct Answer: Use hypoallergenic or fragrance-free formulations and test allergens like preservatives

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