Advantages and disadvantages of microencapsulation MCQs With Answer

Advantages and disadvantages of microencapsulation MCQs With Answer

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Introduction

Microencapsulation is a vital technique in pharmaceutical technology that entraps active drug molecules within protective polymeric or lipidic shells to improve stability, control release, mask taste, and enable targeted delivery. B. Pharm students should understand common encapsulation techniques (spray drying, coacervation, solvent evaporation, liposomes), core and coating materials (PLGA, alginate, chitosan, gelatin), and key performance metrics like encapsulation efficiency, particle size, release kinetics, and stability. While offering advantages such as controlled release and improved bioavailability, microencapsulation also poses challenges including scale-up, residual solvents, burst release, and regulatory considerations. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the typical size range generally considered for microcapsules in pharmaceutical microencapsulation?

  • 1–100 nm
  • 1–1000 nm
  • 1–100 μm
  • 1–10 mm

Correct Answer: 1–100 μm

Q2. Which microencapsulation technique is most commonly used for heat-sensitive drugs because it operates at relatively low temperatures?

  • Spray drying
  • Spray congealing
  • Coacervation (phase separation)
  • Thermal melt extrusion

Correct Answer: Coacervation (phase separation)

Q3. Which polymer is biodegradable and frequently used for controlled release microcapsules in parenteral formulations?

  • Polyvinyl alcohol (PVA)
  • Polyethylene glycol (PEG)
  • Poly(lactic-co-glycolic acid) (PLGA)
  • Polyacrylate (Eudragit)

Correct Answer: Poly(lactic-co-glycolic acid) (PLGA)

Q4. Encapsulation efficiency (EE%) is best defined as:

  • The ratio of free drug to polymer weight
  • The percentage of initial drug successfully entrapped within microcapsules
  • The percentage of polymer coating on the particle surface
  • The particle size distribution width

Correct Answer: The percentage of initial drug successfully entrapped within microcapsules

Q5. Which release mechanism is characterized by drug movement through polymer pores or matrix without significant polymer degradation?

  • Diffusion-controlled release
  • Erosion-controlled release
  • Osmotic pump release
  • Enzymatic cleavage release

Correct Answer: Diffusion-controlled release

Q6. A major advantage of microencapsulation for oral peptide drugs is:

  • Increased enzymatic degradation in the GI tract
  • Taste masking only
  • Protection against acidic degradation and improved intestinal absorption
  • Guaranteed zero-order release without formulation work

Correct Answer: Protection against acidic degradation and improved intestinal absorption

Q7. Which technique commonly uses an oil-in-water emulsion followed by solvent evaporation to form polymeric microcapsules?

  • Coacervation
  • Emulsion-solvent evaporation
  • Spray drying without solvent
  • Fluid-bed coating of pellets

Correct Answer: Emulsion-solvent evaporation

Q8. Which characterization method provides surface morphology and size visualization of microcapsules?

  • High-performance liquid chromatography (HPLC)
  • Scanning electron microscopy (SEM)
  • UV–visible spectrophotometry
  • Gel permeation chromatography (GPC)

Correct Answer: Scanning electron microscopy (SEM)

Q9. A common disadvantage of solvent-based microencapsulation methods is:

  • Complete absence of residual solvent
  • Low encapsulation of hydrophobic drugs
  • Potential residual organic solvents and regulatory concerns
  • Inability to form uniform particles

Correct Answer: Potential residual organic solvents and regulatory concerns

Q10. Which polymer is widely used for enteric coating microcapsules to prevent drug release in the stomach?

  • Gelatin
  • Alginate
  • Eudragit L or S (methacrylic acid copolymers)
  • Chitosan

Correct Answer: Eudragit L or S (methacrylic acid copolymers)

Q11. Burst release from microcapsules is mainly caused by:

  • Complete absence of drug on the particle surface
  • High drug loading and presence of surface-associated drug
  • Very thick, impermeable coatings
  • Use of purely hydrophobic cores only

Correct Answer: High drug loading and presence of surface-associated drug

Q12. Which cross-linking agent is often used with gelatin or alginate microcapsules to improve structural stability?

  • Calcium ions (Ca2+)
  • Sodium chloride (NaCl)
  • Polyethylene glycol (PEG)
  • Acetic acid

Correct Answer: Calcium ions (Ca2+)

Q13. Which in vitro test best assesses the release kinetics of a microencapsulated oral formulation?

  • Disintegration test only
  • Dissolution/release study under sink conditions
  • Moisture sorption analysis only
  • Colorimetric pH indicator strip test

Correct Answer: Dissolution/release study under sink conditions

Q14. Liposomal encapsulation primarily differs from polymeric microencapsulation by:

  • Using lipid bilayers to entrap drugs rather than solid polymer matrices
  • Always producing particles larger than 1 mm
  • Being unsuitable for hydrophobic drugs
  • Requiring higher temperatures for formation

Correct Answer: Using lipid bilayers to entrap drugs rather than solid polymer matrices

Q15. A key factor affecting drug release rate from polymeric microcapsules is:

  • Color of the polymer
  • Polymer molecular weight and hydrophobicity
  • Ambient light intensity
  • Tablet hardness only

Correct Answer: Polymer molecular weight and hydrophobicity

Q16. The Higuchi model describes drug release primarily controlled by:

  • Zero-order constant-rate mechanisms
  • Diffusion from a homogeneous matrix proportional to square root of time
  • Purely erosion-controlled mechanisms
  • First-order exponential decay kinetics

Correct Answer: Diffusion from a homogeneous matrix proportional to square root of time

Q17. Which coating approach is most suitable for coating small particles or pellets uniformly in industry scale?

  • Vortex mixing in a beaker
  • Fluid-bed coating
  • Manual dip coating one particle at a time
  • Static oven curing without spraying

Correct Answer: Fluid-bed coating

Q18. Microencapsulation can improve the stability of oxidizable drugs by:

  • Exposing drug directly to oxygen
  • Providing a barrier against moisture and oxygen
  • Increasing surface area for oxidation
  • Removing protective coatings

Correct Answer: Providing a barrier against moisture and oxygen

Q19. In spray drying microencapsulation, which parameter significantly impacts particle size and morphology?

  • Inlet air temperature and feed concentration
  • Magnetic field strength
  • Ambient atmospheric pressure only
  • Color of the feed solution

Correct Answer: Inlet air temperature and feed concentration

Q20. Which analytical technique is useful to confirm chemical interactions between drug and polymer in a microcapsule?

  • X-ray powder diffraction (XRPD) only for particle count
  • Fourier-transform infrared spectroscopy (FTIR)
  • Optical microscopy without spectra
  • Simple pH paper test

Correct Answer: Fourier-transform infrared spectroscopy (FTIR)

Q21. For probiotic microencapsulation intended for oral delivery, a primary objective is to:

  • Expose microorganisms to gastric acid
  • Maintain viability through GI transit and release in intestine
  • Convert live cells to lysed proteins
  • Encourage immediate release in stomach

Correct Answer: Maintain viability through GI transit and release in intestine

Q22. Which disadvantage is particularly relevant when encapsulating proteins and peptides?

  • Proteins always become more stable during encapsulation
  • Denaturation or loss of bioactivity due to processing conditions
  • No need for sterile processing
  • Encapsulation eliminates immunogenicity completely

Correct Answer: Denaturation or loss of bioactivity due to processing conditions

Q23. Osmotic-controlled release microcapsules typically rely on which principle?

  • Polymer crystallization only
  • Water influx creating osmotic pressure to push drug out through an orifice
  • Immediate dissolution of coating in all pH
  • Magnetic field-triggered release

Correct Answer: Water influx creating osmotic pressure to push drug out through an orifice

Q24. Which property of the core-to-coating ratio most directly affects the release rate?

  • Higher coating thickness generally slows release
  • Lower coating thickness always slows release
  • Core color dictates release rate
  • Coating ratio has no effect on release

Correct Answer: Higher coating thickness generally slows release

Q25. Interfacial polymerization is best described as:

  • Polymer formation at the interface of two immiscible phases creating a shell
  • Heating polymer until it melts into a core
  • Lyophilizing drugs without polymer
  • Dissolving polymer and drug in a single-phase solvent only

Correct Answer: Polymer formation at the interface of two immiscible phases creating a shell

Q26. Which stability concern is most critical for microencapsulated steroid drugs stored long-term?

  • Loss of color only
  • Chemical degradation such as oxidation or hydrolysis
  • Immediate microbial growth at room temperature regardless of water activity
  • Increase in magnetic susceptibility

Correct Answer: Chemical degradation such as oxidation or hydrolysis

Q27. Which factor increases the risk of aggregation and poor flow of microcapsule powders?

  • Low moisture content and spherical particles
  • High surface stickiness and electrostatic interactions
  • Perfect particle uniformity
  • Using only inorganic coatings

Correct Answer: High surface stickiness and electrostatic interactions

Q28. A key regulatory concern for injectable microencapsulated formulations is:

  • Absence of particle size control
  • Sterility assurance and particulate safety
  • Only taste masking requirements
  • Inevitability of high residual solvent levels

Correct Answer: Sterility assurance and particulate safety

Q29. Which mathematical kinetic model describes a constant amount of drug released per unit time?

  • First-order kinetics
  • Zero-order kinetics
  • Higuchi square-root model
  • Weibull model only

Correct Answer: Zero-order kinetics

Q30. To reduce burst release and improve sustained delivery, formulators often:

  • Increase drug loading on the particle surface
  • Use polymer blends, increase coating thickness, or add diffusion barriers
  • Switch to highly soluble coatings only
  • Avoid cross-linking or any stabilizing steps

Correct Answer: Use polymer blends, increase coating thickness, or add diffusion barriers

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