Targeted Delivery – Nanoparticles, Liposomes, Niosomes MCQs With Answer

This quiz collection focuses on targeted delivery systems using nanoparticles, liposomes, and niosomes, tailored for M.Pharm students studying Novel Drug Delivery Systems. It covers fundamentals and advanced concepts including passive and active targeting, formulation and preparation methods, surface modification (PEGylation, ligand conjugation), characterization techniques, stability and sterilization concerns, and delivery of small molecules and nucleic acids. Questions probe mechanistic understanding (EPR effect, bilayer phase behavior, critical packing parameters), practical formulation choices (cholesterol content, surfactant selection, cryoprotectants), and translational issues (scale-up, immunogenicity, regulatory-relevant attributes). Use these MCQs to test, revise, and deepen your conceptual and application-level knowledge.

Q1. What best describes the Enhanced Permeability and Retention (EPR) effect exploited by nanoparticle-based passive targeting?

• Active receptor-mediated endocytosis of ligand-decorated particles
• Increased tumor vascular permeability and poor lymphatic drainage that allow nanoparticles to accumulate
• Rapid renal clearance of nanoparticles smaller than 5 nm
• Charge-based adsorption of particles to cell membranes

Correct Answer: Increased tumor vascular permeability and poor lymphatic drainage that allow nanoparticles to accumulate

Q2. Which chemical coupling method is commonly used to covalently attach targeting ligands (e.g., peptides, antibodies) to liposome surface lipids bearing carboxyl groups?

• EDC/NHS carbodiimide-mediated amide bond formation
• Hydrophobic insertion via cholesterol anchoring only
• Electrostatic adsorption using sodium chloride
• Physical adsorption by simple incubation without chemistry

Correct Answer: EDC/NHS carbodiimide-mediated amide bond formation

Q3. The main purpose of PEGylating liposomes is to:

• Increase membrane rigidity to prevent drug release
• Enhance opsonization and rapid clearance by the mononuclear phagocyte system
• Provide a steric barrier that reduces protein adsorption and prolongs circulation time
• Promote aggregation to improve depot formation at the injection site

Correct Answer: Provide a steric barrier that reduces protein adsorption and prolongs circulation time

Q4. How does increasing cholesterol content typically affect a phospholipid bilayer in liposomes?

• It always increases membrane permeability to water-soluble drugs
• It decreases bilayer rigidity and lowers transition temperature
• It orders and stabilizes the bilayer, reducing permeability and preventing leakage
• It converts unilamellar vesicles into micelles

Correct Answer: It orders and stabilizes the bilayer, reducing permeability and preventing leakage

Q5. Which liposome preparation method commonly produces multilamellar vesicles by evaporating organic solvent to form a thin lipid film followed by hydration?

• Reverse-phase evaporation
• Thin film hydration (Bangham) method
• Ethanol injection method
• Microfluidic mixing

Correct Answer: Thin film hydration (Bangham) method

Q6. Reverse-phase evaporation method is particularly advantageous because it:

• Produces only large unilamellar vesicles with low aqueous core volume
• Generates liposomes without using any organic solvents
• Provides relatively high encapsulation efficiency for water-soluble drugs
• Is ideal for preparing niosomes from nonionic surfactants

Correct Answer: Provides relatively high encapsulation efficiency for water-soluble drugs

Q7. Which of the following is a major advantage of niosomes over conventional phospholipid liposomes?

• Niosomes are inherently more immunogenic than liposomes
• Niosomes require natural phospholipids and are less chemically stable
• Niosomes are prepared from nonionic surfactants and are often cheaper and more chemically stable
• Niosomes cannot entrap hydrophilic drugs in their core

Correct Answer: Niosomes are prepared from nonionic surfactants and are often cheaper and more chemically stable

Q8. Why is zeta potential measurement important for nanoparticle formulations?

• It directly measures the hydrodynamic diameter of particles
• It indicates surface charge which influences colloidal stability and interaction with biological components
• It quantifies encapsulation efficiency of hydrophobic drugs
• It determines the lipid bilayer phase transition temperature

Correct Answer: It indicates surface charge which influences colloidal stability and interaction with biological components

Q9. Dynamic Light Scattering (DLS) primarily provides which key characteristics of nanoparticle dispersions?

• Particle morphology and lamellarity
• Hydrodynamic size distribution and polydispersity index (PDI)
• Absolute particle mass and chemical composition
• Entrapment efficiency of the drug

Correct Answer: Hydrodynamic size distribution and polydispersity index (PDI)

Q10. Entrapment efficiency of a drug in liposomes is influenced by all of the following EXCEPT:

• Drug aqueous solubility and partition coefficient
• Lipid composition and bilayer fluidity
• Method of preparation and drug-to-lipid ratio
• Ambient room lighting during storage

Correct Answer: Ambient room lighting during storage

Q11. Cationic liposomes are commonly used for nucleic acid delivery because:

• They avoid any interaction with serum proteins in vivo
• Electrostatic complexation with negatively charged nucleic acids facilitates condensation and cellular uptake
• They are non-toxic and show no inflammatory responses
• They always provide long circulation half-life without PEGylation

Correct Answer: Electrostatic complexation with negatively charged nucleic acids facilitates condensation and cellular uptake

Q12. pH-sensitive liposomes trigger drug release in acidic environments; which lipid pair is classically used to confer pH sensitivity?

• DPPC and cholesterol
• DOPE (dioleoylphosphatidylethanolamine) and CHEMS (cholesteryl hemisuccinate)
• DSPC and PEG-DSPE
• SPC and Span 80

Correct Answer: DOPE (dioleoylphosphatidylethanolamine) and CHEMS (cholesteryl hemisuccinate)

Q13. Which particle size range is most likely to favor uptake by the mononuclear phagocyte system (MPS) in liver and spleen?

• Under 5 nm
• Approximately 10–50 nm
• Approximately 100–300 nm
• Greater than 1 µm

Correct Answer: Approximately 100–300 nm

Q14. The critical packing parameter (CPP = v / (a0 × l)) helps predict self-assembled morphology; a CPP greater than 1 typically favors formation of:

• Spherical micelles
• Cylindrical micelles
• Inverted (reverse) structures such as inverted hexagonal or inverted micelles
• Unilamellar vesicles (liposomes)

Correct Answer: Inverted (reverse) structures such as inverted hexagonal or inverted micelles

Q15. Which sterilization method is generally preferred for liposomal dispersions intended for parenteral use when particle size is below 220 nm?

• Autoclaving at 121°C for 15 minutes for all formulations
• Membrane filtration through a 0.22 µm sterile filter
• Gamma irradiation at high doses without formulation optimization
• Dry heat sterilization at 160°C

Correct Answer: Membrane filtration through a 0.22 µm sterile filter

Q16. During lyophilization (freeze-drying) of liposomes or niosomes, which excipient is commonly used as a cryoprotectant to preserve vesicle integrity?

• Sodium lauryl sulfate
• Trehalose or sucrose
• Cholesterol at high concentration only
• Ethanol as a cryoprotectant

Correct Answer: Trehalose or sucrose

Q17. The gel-to-liquid crystalline phase transition temperature (Tm) of phospholipids influences liposome behavior because:

• Liposomes with Tm above body temperature are more fluid in vivo and leak drug rapidly
• Lipids with higher Tm form more rigid bilayers at body temperature, reducing permeability and slowing release
• Tm only affects color and has no impact on drug release kinetics
• Lower Tm always increases circulation time in blood

Correct Answer: Lipids with higher Tm form more rigid bilayers at body temperature, reducing permeability and slowing release

Q18. In vesicular systems, hydrophilic drugs are primarily located in the:

• Lipid bilayer hydrophobic core
• Outer adsorbed corona only
• Aqueous core/internal aqueous compartments
• Bound covalently to cholesterol molecules

Correct Answer: Aqueous core/internal aqueous compartments

Q19. How does a strongly positive surface charge on nanoparticles generally affect in vivo biodistribution after intravenous administration?

• It typically prolongs circulation time and avoids RES uptake
• It favors rapid clearance from circulation and increased uptake by liver and spleen due to opsonization
• It prevents cellular uptake and endosomal escape
• It makes particles completely inert to immune recognition

Correct Answer: It favors rapid clearance from circulation and increased uptake by liver and spleen due to opsonization

Q20. Which advantage does microfluidic-based liposome or nanoparticle production offer when considering scale-up and reproducibility?

• It eliminates need for solvent removal steps but gives poor size control
• It provides precise mixing conditions, narrow size distributions, and scalable continuous manufacture
• It always avoids use of any organic solvents regardless of formulation
• It is only suitable for producing particles larger than 1 µm

Correct Answer: It provides precise mixing conditions, narrow size distributions, and scalable continuous manufacture

Download