Coacervation MCQs With Answer

Coacervation MCQs With Answer: This focused introduction helps B.Pharm students master complex and simple coacervation, an essential microencapsulation technique in pharmaceutics. It covers principles of phase separation, polymer interactions (e.g., gelatin–gum arabic), pH and ionic strength effects, thermodynamics, crosslinking, and formulation strategies to improve encapsulation efficiency, particle size control and controlled drug release. Practical applications include taste masking, stability enhancement, and targeted delivery. These MCQs emphasize mechanism, process variables, characterization methods and troubleshooting to prepare you for exams and research. Concise explanations train analytical thinking for formulation design and quality control. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What is complex coacervation in pharmaceutics?

• A phase separation process driven by electrostatic interaction between oppositely charged polymers leading to a polymer-rich coacervate phase
• A thermal decomposition of a polymer leading to drug release
• A solvent evaporation technique for nanoparticle formation
• An enzymatic degradation of wall materials in microcapsules

Correct Answer: A phase separation process driven by electrostatic interaction between oppositely charged polymers leading to a polymer-rich coacervate phase

Q2. Which pair of polymers is classically used for complex coacervation?

• Gelatin and gum arabic
• Polyethylene glycol and polyvinyl alcohol
• Polylactic acid and polystyrene
• Chitosan and cellulose acetate

Correct Answer: Gelatin and gum arabic

Q3. What primarily drives simple coacervation?

• Electrostatic attraction between oppositely charged polymers
• Reduction of polymer solubility by addition of a desolvating agent
• Covalent crosslinking of wall polymers
• High shear homogenization

Correct Answer: Reduction of polymer solubility by addition of a desolvating agent

Q4. During coacervation, what is the “coacervate phase”?

• A polymer-rich liquid droplet phase separated from the continuous phase
• A solid precipitate of drug crystals
• A gaseous phase formed during drying
• A uniformly dispersed polymer solution

Correct Answer: A polymer-rich liquid droplet phase separated from the continuous phase

Q5. How does pH affect complex coacervation using gelatin and gum arabic?

• pH alters polymer charge; optimal coacervation occurs near the isoelectric point of gelatin where opposite charges attract
• pH has no effect on coacervation
• Higher pH always enhances coacervation regardless of polymers
• Lower pH always prevents coacervation

Correct Answer: pH alters polymer charge; optimal coacervation occurs near the isoelectric point of gelatin where opposite charges attract

Q6. Which factor decreases coacervate formation in a charge-driven system?

• High ionic strength due to added salts
• Optimal polymer charge stoichiometry
• Proper pH adjustment for charge neutralization
• Adequate polymer concentration

Correct Answer: High ionic strength due to added salts

Q7. What is the main purpose of crosslinking coacervate shells?

• Strengthen the shell to prevent coalescence and control release
• Increase solubility of the core material
• Enhance dissolution rate of the drug inside
• Convert liquid droplets into gas bubbles

Correct Answer: Strengthen the shell to prevent coalescence and control release

Q8. Which crosslinking agent is commonly used for gelatin microcapsules?

• Glutaraldehyde
• Sodium chloride
• Polyethylene glycol
• Ethanol

Correct Answer: Glutaraldehyde

Q9. Which process step typically follows coacervate deposition on dispersed cores?

• Crosslinking to harden the deposited shell
• Lyophilization without stabilization
• Immediate dissolution in water
• High-temperature annealing

Correct Answer: Crosslinking to harden the deposited shell

Q10. What is encapsulation efficiency in coacervation?

• The percentage of initial core material successfully entrapped within the microcapsules
• The thickness of the coacervate shell in micrometers
• The viscosity of the coacervate phase
• The time taken for phase separation

Correct Answer: The percentage of initial core material successfully entrapped within the microcapsules

Q11. Which characterization technique is used to examine microcapsule surface morphology?

• Scanning electron microscopy (SEM)
• UV-Visible spectroscopy
• Gas chromatography
• Volumetric titration

Correct Answer: Scanning electron microscopy (SEM)

Q12. What effect does increasing temperature often have on coacervation?

• It can change polymer solubility and interaction strength, sometimes disrupting coacervate formation
• It invariably increases coacervate yield
• Temperature has no effect on coacervation
• It always converts coacervates into solids

Correct Answer: It can change polymer solubility and interaction strength, sometimes disrupting coacervate formation

Q13. What is “associative coacervation”?

• Phase separation due to attractive interactions between different polymers forming complexes
• Phase separation caused by polymer–polymer repulsion
• Thermally induced polymer crystallization
• Coacervation induced by enzymatic crosslinking

Correct Answer: Phase separation due to attractive interactions between different polymers forming complexes

Q14. Which parameter is crucial for controlling microcapsule size?

• Agitation speed during dispersion
• Color of the polymers
• Type of packaging used
• Ambient light intensity

Correct Answer: Agitation speed during dispersion

Q15. What describes “segregative coacervation”?

• Phase separation where polymers repel and separate into two polymer-rich phases
• Coacervation caused by opposite charges attracting
• Crosslinking-driven capsule hardening
• Encapsulation by solvent evaporation

Correct Answer: Phase separation where polymers repel and separate into two polymer-rich phases

Q16. Which analytical measurement indicates surface charge of coacervate droplets?

• Zeta potential
• Melting point
• Refractive index
• Osmotic pressure

Correct Answer: Zeta potential

Q17. Why is stoichiometry of charged polymers important in complex coacervation?

• Correct charge balance maximizes attraction and coacervate yield
• It determines the molecular weight of the drug
• It controls only the color of the coacervates
• Stoichiometry is irrelevant in coacervation

Correct Answer: Correct charge balance maximizes attraction and coacervate yield

Q18. What role does core hydrophobicity play in coacervation microencapsulation?

• Hydrophobic cores better retain within hydrophobic regions of the coacervate, affecting encapsulation efficiency
• Hydrophobicity only affects drying rate
• Hydrophobic cores always prevent coacervation
• Core hydrophobicity controls pH of the system

Correct Answer: Hydrophobic cores better retain within hydrophobic regions of the coacervate, affecting encapsulation efficiency

Q19. Which is a common disadvantage of glutaraldehyde crosslinking?

• Potential toxicity residues and need for thorough removal or neutralization
• It creates completely water-soluble shells
• It prevents any controlled release
• It always reduces encapsulation efficiency to zero

Correct Answer: Potential toxicity residues and need for thorough removal or neutralization

Q20. What is the effect of polymer concentration on coacervate viscosity?

• Higher polymer concentration increases coacervate viscosity
• Polymer concentration decreases viscosity
• Viscosity is independent of polymer concentration
• Viscosity drops to zero at high polymer concentration

Correct Answer: Higher polymer concentration increases coacervate viscosity

Q21. Which release mechanism is common for drug from coacervate microcapsules?

• Diffusion through the polymer shell
• Instantaneous dissolution of wall in air
• Emission via radioactive decay
• Osmotic explosion due to vacuum

Correct Answer: Diffusion through the polymer shell

Q22. What is the binodal curve in a phase diagram related to coacervation?

• The boundary defining compositions where phase separation begins
• The line showing maximum viscosity only
• The temperature at which polymers evaporate
• The pressure where coacervates solidify

Correct Answer: The boundary defining compositions where phase separation begins

Q23. Which parameter improves coacervate droplet stability against coalescence?

• Crosslinking of the coacervate shell
• Increasing ionic strength drastically
• Raising temperature above polymer degradation
• Removing all water instantly

Correct Answer: Crosslinking of the coacervate shell

Q24. What is a primary application of coacervation in pharmaceuticals?

• Taste masking and stabilization of sensitive actives
• Increasing the melting point of tablets
• Creating metallic implants
• Sterilizing parenteral formulations

Correct Answer: Taste masking and stabilization of sensitive actives

Q25. Which parameter is adjusted to shift the isoelectric point of protein-based coacervates?

• pH of the medium
• Ambient humidity only
• Color of the solvent
• Magnetic field strength

Correct Answer: pH of the medium

Q26. In complex coacervation, what happens when you exceed optimal polymer ratio?

• Excess polymer may remain in solution and reduce coacervate yield
• Coacervate yield increases indefinitely
• The core material evaporates
• Crosslinking occurs spontaneously without agents

Correct Answer: Excess polymer may remain in solution and reduce coacervate yield

Q27. Which analytical method estimates particle size distribution of coacervate microcapsules?

• Laser diffraction or dynamic light scattering
• Infrared spectroscopy
• pH titration
• Colorimetry

Correct Answer: Laser diffraction or dynamic light scattering

Q28. What does higher coacervate yield indicate in formulation?

• Efficient phase separation and polymer deposition on cores
• Lower encapsulation efficiency always
• Complete degradation of polymer
• No interaction between polymer and core

Correct Answer: Efficient phase separation and polymer deposition on cores

Q29. Which wall property improves controlled release from microcapsules?

• Increased shell thickness and crosslink density
• Decreased molecular weight of core
• High porosity with no crosslinking
• Complete water solubility of wall

Correct Answer: Increased shell thickness and crosslink density

Q30. During encapsulation of volatile actives, what coacervation consideration is critical?

• Fast deposition and immediate crosslinking to minimize loss
• Long processing time to allow evaporation
• High processing temperature to accelerate release
• Avoiding any polymer in formulation

Correct Answer: Fast deposition and immediate crosslinking to minimize loss

Q31. What is the role of surfactants in coacervation emulsions?

• Stabilize core droplets and influence droplet size before coacervation
• Always prevent coacervate formation
• Act as crosslinkers for polymer shells
• Convert coacervates into gas bubbles

Correct Answer: Stabilize core droplets and influence droplet size before coacervation

Q32. Which observation indicates successful coacervate deposition around core particles?

• Opaque or milky appearance and visible droplets that coalesce around cores
• Complete transparency with no visible change
• Immediate clear solution after adding polymer
• Generation of ammonia gas

Correct Answer: Opaque or milky appearance and visible droplets that coalesce around cores

Q33. How does molecular weight of polymers affect coacervation?

• Higher molecular weight generally increases viscosity and affects coacervate strength and yield
• Molecular weight has no influence
• Lower molecular weight always gives stronger shells
• Only monomers can form coacervates

Correct Answer: Higher molecular weight generally increases viscosity and affects coacervate strength and yield

Q34. What is the significance of turbidity measurements in coacervation studies?

• They track phase separation and coacervate formation kinetics
• They measure crosslink density directly
• They determine drug potency
• They measure electrical conductivity only

Correct Answer: They track phase separation and coacervate formation kinetics

Q35. Which polymer pair would be suitable for coacervation at acidic pH?

• Positively charged chitosan with negatively charged alginate at pH below alginate pKa
• Neutral polyethylene glycol with polystyrene
• Two similarly charged anionic polymers
• Nonpolymeric salts only

Correct Answer: Positively charged chitosan with negatively charged alginate at pH below alginate pKa

Q36. How is release rate commonly modulated in coacervate microcapsules?

• By changing shell composition, thickness, and crosslinking density
• Only by altering core molecular weight
• By increasing ambient light intensity
• By adding metallic nanoparticles always

Correct Answer: By changing shell composition, thickness, and crosslinking density

Q37. What safety concern must be addressed when using aldehyde crosslinkers?

• Residual toxicity and need for quenching and thorough washing
• They always make capsules nonfunctional
• They convert drug to explosive compounds
• They are inert and require no handling precautions

Correct Answer: Residual toxicity and need for quenching and thorough washing

Q38. Which phenomenon causes coacervate droplets to merge into larger droplets?

• Coalescence due to low interfacial stabilization
• Polymer crystallization within droplets
• Complete ionic crosslinking preventing movement
• Instantaneous solidification of droplets

Correct Answer: Coalescence due to low interfacial stabilization

Q39. What is an advantage of using protein–polysaccharide coacervation?

• Biodegradable, biocompatible shells suitable for oral and topical dosage forms
• They are always inert to biological systems
• They prevent any drug release forever
• They are immune to pH changes

Correct Answer: Biodegradable, biocompatible shells suitable for oral and topical dosage forms

Q40. Which factor is NOT typically varied to optimize coacervation?

• Color of the reaction vessel
• Polymer concentration ratio
• pH of the medium
• Ionic strength and temperature

Correct Answer: Color of the reaction vessel

Q41. What does a high polydispersity index (PDI) indicate for microcapsule batches?

• Wide variation in particle sizes within the batch
• Perfect uniformity of particle size
• High drug potency only
• Complete absence of core material

Correct Answer: Wide variation in particle sizes within the batch

Q42. Which test evaluates mechanical strength of coacervate shells?

• Compression or rupture testing of single microcapsules
• pH titration only
• Color comparison with standards
• Thermal evaporation analysis

Correct Answer: Compression or rupture testing of single microcapsules

Q43. Why might one use genipin instead of glutaraldehyde?

• Genipin is a less toxic natural crosslinker offering biocompatible crosslinking
• Genipin always dissolves shells instantly
• Genipin is colorless and inert in all cases
• Genipin prevents any drug release permanently

Correct Answer: Genipin is a less toxic natural crosslinker offering biocompatible crosslinking

Q44. What is the likely effect of increasing salt concentration in a complex coacervation system?

• Screening of electrostatic interactions leading to reduced coacervate formation
• Enhanced electrostatic attraction and unlimited coacervation
• Immediate polymer degradation
• Creation of covalent bonds between polymers

Correct Answer: Screening of electrostatic interactions leading to reduced coacervate formation

Q45. Which component often acts as the core material in coacervation microencapsulation for oral dosage?

• Oils, flavors, or active pharmaceutical ingredients in liquid form
• Metal filings exclusively
• Inert gases only
• Glass beads only

Correct Answer: Oils, flavors, or active pharmaceutical ingredients in liquid form

Q46. How can environmental pH trigger drug release from coacervate capsules?

• pH changes alter polymer ionization and swelling, increasing permeability and release
• pH has no effect once capsule is formed
• pH only changes color, not release
• pH always causes immediate shell dissolution regardless of polymer

Correct Answer: pH changes alter polymer ionization and swelling, increasing permeability and release

Q47. Which rheological property is important during coacervate deposition?

• Viscosity of coacervate phase affecting coating uniformity
• Magnetic susceptibility of polymers
• Optical absorbance at 700 nm
• Boiling point of water

Correct Answer: Viscosity of coacervate phase affecting coating uniformity

Q48. What is “secondary coacervate” in some formulations?

• A subsequent deposition layer formed by repeating coacervation to increase shell thickness
• The gas evolved during drying
• The first droplet formed initially
• A type of permanent solid precipitate unrelated to coacervation

Correct Answer: A subsequent deposition layer formed by repeating coacervation to increase shell thickness

Q49. Which regulatory consideration is important for coacervate-encapsulated drugs?

• Residual crosslinker levels and release profile consistency for safety and efficacy
• Color matching with other brands only
• Patent status of the reaction vessel paint
• Ambient noise during manufacture

Correct Answer: Residual crosslinker levels and release profile consistency for safety and efficacy

Q50. What is an effective strategy to scale up coacervation for industrial production?

• Optimize mixing, temperature control, and continuous processing to maintain droplet size and shell properties
• Use random batch changes without monitoring
• Remove control of pH and ionic strength entirely
• Replace polymers with metals to speed up the process

Correct Answer: Optimize mixing, temperature control, and continuous processing to maintain droplet size and shell properties

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com