Preparation of gels – composition and methods MCQs With Answer

Introduction: Preparation of gels – composition and methods MCQs With Answer is a focused study resource for B. Pharm students covering gel formulation principles, gelling agents, formulation steps, and evaluation techniques. This guide emphasizes key keywords such as gelling agents, hydrogels, organogels, emulgels, polymer concentration, rheology, cross-linking, gelation methods, viscosity, spreadability, drug release, and sterilization. It explores both physical and chemical gelation mechanisms, common polymers (e.g., Carbopol, HPMC, poloxamer, alginate), method selection (heat-cool, cold process, ionotropic gelation), and critical quality attributes. Simple explanations and application-oriented MCQs help reinforce practical decision-making in gel formulation and quality control. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which polymer requires neutralization with a base to form a transparent gel in aqueous systems?

• Carbopol 934
• Gelatin
• Hydroxypropyl methylcellulose (HPMC)
• Agar

Correct Answer: Carbopol 934

Q2. Which gelling mechanism is primarily responsible for poloxamer (Pluronic F127) gelation?

• Covalent cross-linking
• Ionotropic gelation
• Thermoreversible micellar gelation
• Hydrogen-bond driven chemical gelation

Correct Answer: Thermoreversible micellar gelation

Q3. Which method is most appropriate to prepare an organogel containing a lipophilic drug?

• Cold aqueous dispersion of carbomer
• Oil phase gelation using organogelator with heat and cooling
• Ionotropic gelation with calcium chloride
• Coacervation in aqueous medium

Correct Answer: Oil phase gelation using organogelator with heat and cooling

Q4. In ionotropic gelation of alginate, which cation is commonly used to cross-link and form beads or gels?

• Sodium
• Potassium
• Calcium
• Magnesium

Correct Answer: Calcium

Q5. Which evaluation parameter directly assesses the flow behavior and deformation of gels under applied stress?

• Spreadability
• Rheology (viscosity and viscoelasticity)
• pH
• Syneresis

Correct Answer: Rheology (viscosity and viscoelasticity)

Q6. Thixotropy in gels refers to which of the following behaviors?

• Permanent hardening on standing
• Time-dependent reversible shear thinning
• Immediate phase separation
• Increase in viscosity with shear

Correct Answer: Time-dependent reversible shear thinning

Q7. Which preservative consideration is most critical when formulating aqueous gels?

• Color matching with the polymer
• Compatibility with gelling agent and pH range
• High melting point
• Viscosity enhancement

Correct Answer: Compatibility with gelling agent and pH range

Q8. Emulgels are hybrid systems combining which two dosage form types?

• Suspension and liquid
• Emulsion and gel
• Tablet and gel
• Solution and ointment

Correct Answer: Emulsion and gel

Q9. Which polymer is commonly used for thermoreversible in situ gelation in ophthalmic formulations?

• Carbopol
• Pluronic F127 (poloxamer)
• Sodium alginate
• Guar gum

Correct Answer: Pluronic F127 (poloxamer)

Q10. In gel formulations, syneresis refers to:

• Increase in viscosity over time
• Release of liquid from a gel leading to contraction
• Improved spreadability
• Complete dissolution of polymer

Correct Answer: Release of liquid from a gel leading to contraction

Q11. Which technique is suitable to sterilize heat-sensitive gel formulations intended for ocular use?

• Autoclaving at 121°C
• Gamma irradiation or sterile filtration where applicable
• Dry heat sterilization
• Boiling for 30 minutes

Correct Answer: Gamma irradiation or sterile filtration where applicable

Q12. Carbopol gels typically require which pH range to achieve optimum viscosity?

• Highly acidic (pH 1–3)
• Neutral to slightly alkaline (pH 6–8)
• Strongly alkaline (pH 12–14)
• pH has no effect

Correct Answer: Neutral to slightly alkaline (pH 6–8)

Q13. Which analytical instrument is commonly used to measure gel viscosity and viscoelastic properties?

• UV-Visible spectrophotometer
• Rheometer or rotational viscometer
• HPLC
• Gas chromatograph

Correct Answer: Rheometer or rotational viscometer

Q14. Which natural polymer forms thermally reversible gels and is widely used in food and pharma?

• Agar
• Carbopol
• Polyvinylpyrrolidone (PVP)
• Poloxamer

Correct Answer: Agar

Q15. For sustained drug release from a hydrogel, which factor is most influential?

• Surface color of the gel
• Cross-link density and polymer mesh size
• Ambient light intensity
• Packaging shape

Correct Answer: Cross-link density and polymer mesh size

Q16. Bigels are formulations that combine which two phases?

• Two aqueous phases with different pH
• Hydrogel and organogel phases
• Gas and liquid phases
• Powder and tablet phases

Correct Answer: Hydrogel and organogel phases

Q17. Which cross-linking agent is commonly used for chemical cross-linking of polymers like gelatin?

• Calcium chloride
• Glutaraldehyde
• Sodium chloride
• Glycerin

Correct Answer: Glutaraldehyde

Q18. Which release mechanism is typical for small molecules diffusing from a non-degrading gel matrix?

• Zero-order release due to erosion
• Fickian diffusion-controlled release
• Enzymatic triggered burst release only
• No release occurs

Correct Answer: Fickian diffusion-controlled release

Q19. Which parameter evaluates how easily a topical gel spreads on skin?

• pH
• Spreadability (or shear work)
• Odor intensity
• Melting point

Correct Answer: Spreadability (or shear work)

Q20. Which preservative might be ineffective in highly anionic gels due to binding or inactivation?

• Parabens (methylparaben)
• Benzalkonium chloride (a cationic preservative)
• Bronopol
• Sorbic acid

Correct Answer: Benzalkonium chloride (a cationic preservative)

Q21. Which method is used to prepare drug-loaded gel beads via dripping alginate solution into calcium chloride?

• Spray drying
• Ionotropic gelation (external gelation)
• Melt granulation
• Hot-melt extrusion

Correct Answer: Ionotropic gelation (external gelation)

Q22. Which gel type is most suitable for delivering lipophilic drugs topically while enhancing penetration?

• Hydrogel
• Emulgel or organogel
• Aqueous paste
• Oral gel

Correct Answer: Emulgel or organogel

Q23. Neutralization of Carbopol with triethanolamine primarily causes which change?

• Decrease in viscosity and gel collapse
• Ionization of carboxyl groups and swelling to increase viscosity
• Complete polymer degradation
• Formation of insoluble precipitate

Correct Answer: Ionization of carboxyl groups and swelling to increase viscosity

Q24. Which factor often decreases chemical preservative efficacy in gels?

• Low water activity
• Presence of high polymer concentration that binds preservative
• Transparent appearance
• High oxygen permeability

Correct Answer: Presence of high polymer concentration that binds preservative

Q25. A gel showing rapid recovery of viscosity after shear indicates which desirable property?

• Irreversible thixotropy
• Good structural integrity and thixotropic recovery
• Permanent liquefaction
• Phase inversion on application

Correct Answer: Good structural integrity and thixotropic recovery

Q26. Which polymer is particularly useful for mucoadhesive gels due to its bioadhesive carboxyl groups?

• Sodium alginate
• Polyethylene glycol (PEG)
• Sodium chloride
• Sorbitol

Correct Answer: Sodium alginate

Q27. For semi-solid gels, what does the term “mesh size” refer to?

• Size of packaging mesh
• Average pore dimension of polymer network affecting diffusion
• Particle size of suspended drug only
• Thickness of the gel container

Correct Answer: Average pore dimension of polymer network affecting diffusion

Q28. Which solvent system is commonly used to prepare hydrogels for water-soluble drugs?

• Pure oil phase
• Aqueous solvent system (water or buffered water)
• Non-polar organic solvents like hexane
• Supercritical CO2 only

Correct Answer: Aqueous solvent system (water or buffered water)

Q29. What is a common stability issue for gels containing natural polymers like gelatin?

• Excessively low pH only
• Microbial spoilage and enzymatic degradation
• Instant chemical cross-linking making unusable
• Complete resistance to temperature changes

Correct Answer: Microbial spoilage and enzymatic degradation

Q30. Which parameter is essential to report in a gel formulation to predict topical bioavailability?

• Package color
• Viscosity, drug content, and pH
• Manufacturer’s logo size
• Ambient humidity only

Correct Answer: Viscosity, drug content, and pH

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