Targeted drug delivery systems are designed to deliver therapeutic agents selectively to diseased sites while minimizing systemic exposure. For B.Pharm students, understanding core concepts and rationale — including site-specific delivery, controlled release, pharmacokinetics, biodistribution, and toxicity reduction — is essential. Key carriers such as nanoparticles, liposomes, micelles, dendrimers and antibody–drug conjugates employ passive (EPR) and active (ligand-mediated) targeting, PEGylation, and stimuli-responsive strategies to improve therapeutic index and bioavailability. Familiarity with design principles, characterization (size, zeta potential, encapsulation efficiency), and clinical translation challenges prepares students for pharmaceutical research and development. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What is the primary goal of targeted drug delivery systems?
- To increase drug solubility only
- To deliver drugs selectively to diseased sites while reducing systemic toxicity
- To make drugs more expensive
- To reduce drug potency
Correct Answer: To deliver drugs selectively to diseased sites while reducing systemic toxicity
Q2. Which rationale most directly explains why targeted delivery can improve therapy?
- By reducing manufacturing costs
- By increasing systemic drug exposure
- By increasing local drug concentration at the disease site and lowering off-target effects
- By eliminating the need for dosing schedules
Correct Answer: By increasing local drug concentration at the disease site and lowering off-target effects
Q3. The Enhanced Permeability and Retention (EPR) effect is an example of which targeting strategy?
- Active targeting using antibodies
- Passive targeting based on tumor vasculature
- Cell-specific endocytosis
- Transdermal diffusion
Correct Answer: Passive targeting based on tumor vasculature
Q4. Active targeting typically involves which of the following?
- Accumulation due to leaky vasculature
- Conjugation of ligands such as antibodies or peptides to carrier surfaces
- Increasing particle size to >1 µm
- Using only hydrophobic polymers
Correct Answer: Conjugation of ligands such as antibodies or peptides to carrier surfaces
Q5. Liposomes are best described as:
- Solid crystalline drug particles
- Spherical vesicles with one or more phospholipid bilayers encapsulating aqueous core
- Linear polymer chains
- Single-molecule surfactants
Correct Answer: Spherical vesicles with one or more phospholipid bilayers encapsulating aqueous core
Q6. PEGylation of nanoparticles is used primarily to:
- Increase particle aggregation
- Enhance opsonization and rapid clearance
- Create a hydrophilic stealth layer that reduces immune recognition and prolongs circulation
- Increase particle density for sedimentation
Correct Answer: Create a hydrophilic stealth layer that reduces immune recognition and prolongs circulation
Q7. How does nanoparticle size influence biodistribution?
- Size has no effect on biodistribution
- Smaller nanoparticles (<200 nm) typically show better tumor accumulation via EPR and longer circulation
- Only particles >5 µm circulate longest
- Very large nanoparticles avoid uptake by phagocytic cells
Correct Answer: Smaller nanoparticles (<200 nm) typically show better tumor accumulation via EPR and longer circulation
Q8. Which surface charge generally promotes cellular uptake but may increase toxicity?
- Neutral charge
- Highly negative charge
- Highly positive charge
- Zwitterionic charge only
Correct Answer: Highly positive charge
Q9. The reticuloendothelial system (RES) primarily affects nanoparticles by:
- Enhancing nanoparticle targeting to tumors
- Promoting opsonization and clearance by macrophages in liver and spleen
- Preventing degradation of polymers
- Transporting nanoparticles across the blood–brain barrier
Correct Answer: Promoting opsonization and clearance by macrophages in liver and spleen
Q10. An antibody–drug conjugate (ADC) contains which core components?
- Nanoparticle core and surfactant only
- Antibody, cytotoxic drug, and a chemical linker
- Polymer backbone and sugar moieties only
- Free drug and non-specific protein
Correct Answer: Antibody, cytotoxic drug, and a chemical linker
Q11. Controlled drug release from a matrix system typically follows which mechanisms?
- Diffusion, degradation/erosion, or swelling-controlled release
- Only enzymatic cleavage
- Only direct absorption through skin
- Immediate disintegration without control
Correct Answer: Diffusion, degradation/erosion, or swelling-controlled release
Q12. pH-sensitive drug carriers are best suited for targeting which environments?
- Neutral blood plasma only
- Acidic tumor microenvironment or endo/lysosomal compartments
- Alkaline urine exclusively
- Dry skin surface
Correct Answer: Acidic tumor microenvironment or endo/lysosomal compartments
Q13. A prodrug approach in targeted delivery means:
- The drug is administered as its active form always
- The drug is chemically modified to an inactive or less active form that converts to active drug at the target site
- Drug is only mixed with excipients
- Eliminating the need for clinical trials
Correct Answer: The drug is chemically modified to an inactive or less active form that converts to active drug at the target site
Q14. Thermo-responsive polymers change properties in response to:
- Light wavelength only
- Temperature, undergoing phase transition near a critical temperature
- Magnetic fields exclusively
- pH but not temperature
Correct Answer: Temperature, undergoing phase transition near a critical temperature
Q15. Common targeting ligands used for tumor targeting include:
- Folate, transferrin, peptides, and antibodies
- Sodium chloride only
- Random polymers without specificity
- Sugars that never bind receptors
Correct Answer: Folate, transferrin, peptides, and antibodies
Q16. Dendrimers are characterized by:
- Linear, non-branched polymer chains
- Highly branched, monodisperse tree-like macromolecules with terminal functional groups
- Only lipid bilayer structures
- Metallic crystalline cores exclusively
Correct Answer: Highly branched, monodisperse tree-like macromolecules with terminal functional groups
Q17. Polymeric micelles are particularly useful for delivering:
- Hydrophilic drugs only
- Hydrophobic drugs solubilized in the micelle core
- Gas molecules exclusively
- Large proteins without modification
Correct Answer: Hydrophobic drugs solubilized in the micelle core
Q18. Which is a clinically approved liposomal anticancer formulation?
- Insulin liposomal suspension
- Doxil (liposomal doxorubicin)
- Aspirin liposomal gel
- Unencapsulated tetracycline
Correct Answer: Doxil (liposomal doxorubicin)
Q19. A burst release in nanoparticle formulations refers to:
- Gradual release over months only
- Rapid initial release of a large fraction of drug soon after administration
- No release of drug at all
- Release triggered solely by light
Correct Answer: Rapid initial release of a large fraction of drug soon after administration
Q20. Zero-order release kinetics implies:
- Drug release rate decreases exponentially over time
- A constant drug release rate independent of drug concentration
- Immediate release of entire dose
- Release only after complete polymer degradation
Correct Answer: A constant drug release rate independent of drug concentration
Q21. Which technique is commonly used to study nanoparticle biodistribution in vivo?
- Radiolabeling and imaging (e.g., PET, SPECT, fluorescence imaging)
- Only electron microscopy on frozen tissue without labeling
- pH paper strips in blood
- Gas chromatography of whole tissues without extraction
Correct Answer: Radiolabeling and imaging (e.g., PET, SPECT, fluorescence imaging)
Q22. Formation of a protein corona around nanoparticles typically results in:
- Complete invisibility to immune cells
- Altered biodistribution, recognition by phagocytes, and possible loss of targeting ligand function
- Instant dissolution of the nanoparticle
- Transformation into a liposome
Correct Answer: Altered biodistribution, recognition by phagocytes, and possible loss of targeting ligand function
Q23. Targeted delivery can increase the therapeutic index by:
- Reducing biological activity of the drug
- Raising effective dose systemically
- Enhancing efficacy at the target while reducing systemic side effects
- Preventing metabolism entirely
Correct Answer: Enhancing efficacy at the target while reducing systemic side effects
Q24. Which barrier is most critical to address for brain-targeted drug delivery?
- Gastrointestinal mucosa
- Blood–brain barrier (BBB)
- Skin stratum corneum only
- Lymphatic drainage of limbs
Correct Answer: Blood–brain barrier (BBB)
Q25. Common administration routes used for targeted delivery include:
- Intravenous, inhalation, topical, and oral routes depending on target site
- Only sublingual route for all targets
- Only intramuscular injections regardless of disease
- Ingesting raw nanoparticles without formulation
Correct Answer: Intravenous, inhalation, topical, and oral routes depending on target site
Q26. Receptor-mediated transcytosis across the BBB commonly exploits which receptors?
- Albumin receptors only
- Transferrin and insulin receptors
- Hair follicle receptors
- Gastric proton pumps
Correct Answer: Transferrin and insulin receptors
Q27. Which sterilization method is often suitable for nanoparticle dispersions without damaging polymer carriers?
- Autoclaving at high temperature for long durations always
- Sterile filtration through 0.22 µm filters for appropriately sized particles
- Exposing to strong acids
- Microwave irradiation of closed vials
Correct Answer: Sterile filtration through 0.22 µm filters for appropriately sized particles
Q28. Complement activation-related pseudoallergy (CARPA) is a safety concern that arises due to:
- Excessive oral absorption
- Immune activation by certain nanoparticle surfaces causing hypersensitivity reactions
- Purely mechanical blockage of capillaries
- Only degradation into inert products
Correct Answer: Immune activation by certain nanoparticle surfaces causing hypersensitivity reactions
Q29. Major regulatory challenges in translating targeted delivery systems include:
- Characterization, reproducibility, safety profiling, and complex manufacturing scale-up
- Only choosing a color for packaging
- Never needing clinical data
- Excluding stability studies entirely
Correct Answer: Characterization, reproducibility, safety profiling, and complex manufacturing scale-up
Q30. Which characterization parameters are essential for nanoparticle formulations?
- Particle size, size distribution (PDI), zeta potential, encapsulation efficiency, and release profile
- Only packaging label design
- Color of the formulation alone
- Only the brand name
Correct Answer: Particle size, size distribution (PDI), zeta potential, encapsulation efficiency, and release profile
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