Excipients used in liquid formulations MCQs With Answer

Excipients used in liquid formulations MCQs With Answer help B. Pharm students master how functional additives optimize stability, safety, and patient acceptability in liquid dosage forms. In solutions, suspensions, emulsions, and syrups, excipients such as solvents, co-solvents, buffers, preservatives, antioxidants, chelating agents, surfactants, wetting agents, suspending agents, viscosity modifiers, sweeteners, flavors, and colorants control solubility, pH, rheology, osmolality, microbial protection, and taste-masking. Selection depends on drug properties, pKa, HLB, ionic compatibility, target route (oral, ophthalmic, parenteral), patient factors (pediatrics, diabetics), and regulatory status (GRAS, IIG, pharmacopeial monographs). Understanding interactions (e.g., preservative–surfactant, metal-catalyzed oxidation), pH windows, and safety limits is critical for robust formulation design. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the primary function of a co-solvent in an aqueous liquid formulation?

• Increase solubility of poorly water-soluble drugs
• Adjust tonicity
• Provide sweetness
• Prevent oxidation

Correct Answer: Increase solubility of poorly water-soluble drugs

Q2. Which preservative is most suitable for acidic syrups (pH 2.5–4.5) due to a higher fraction of undissociated acid?

• Sodium benzoate
• Potassium sorbate
• Benzalkonium chloride
• Chlorobutanol

Correct Answer: Sodium benzoate

Q3. Which buffer system minimizes the risk of calcium precipitation in oral liquids?

• Acetate buffer (acetic acid/sodium acetate)
• Phosphate buffer (monobasic/dibasic)
• Borate buffer (boric acid/sodium borate)
• Citrate buffer (citric acid/sodium citrate)

Correct Answer: Acetate buffer (acetic acid/sodium acetate)

Q4. Which antioxidant is oil-soluble and preferred for protecting the oil phase in emulsions?

• Butylated hydroxytoluene (BHT)
• Ascorbic acid
• Sodium metabisulfite
• Disodium EDTA

Correct Answer: Butylated hydroxytoluene (BHT)

Q5. Which chelating agent is commonly added to enhance antioxidant effectiveness by binding trace metals?

• Disodium EDTA
• Citric acid
• Butylated hydroxyanisole (BHA)
• Sodium sulfite

Correct Answer: Disodium EDTA

Q6. In suspensions, which excipient can act as a flocculating agent by compressing the electrical double layer?

• Aluminum chloride
• Polysorbate 80
• Propylene glycol
• Sodium chloride

Correct Answer: Aluminum chloride

Q7. Which rheological behavior is most desirable for oral suspensions to resist sedimentation during storage yet pour easily?

• Newtonian
• Plastic
• Pseudoplastic with thixotropy
• Dilatant

Correct Answer: Pseudoplastic with thixotropy

Q8. Which wetting agent is suitable for dispersing hydrophobic drug particles in an aqueous suspension?

• Polysorbate 80 (Tween 80)
• Sorbitan monooleate (Span 80)
• Mineral oil
• Talc

Correct Answer: Polysorbate 80 (Tween 80)

Q9. Which sweetener is preferred for sugar-free oral liquids for diabetic patients?

• Sucralose
• Sucrose
• High-fructose corn syrup
• Glucose

Correct Answer: Sucralose

Q10. Which is NOT a primary function of glycerin at typical concentrations in oral solutions?

• Co-solvent
• Humectant
• Preservative at typical concentrations
• Viscosity modifier

Correct Answer: Preservative at typical concentrations

Q11. According to US FDA guidance, the maximum alcohol content allowed in oral solutions for children under 6 years is:

• 0.5% v/v
• 1% v/v
• 5% v/v
• 10% v/v

Correct Answer: 0.5% v/v

Q12. Why is polysorbate 80 commonly added to protein or peptide solutions?

• Reduce surface adsorption and aggregation
• Increase osmolarity
• Adjust pH
• Provide color

Correct Answer: Reduce surface adsorption and aggregation

Q13. Which tonicity adjuster is most commonly used in ophthalmic solutions?

• Sodium chloride
• Potassium permanganate
• Calcium carbonate
• Sodium bicarbonate

Correct Answer: Sodium chloride

Q14. Which excipient can inactivate benzalkonium chloride via ionic incompatibility?

• Sodium lauryl sulfate
• Disodium EDTA
• Sorbitol
• Propylene glycol

Correct Answer: Sodium lauryl sulfate

Q15. Above the cloud point of a nonionic surfactant, which issue is most likely?

• Loss of micellar solubilization due to phase separation
• Increased antimicrobial efficacy
• Increased viscosity
• Improved wetting

Correct Answer: Loss of micellar solubilization due to phase separation

Q16. To prepare a stable o/w emulsion with a required HLB around 12–15, which emulsifier is most appropriate?

• Polysorbate 80 (Tween 80)
• Sorbitan monooleate (Span 80)
• Sorbitan monostearate (Span 60)
• Beeswax

Correct Answer: Polysorbate 80 (Tween 80)

Q17. Which suspending agent exhibits pseudoplastic flow and good stability over a wide pH range?

• Xanthan gum
• Sodium alginate
• Carbomer (unneutralized)
• Bentonite

Correct Answer: Xanthan gum

Q18. Which preservative is contraindicated in neonates due to the risk of “gasping syndrome”?

• Benzyl alcohol
• Sorbic acid
• Methylparaben
• Potassium sorbate

Correct Answer: Benzyl alcohol

Q19. A common adverse effect of sorbitol in oral liquids is:

• Osmotic laxative effect
• Nephrotoxicity
• Photosensitivity
• Methemoglobinemia

Correct Answer: Osmotic laxative effect

Q20. Which class of colorants is typically selected for aqueous oral solutions to meet regulatory standards?

• Water-soluble FD&C dyes
• Aluminum lakes only
• Inorganic pigments only
• Oil-soluble dyes only

Correct Answer: Water-soluble FD&C dyes

Q21. What is the primary role of sodium metabisulfite in aqueous formulations?

• Antioxidant
• Buffer
• Flocculating agent
• Sweetener

Correct Answer: Antioxidant

Q22. In ophthalmic solutions, EDTA is often included to:

• Enhance preservative effectiveness by chelating metals
• Increase tonicity
• Act as a viscosity enhancer
• Provide flavor

Correct Answer: Enhance preservative effectiveness by chelating metals

Q23. Which co-solvent is generally preferred for pediatric oral liquids due to lower toxicity?

• Glycerol
• Ethanol
• Propylene glycol
• Dimethyl sulfoxide

Correct Answer: Glycerol

Q24. Which buffer system is commonly used to maintain physiological pH in parenteral solutions?

• Phosphate buffer
• Borate buffer
• Tartarate buffer
• Lactate buffer

Correct Answer: Phosphate buffer

Q25. To preserve flavored syrups without relying on low pH, which preservative system is most appropriate?

• Methylparaben + propylparaben combination
• Sodium benzoate alone
• Potassium sorbate alone
• Benzalkonium chloride alone

Correct Answer: Methylparaben + propylparaben combination

Q26. To formulate a stable w/o emulsion, which emulsifier is most suitable?

• Sorbitan monooleate (Span 80)
• Polysorbate 80 (Tween 80)
• Sodium lauryl sulfate
• Polysorbate 20

Correct Answer: Sorbitan monooleate (Span 80)

Q27. What is the main purpose of adding a humectant to oral gels or syrups?

• Reduce moisture loss and prevent drying
• Increase sweetness
• Provide preservative action
• Adjust tonicity

Correct Answer: Reduce moisture loss and prevent drying

Q28. Which statement about viscosity modifiers in liquid formulations is TRUE?

• Hydroxypropyl methylcellulose (HPMC) can increase viscosity and stabilize suspensions
• Sodium chloride is a common viscosity enhancer
• PEG 400 markedly increases viscosity at very low concentrations
• Polysorbate 80 significantly increases gel strength

Correct Answer: Hydroxypropyl methylcellulose (HPMC) can increase viscosity and stabilize suspensions

Q29. To mitigate metal-catalyzed oxidation of catecholamines in solution, which combination is most effective?

• Sodium metabisulfite + EDTA
• Ascorbic acid alone
• BHT alone
• Potassium sorbate + citric acid

Correct Answer: Sodium metabisulfite + EDTA

Q30. Which formulation scenario most risks drug precipitation upon dilution in the GI tract?

• High ethanol–propylene glycol co-solvent system
• Sodium chloride as a tonicity adjuster
• EDTA as a chelator
• Xanthan gum as a thickener

Correct Answer: High ethanol–propylene glycol co-solvent system

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