Polyethylene glycols and sorbitols in formulations MCQs With Answer

Introduction: Polyethylene glycols and sorbitols are versatile excipients widely used in pharmaceutical formulations. Polyethylene glycols (PEGs) act as solubilizers, plasticizers, ointment bases, and vehicles for drug delivery; their function depends on molecular weight. Sorbitols (liquid and crystalline) serve as humectants, sweetening agents, osmotic agents, and bulking agents in syrups, oral solid dosage forms, and chewables. Understanding their physicochemical properties, compatibility, stability, toxicity, and regulatory grades is essential for formulation design, quality control, and patient safety. This concise guide emphasizes practical applications, selection criteria, and common analytical considerations. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What property of polyethylene glycol (PEG) primarily varies with its molecular weight?

• Color
• Melting point and viscosity
• Odor
• pH

Correct Answer: Melting point and viscosity

Q2. Which PEG grade is most commonly used as an ointment base due to its semi-solid consistency?

• PEG 200
• PEG 400
• PEG 1000–1450
• PEG 8000

Correct Answer: PEG 1000–1450

Q3. Sorbitol functions in oral liquid formulations primarily as which of the following?

• Preservative
• Humectant and sweetener
• Disintegrant
• Lubricant

Correct Answer: Humectant and sweetener

Q4. Which statement about PEGylation is correct?

• It decreases molecular weight of drugs
• It improves drug solubility and circulation half-life
• It is used to color tablets
• It always increases drug toxicity

Correct Answer: It improves drug solubility and circulation half-life

Q5. Which analytical test is important for PEG raw materials in quality control?

• Assay by HPLC and average molecular weight by GPC
• Microbial limit test only
• Melting point only
• Taste evaluation

Correct Answer: Assay by HPLC and average molecular weight by GPC

Q6. Liquid sorbitol solution is commonly prepared as which concentration for syrups?

• 10% w/v
• 50% w/v
• 70% w/v
• 100% w/v

Correct Answer: 70% w/v

Q7. Which of the following is a common incompatibility concern with PEG in formulations?

• Oxidative degradation with peroxides
• Acid-catalyzed hydrolysis of PEG backbone
• PEG forms explosive peroxides on storage
• PEG reacts with metals to form insoluble salts

Correct Answer: Oxidative degradation with peroxides

Q8. Sorbitol is preferred over sucrose in diabetic formulations because:

• It has higher caloric value
• It is non-cariogenic and has lower glycemic response
• It is cheaper than water
• It causes stronger osmotic diarrhea

Correct Answer: It is non-cariogenic and has lower glycemic response

Q9. A key role of PEG 400 in liquid oral formulations is:

• Major preservative
• Solubilizer and cosolvent for poorly soluble drugs
• Primary flavoring agent
• Disintegrant

Correct Answer: Solubilizer and cosolvent for poorly soluble drugs

Q10. What is a potential adverse effect of high oral intake of sorbitol?

• Hypoglycemia
• Laxative effect and osmotic diarrhea
• Hepatotoxicity
• Severe hypokalemia

Correct Answer: Laxative effect and osmotic diarrhea

Q11. Which excipient property is improved by adding PEG as a plasticizer to polymer films?

• Water vapor permeability only
• Decreased flexibility
• Increased flexibility and reduced brittleness
• Increased tensile strength without flexibility change

Correct Answer: Increased flexibility and reduced brittleness

Q12. Which type of sorbitol is commonly used in chewable tablets and solid oral dosage forms?

• Sorbitol solution 70% only
• D-sorbitol crystalline powder (sorbitol DC)
• Polysorbitol complex
• Sorbitan monooleate

Correct Answer: D-sorbitol crystalline powder (sorbitol DC)

Q13. Which stability concern applies to sorbitol-containing oral syrups?

• High volatility leading to evaporation
• Maillard reaction with primary amines and color change
• Rapid polymerization to insoluble gum
• Spontaneous crystallization into PEG

Correct Answer: Maillard reaction with primary amines and color change

Q14. PEGs are classified by molecular weight. Which is true for PEG 2000 compared to PEG 400?

• PEG 2000 is more liquid than PEG 400
• PEG 2000 is solid or waxy and has higher melting point than PEG 400
• PEG 2000 has lower viscosity than PEG 400
• PEG 2000 is more volatile

Correct Answer: PEG 2000 is solid or waxy and has higher melting point than PEG 400

Q15. In parenteral formulations, a major consideration when using PEG is:

• PEG taste masking
• Possible immunogenicity and hypersensitivity for some PEGylated products
• PEG extensively reduces pH below 2
• PEG causes immediate precipitation of proteins

Correct Answer: Possible immunogenicity and hypersensitivity for some PEGylated products

Q16. Sorbitol as an osmotic agent is used in which type of preparation?

• Sustained-release matrix tablets
• Osmotic laxative solutions and colonic lavage
• Topical antifungal creams
• Injectable oil-based depot formulations

Correct Answer: Osmotic laxative solutions and colonic lavage

Q17. Which reaction pathway can degrade PEG under accelerated oxidative conditions?

• Chain scission by free radical oxidation forming alcohols and acids
• Complete polymerization to higher polymers
• Conversion to sorbitol
• PEG is inert and does not degrade

Correct Answer: Chain scission by free radical oxidation forming alcohols and acids

Q18. When formulating chewable tablets for pediatrics, sorbitol is chosen mainly because:

• It accelerates tablet disintegration
• It provides sweetness, bulk and non-cariogenic properties
• It is highly hygroscopic causing rapid degradation
• It reacts with active drugs to form salts

Correct Answer: It provides sweetness, bulk and non-cariogenic properties

Q19. Which excipient interaction is a concern when combining PEG with certain drugs?

• PEG can form eutectic mixtures or enhance drug solubility unpredictably
• PEG converts drugs into volatile gases
• PEG universally reduces drug potency by 90%
• PEG neutralizes all acidic drugs

Correct Answer: PEG can form eutectic mixtures or enhance drug solubility unpredictably

Q20. Which analytical method is commonly used to quantify sorbitol content in syrups?

• UV-visible spectrophotometry at 280 nm
• Gas chromatography after derivatization or HPLC with RI detection
• NMR only with no chromatography
• TLC with iodine visualization

Correct Answer: Gas chromatography after derivatization or HPLC with RI detection

Q21. Which statement about taste and mouthfeel is true for PEG in oral formulations?

• Low-molecular-weight PEGs are often bitter
• PEGs are flavorless and can impart a slippery mouthfeel at higher concentrations
• PEGs always improve sweetness
• PEGs cause strong astringency

Correct Answer: PEGs are flavorless and can impart a slippery mouthfeel at higher concentrations

Q22. Sorbitol dihydrate vs anhydrous forms: which is an important formulation consideration?

• Hydrate form has lower bulk density and can affect tablet weight and moisture
• Anhydrous form always crystallizes into PEG
• Hydrate form is more volatile
• There is no difference for any formulation parameter

Correct Answer: Hydrate form has lower bulk density and can affect tablet weight and moisture

Q23. PEGs are often designated by a number (e.g., PEG 400). That number represents:

• Average molecular weight approximately in daltons
• pH of a 1% solution
• Viscosity in cP exactly
• Percentage purity

Correct Answer: Average molecular weight approximately in daltons

Q24. Which regulatory or safety consideration is relevant for sorbitol use in pediatric syrups?

• Labeling for potential laxative effect at high doses
• Mandatory use of sorbitol only in adults
• Sorbitol is banned in all OTC products
• No warnings are necessary

Correct Answer: Labeling for potential laxative effect at high doses

Q25. For topical creams, PEGs can be used as which of the following?

• Emulsifier, solvent, and hydrophilic ointment base
• Primary antimicrobial preservative only
• Only as a fragrance
• As an oil phase to replace mineral oil

Correct Answer: Emulsifier, solvent, and hydrophilic ointment base

Q26. Which storage condition should be avoided for sorbitol-containing products to maintain stability?

• Protect from high humidity and microbial contamination
• Store at sub-zero temperatures always
• Expose to strong UV light to sterilize
• Store in open containers to equilibrate

Correct Answer: Protect from high humidity and microbial contamination

Q27. Which PEG variant is most suitable as a solvent in soft-gel fill formulations?

• PEG 6000
• PEG 400
• PEG 20,000
• PEG solid wax

Correct Answer: PEG 400

Q28. A formulation scientist wants to reduce hygroscopicity of a sorbitol-containing tablet. Which approach is appropriate?

• Increase storage temperature
• Add moisture scavengers or use protective coatings
• Replace sorbitol with sodium chloride
• Remove all excipients

Correct Answer: Add moisture scavengers or use protective coatings

Q29. PEGs can affect drug release from matrix tablets by:

• Functioning as hydrophilic pore-formers to increase release rate
• Completely preventing any drug release
• Converting drug into gas
• Only changing tablet color

Correct Answer: Functioning as hydrophilic pore-formers to increase release rate

Q30. Which safety test is critical for PEGs used in parenteral formulations?

• Pyrogen/endotoxin testing and residual solvent analysis
• Only pH testing
• Only taste testing
• No testing required for parenteral use

Correct Answer: Pyrogen/endotoxin testing and residual solvent analysis

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