Preparation of gels MCQs With Answer

Preparation of gels MCQs With Answer provides B. Pharm students a focused review of gel formulation principles, gelling agents, preparation methods, and evaluation techniques. This concise, keyword-rich introduction covers polymers (Carbopol, HPMC, xanthan), hydrogel vs organogel systems, rheology, pH adjustment, neutralization, cross-linking, preservatives, solvents, and factors affecting stability and drug release. Emphasis is on practical steps: dispersion, hydration, heating/cooling, fusion, and equipment like Brookfield viscometer. Understanding these concepts helps in designing topical and controlled-release gel formulations and troubleshooting physicochemical issues like syneresis and thixotropy. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which polymer is commonly neutralized with triethanolamine to form a clear carbomer gel?

• Hydroxypropyl methylcellulose
• Carbopol 940
• Xanthan gum
• Sodium alginate

Correct Answer: Carbopol 940

Q2. Which method is most suitable for preparing water-soluble polymer gels like HPMC?

• Fusion method involving oil phase
• Direct dispersion and hydration in cold water
• Emulsification with high shear
• Spray drying

Correct Answer: Direct dispersion and hydration in cold water

Q3. Thixotropy in gels refers to:

• Permanent hardening on standing
• Viscosity increase with shear
• Reversible decrease in viscosity on shearing
• Phase separation into layers

Correct Answer: Reversible decrease in viscosity on shearing

Q4. Which parameter is measured by a Brookfield viscometer during gel evaluation?

• pH
• Viscosity
• Drug potency
• Surface tension

Correct Answer: Viscosity

Q5. Which gelling agent forms gels via ionic cross-linking with multivalent cations?

• Carbopol
• Methylcellulose
• Alginate
• Polyethylene glycol

Correct Answer: Alginate

Q6. Organogels are characterized by:

• Water as continuous phase
• Organic solvent or oil as continuous phase
• Only ionic polymers
• Being sterile without preservatives

Correct Answer: Organic solvent or oil as continuous phase

Q7. Which factor most strongly affects drug release from topical gels?

• Container color
• Rheological properties and polymer network density
• Ambient humidity only
• Manufacturer logo

Correct Answer: Rheological properties and polymer network density

Q8. Syneresis in gel systems means:

• Increased elasticity on agitation
• Separation of liquid from the gel network
• Rapid microbial growth
• pH becoming neutral over time

Correct Answer: Separation of liquid from the gel network

Q9. Which preservative is commonly used in aqueous gels to prevent microbial contamination?

• Chloroform
• Parabens (methylparaben/propylparaben)
• Sodium chloride
• Calcium carbonate

Correct Answer: Parabens (methylparaben/propylparaben)

Q10. Neutralization of Carbopol causes gelation because:

• Polymer chains depolymerize
• Ionization leads to electrostatic repulsion and swelling
• It causes precipitation of polymer
• It removes water from the system

Correct Answer: Ionization leads to electrostatic repulsion and swelling

Q11. Which test assesses spreadability of a topical gel?

• pH meter reading
• Measuring diameter under weight on glass slide
• Determining microbial count
• UV absorbance of the gel

Correct Answer: Measuring diameter under weight on glass slide

Q12. Which solvent or co-solvent commonly improves solubility of lipophilic drugs in gels?

• PBS buffer only
• Ethanol or propylene glycol
• Pure water without additives
• Glycerin only

Correct Answer: Ethanol or propylene glycol

Q13. In the fusion method for gels, which component is heated?

• Only the aqueous phase
• The gel-forming solid or waxy components in oil phase
• Active drug only
• The final gel is not heated at all

Correct Answer: The gel-forming solid or waxy components in oil phase

Q14. Which property is critical for hydrogel applications in wound dressings?

• High electrical conductivity
• Moisture retention and biocompatibility
• Opaque appearance
• Permanent stiffness

Correct Answer: Moisture retention and biocompatibility

Q15. Which polymer provides thermoreversible gelation (gel on cooling) commonly used in topical gels?

• Poloxamer (Pluronic)
• Carbomer
• Sodium alginate
• Polyvinylpyrrolidone

Correct Answer: Poloxamer (Pluronic)

Q16. A common reason for cloudy gel appearance is:

• Complete polymer hydration
• Phase separation or insoluble polymer particles
• Proper neutralization of Carbopol
• Low viscosity

Correct Answer: Phase separation or insoluble polymer particles

Q17. Which analytical parameter indicates gel stability against microbial growth?

• Sieve analysis
• Preservative efficacy test (challenge test)
• Drop test
• Refractive index alone

Correct Answer: Preservative efficacy test (challenge test)

Q18. Electrolytes added to ionic gels (e.g., alginate) can:

• Always decrease gel strength
• Cause ionic cross-linking and alter gel firmness
• Have no effect on gelation
• Convert gels into powders

Correct Answer: Cause ionic cross-linking and alter gel firmness

Q19. The term ‘organogelator’ refers to:

• A polymer that gels aqueous systems only
• A molecule that induces gelation in organic solvents or oils
• An enzyme used in gel cross-linking
• A surfactant used to emulsify oils

Correct Answer: A molecule that induces gelation in organic solvents or oils

Q20. Which technique helps reduce air entrapment when preparing gels?

• High temperature fusion without cooling
• Slow addition with gentle stirring and deaeration under vacuum
• Vigorous high-speed homogenization only
• Immediate packaging without mixing

Correct Answer: Slow addition with gentle stirring and deaeration under vacuum

Q21. Which excipient acts as both humectant and co-solvent in gels?

• Triethanolamine
• Propylene glycol
• Sodium hydroxide
• Calcium chloride

Correct Answer: Propylene glycol

Q22. When formulating acidic drugs in Carbopol gels, what precaution is needed?

• No neutralization required
• pH adjustment to maintain drug stability and polymer viscosity
• Use strong oxidizers to stabilize the drug
• Remove water completely

Correct Answer: pH adjustment to maintain drug stability and polymer viscosity

Q23. How does cross-linking density of a polymer network affect gel swelling?

• Higher cross-linking increases swelling indefinitely
• Higher cross-linking decreases swelling capacity
• Cross-linking has no effect on swelling
• Cross-linking converts gels to solutions

Correct Answer: Higher cross-linking decreases swelling capacity

Q24. For ophthalmic gels, which property is most critical?

• Non-irritancy and isotonicity
• High viscosity above 50,000 cP
• Strong coloring agents
• Presence of heavy metal ions

Correct Answer: Non-irritancy and isotonicity

Q25. Which instrument is commonly used to study gel rheology under controlled shear?

• Spectrophotometer
• Rheometer
• pH meter
• Analytical balance

Correct Answer: Rheometer

Q26. A gelling agent derived from seaweed used in pharmaceutical gels is:

• Gelatin only
• Agar or carrageenan
• Polyethylene glycol
• Silicon oil

Correct Answer: Agar or carrageenan

Q27. Which approach enhances penetration of drug through skin from a gel?

• Decrease drug solubility in vehicle
• Use of penetration enhancers like terpenes or propylene glycol
• Removing all water to create a dry gel
• Using large polymer molecules to trap drug

Correct Answer: Use of penetration enhancers like terpenes or propylene glycol

Q28. Which phenomenon indicates inadequate preservation in an aqueous gel during stability testing?

• Consistent pH and color
• Microbial growth detected in challenge test
• Stable viscosity over time
• Improved spreadability

Correct Answer: Microbial growth detected in challenge test

Q29. Carbopol gels typically require what final pH range for optimal clarity and viscosity?

• Below pH 2
• Around neutral to slightly alkaline (pH 6–7.5)
• pH above 12
• No pH adjustment needed

Correct Answer: Around neutral to slightly alkaline (pH 6–7.5)

Q30. What is the main advantage of using hydrogels for controlled drug delivery?

• They always cause irritation
• They provide a hydrated matrix enabling sustained release and biocompatibility
• They prevent any drug diffusion
• They are completely impermeable

Correct Answer: They provide a hydrated matrix enabling sustained release and biocompatibility

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