Use of oils in herbal cosmetic formulations MCQs With Answer

Introduction: Use of oils in herbal cosmetic formulations MCQs With Answer is a focused quiz collection designed for M.Pharm students studying Herbal Cosmetics (MPG 204T). This set explores the pharmacotechnical and phytochemical aspects of fixed and essential oils used in topical preparations — covering composition, extraction, analytical quality control (peroxide, saponification, iodine values), stability, oxidative rancidity, penetration enhancement, emollient/occlusive actions, HLB selection for emulsions, and safety issues like phototoxicity and allergenicity. Questions emphasize formulation decisions, testing methodologies, and rationale behind selecting specific carrier oils for varied skin types and delivery goals, preparing students for both exams and practical formulation work.

Q1. Which parameter best indicates the degree of unsaturation in a fixed oil and is critical for predicting its susceptibility to oxidative rancidity?

• Peroxide value
• Saponification value
• Iodine value
• Acid value

Correct Answer: Iodine value

Q2. Which analytical test directly measures primary oxidation products in oils and is commonly used for quality control of herbal cosmetic raw materials?

• Anisidine value
• Free fatty acid (acid) value
• Peroxide value
• Saponification value

Correct Answer: Peroxide value

Q3. A formulator wants an oil with high occlusivity and strong barrier enhancement for very dry skin — which oil is most appropriate?

• Jojoba oil
• Mineral oil
• Sunflower oil (high linoleic)
• Grapeseed oil

Correct Answer: Mineral oil

Q4. Which fixed oil is actually a liquid wax ester and is prized in herbal cosmetics for its stability and close mimicking of skin sebum?

• Coconut oil
• Jojoba oil
• Almond oil
• Olive oil

Correct Answer: Jojoba oil

Q5. For an oil-in-water emulsion, which approach helps incorporate a non-polar herbal oil while maintaining emulsion stability?

• Use a high-HLB emulsifier and pre-mix oil with emulsifier
• Add the oil directly into the aqueous phase at room temperature
• Replace water with an alcohol co-solvent permanently
• Always use essential oils instead of fixed oils

Correct Answer: Use a high-HLB emulsifier and pre-mix oil with emulsifier

Q6. Which fatty acid predominance in a carrier oil is most associated with comedogenic potential and strong occlusive action?

• High linoleic acid content
• High oleic acid content
• High lauric and myristic acid content
• High alpha-linolenic acid content

Correct Answer: High lauric and myristic acid content

Q7. Cold-pressed (expeller-pressed) extraction of carrier oils is preferred for many herbal cosmetics because it:

• Yields higher peroxide values than solvent extraction
• Preserves heat-sensitive phytochemicals like tocopherols and phytosterols
• Removes all impurities and allergens
• Is the only method that legally qualifies as cosmetic-grade

Correct Answer: Preserves heat-sensitive phytochemicals like tocopherols and phytosterols

Q8. Which oil would be least suitable in a photoprotective herb-based sunscreen due to phototoxic constituents?

• Olive oil
• Cold-pressed bergamot oil (contains bergapten)
• Rice bran oil
• Argan oil

Correct Answer: Cold-pressed bergamot oil (contains bergapten)

Q9. In a stability study, which combination of tests best assesses oxidative deterioration of an oil-containing herbal cream?

• pH measurement and viscosity profiling
• Peroxide value, anisidine value and sensory (odor) assessment
• Microbial load and patch testing
• Density and refractive index

Correct Answer: Peroxide value, anisidine value and sensory (odor) assessment

Q10. Which oil is especially rich in gamma-linolenic acid (GLA) and commonly used in formulations targeting inflammation and dermatitis?

• Sunflower oil
• Evening primrose oil
• Coconut oil
• Jojoba oil

Correct Answer: Evening primrose oil

Q11. For enhancing transdermal delivery of a hydrophilic herbal active, which oil-related strategy is most appropriate?

• Use highly occlusive oil to prevent penetration
• Incorporate permeation enhancers (e.g., oleic acid) or use nanoemulsions with oil phase
• Use only volatile essential oils without carriers
• Replace oil with glycerin to improve partitioning

Correct Answer: Incorporate permeation enhancers (e.g., oleic acid) or use nanoemulsions with oil phase

Q12. Saponification value of an oil helps the cosmetic formulator to:

• Predict its comedogenicity on skin
• Estimate average molecular weight of triglycerides and soap requirement
• Measure peroxide concentration
• Quantify essential oil content

Correct Answer: Estimate average molecular weight of triglycerides and soap requirement

Q13. Which natural antioxidant is commonly added to herbal oil formulations to delay rancidity while being acceptable in cosmeceutical applications?

• Butylated hydroxyanisole (BHA) synthetic only
• Tocopherol (vitamin E)
• Hydroquinone
• Formaldehyde releasers

Correct Answer: Tocopherol (vitamin E)

Q14. A high peroxide value combined with a low anisidine value indicates which stage of oil oxidation?

• Advanced secondary oxidation predominating
• Initial/primary oxidation predominating with hydroperoxides present
• Complete rancidity with polymerization
• Oil is freshly refined and unoxidized

Correct Answer: Initial/primary oxidation predominating with hydroperoxides present

Q15. Selecting a carrier oil for acne-prone skin, which characteristic is most desirable?

• High comedogenic index and saturated fat content
• High linoleic:oleic ratio and non-greasy skin feel
• Strong fragrance and essential oil concentration
• High percentage of long-chain saturated triglycerides

Correct Answer: High linoleic:oleic ratio and non-greasy skin feel

Q16. Incorporation of essential oils into a herbal cream requires attention to solubility; essential oils are best solubilized in the formulation by:

• Dissolving directly into the aqueous phase
• Pre-diluting in a compatible fixed oil or solubilizer and adding to oil phase
• Heating the aqueous phase above 90°C
• Neutralizing with alkali before addition

Correct Answer: Pre-diluting in a compatible fixed oil or solubilizer and adding to oil phase

Q17. Which test is most appropriate to detect volatile contaminants or residual solvents in cold-pressed botanical carrier oils?

• Fourier-transform infrared spectroscopy (FTIR)
• Gas chromatography with appropriate detectors (GC-FID or GC-MS)
• Saponification value determination
• Viscosity and refractive index

Correct Answer: Gas chromatography with appropriate detectors (GC-FID or GC-MS)

Q18. Rice bran oil is favored in anti-aging herbal cosmetics mainly because it contains:

• High amounts of lauric acid and medium-chain triglycerides
• Gamma-oryzanol, tocopherols and tocotrienols with antioxidant activity
• Excessive trans fats for skin tightening
• High benzyl alcohol content as natural preservative

Correct Answer: Gamma-oryzanol, tocopherols and tocotrienols with antioxidant activity

Q19. When formulating a water-in-oil (W/O) herbal emulsion, which HLB characteristic is required of the emulsifier blend?

• High HLB (10–18) to favor W/O emulsions
• Low HLB (3–6) to favor W/O emulsions
• HLB is irrelevant for W/O systems
• Extremely high HLB (>20) is mandatory

Correct Answer: Low HLB (3–6) to favor W/O emulsions

Q20. Microencapsulation of oils in herbal cosmetic actives primarily provides which formulation advantages?

• Increased immediate volatility and stronger odor release
• Improved oxidative stability, controlled release and reduced skin irritation
• Higher saponification value and increased rancidity
• Replacement of fixed oils with inorganic solvents

Correct Answer: Improved oxidative stability, controlled release and reduced skin irritation

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