Introduction: Cosmetic excipients include a diverse group of ingredients—emollients, emulsifiers, surfactants, humectants, thickeners, preservatives, antioxidants, solubilizers and film formers—classified by function and chemical nature. Understanding classification, physico‑chemical properties, INCI names, excipient selection criteria, compatibility, stability issues and safety is essential for B.Pharm students designing topical formulations. Mastery of excipient applications—improving texture, stability, skin feel, penetration, preservation and sensory attributes—bridges theory and practical formulation. This concise, keyword‑rich overview emphasizes formulation roles, HLB concept, rheology modifiers, preservatives efficacy and interactions with active pharmaceutical ingredients. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which group best represents primary functional classifications of cosmetic excipients?
- Emollients, emulsifiers, humectants and preservatives
- Active pharmaceutical ingredients and solvents
- Only colorants and fragrances
- Packaging materials and labels
Correct Answer: Emollients, emulsifiers, humectants and preservatives
Q2. Which excipient type primarily reduces surface tension and stabilizes emulsions?
- Humectants
- Emulsifiers / surfactants
- Antioxidants
- Preservatives
Correct Answer: Emulsifiers / surfactants
Q3. The HLB (Hydrophilic–Lipophilic Balance) number is most useful for selecting which excipient?
- Preservatives
- Emulsifiers
- Antioxidants
- Fragrances
Correct Answer: Emulsifiers
Q4. Which of the following is a common humectant used to retain moisture in topical formulations?
- Carbomer
- Glycerin
- Titanium dioxide
- Paraffin
Correct Answer: Glycerin
Q5. Which excipient class is primarily used to increase viscosity and control rheology?
- Thickeners/rheology modifiers
- Emollients
- Fragrances
- Preservatives
Correct Answer: Thickeners/rheology modifiers
Q6. Which preservative is commonly used in cosmetics and known for broad‑spectrum antimicrobial activity?
- Phenoxyethanol
- Sodium lauryl sulfate
- Stearic acid
- Beeswax
Correct Answer: Phenoxyethanol
Q7. Which antioxidant is frequently added to oils and lipid phases to prevent rancidity?
- Tocopherol (Vitamin E)
- Carbomer 940
- Propylene glycol
- Sodium chloride
Correct Answer: Tocopherol (Vitamin E)
Q8. What is the primary functional role of emollients in a cream or lotion?
- Reduce microbial load
- Improve skin softness and barrier function
- Increase product foaming
- Act as primary active ingredient for acne
Correct Answer: Improve skin softness and barrier function
Q9. Which class of excipients helps solubilize lipophilic actives in aqueous cosmetic systems?
- Solubilizers (e.g., polysorbate 20, cyclodextrins)
- Thickeners (e.g., xanthan gum)
- Colorants
- Preservatives
Correct Answer: Solubilizers (e.g., polysorbate 20, cyclodextrins)
Q10. Carbomer is typically used in formulations as a:
- Preservative
- Rheology modifier / gelling agent
- Solubilizer for oils
- Emollient
Correct Answer: Rheology modifier / gelling agent
Q11. Which excipient class can act as both humectant and penetration enhancer?
- Propylene glycol
- Magnesium stearate
- Stearyl alcohol
- Color pigments
Correct Answer: Propylene glycol
Q12. INCI names are important because they:
- Provide standardized ingredient labeling for consumer safety and regulatory compliance
- Are only used for internal laboratory codes
- Determine packaging color
- Replace preservatives in formulations
Correct Answer: Provide standardized ingredient labeling for consumer safety and regulatory compliance
Q13. Which excipient commonly forms an occlusive layer to reduce transepidermal water loss?
- Petrolatum (vaseline)
- Sodium chloride
- Citric acid
- Glycerin
Correct Answer: Petrolatum (vaseline)
Q14. EDTA (ethylenediaminetetraacetic acid) is used in cosmetics primarily as a:
- Chelating agent to sequester metal ions
- Fragrance enhancer
- Primary solvent
- Sunscreen active
Correct Answer: Chelating agent to sequester metal ions
Q15. Which surfactant type is generally milder and preferred for sensitive skin formulations?
- Anionic surfactants like SLS
- Nonionic surfactants like polysorbates
- Cationic surfactants like benzalkonium chloride
- Strong amphoteric acids
Correct Answer: Nonionic surfactants like polysorbates
Q16. Which excipient class contributes to film formation for long‑lasting makeup or sunscreens?
- Film formers (e.g., acrylates copolymers)
- Humectants
- Antioxidants
- Thickeners
Correct Answer: Film formers (e.g., acrylates copolymers)
Q17. Which factor most strongly affects preservative efficacy in a formulation?
- Product pH
- Bottle color
- Label font size
- Fragrance concentration only
Correct Answer: Product pH
Q18. Which excipient is commonly used as a foam booster/stabilizer in shampoos?
- Lauryl sulfate (anionic surfactant)
- Glycerin
- Carbomer
- EDTA
Correct Answer: Lauryl sulfate (anionic surfactant)
Q19. Microemulsions differ from macroemulsions mainly by:
- Droplet size and thermodynamic stability
- Color only
- Being always oil‑free
- Having no surfactant
Correct Answer: Droplet size and thermodynamic stability
Q20. Which excipient would you select to increase spreadability and sensory silky feel in a cream?
- Dimethicone (silicone emollient)
- Sodium chloride
- Citric acid
- Calcium carbonate
Correct Answer: Dimethicone (silicone emollient)
Q21. Which preservative system is often compromised by high levels of chelators or strong surfactants?
- Paraben esters
- Alcohols like ethanol
- Heavy metal salts
- Inorganic pigments
Correct Answer: Paraben esters
Q22. Cyclodextrins are used in cosmetic formulations mainly to:
- Form inclusion complexes to solubilize volatile or poorly soluble actives
- Act as thickeners
- Provide color
- Serve as primary preservatives
Correct Answer: Form inclusion complexes to solubilize volatile or poorly soluble actives
Q23. Which rheology modifier is plant‑derived and often used in natural cosmetic claims?
- Xanthan gum
- Carbomer 934
- Polyvinylpyrrolidone
- Silica gel
Correct Answer: Xanthan gum
Q24. Which excipient interaction can cause emulsion destabilization such as creaming or coalescence?
- Incompatible surfactant and electrolyte addition
- Adding colorant at low concentration only
- Proper pH adjustment within recommended range
- Using appropriate HLB emulsifier
Correct Answer: Incompatible surfactant and electrolyte addition
Q25. Which excipient is typically avoided in eye products due to irritation potential?
- Sodium lauryl sulfate (SLS)
- Glycerin
- Hyaluronic acid
- Tocopherol
Correct Answer: Sodium lauryl sulfate (SLS)
Q26. A high HLB emulsifier (e.g., HLB >10) is most suitable for forming which type of emulsion?
- Water-in-oil (W/O)
- Oil-in-water (O/W)
- Anhydrous gels
- Solid sticks
Correct Answer: Oil-in-water (O/W)
Q27. Which excipient can act as both preservative booster and humectant and is often used at low concentrations?
- Propylene glycol
- Stearic acid
- Beeswax
- Titanium dioxide
Correct Answer: Propylene glycol
Q28. Which test is commonly used to evaluate physical stability of emulsions during formulation development?
- Centrifugation and accelerated temperature cycling
- pH labeling verification only
- Fragrance sniff test
- Packaging drop test only
Correct Answer: Centrifugation and accelerated temperature cycling
Q29. Which excipient class is critical for sunscreen formulations to maintain dispersion and photostability of UV filters?
- Solubilizers, film formers and emulsifiers
- Food preservatives only
- Color lakes exclusively
- Metal salts as opacifiers
Correct Answer: Solubilizers, film formers and emulsifiers
Q30. Which formulation consideration is most important when combining a cationic polymer and an anionic surfactant?
- Risk of incompatibility and precipitation due to charge interactions
- Guaranteed improvement in antimicrobial activity
- Automatic pH neutralization
- Enhanced fragrance retention only
Correct Answer: Risk of incompatibility and precipitation due to charge interactions
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.
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