Applications of targeted systems in therapy focus on delivering drugs precisely to diseased cells or tissues to improve efficacy and reduce side effects. For B.Pharm students, understanding targeted drug delivery—including targeted systems such as nanoparticles, liposomes, antibody‑drug conjugates (ADCs), polymeric micelles and stimuli‑responsive carriers—is essential. Key concepts include passive and active targeting, receptor‑mediated endocytosis, blood‑brain barrier (BBB) strategies, controlled release, pharmacokinetics, and safety challenges like immunogenicity and RES clearance. Clinical examples (Doxil, Abraxane, T‑DM1) and analytical methods (DLS, TEM, zeta potential) illustrate translation from formulation to therapy. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What is the primary goal of targeted drug delivery systems in therapy?
- To increase nonspecific systemic drug distribution
- To direct drugs specifically to diseased cells or tissues to improve efficacy and reduce toxicity
- To speed up drug metabolism in the liver
- To eliminate the need for controlled release
Correct Answer: To direct drugs specifically to diseased cells or tissues to improve efficacy and reduce toxicity
Q2. Which mechanism best describes passive targeting of nanoparticles to solid tumors?
- Receptor‑ligand binding on tumor cells
- Enhanced permeability and retention (EPR) effect due to leaky tumor vasculature
- Active transport across the BBB by transferrin receptors
- Enzyme‑triggered prodrug activation
Correct Answer: Enhanced permeability and retention (EPR) effect due to leaky tumor vasculature
Q3. Which of the following is an example of an active targeting ligand used in targeted systems?
- Polyethylene glycol (PEG)
- Folate (folic acid)
- Phosphate buffer
- Sodium chloride
Correct Answer: Folate (folic acid)
Q4. Which clinical formulation is a PEGylated liposomal anticancer product demonstrating targeted delivery advantages?
- Abraxane (albumin‑bound paclitaxel)
- Doxil (PEGylated liposomal doxorubicin)
- Humira (adalimumab)
- Metformin extended‑release
Correct Answer: Doxil (PEGylated liposomal doxorubicin)
Q5. In antibody‑drug conjugates (ADCs), which component links the cytotoxic payload to the targeting antibody?
- Excipient
- Linker
- Surfactant
- Co‑solvent
Correct Answer: Linker
Q6. Which linker type is commonly cleaved inside lysosomes by acidic pH or proteases to release payload in ADCs?
- Non‑cleavable linker
- Covalent irreversible crosslinker
- Cleavable (acid‑sensitive or protease‑sensitive) linker
- PEGylation linker
Correct Answer: Cleavable (acid‑sensitive or protease‑sensitive) linker
Q7. What advantage does PEGylation impart to nanoparticle drug carriers?
- Increases opsonization and rapid RES clearance
- Improves steric stabilization, reduces protein adsorption, and prolongs circulation time
- Enhances immediate cellular uptake by macrophages
- Removes need for targeting ligands
Correct Answer: Improves steric stabilization, reduces protein adsorption, and prolongs circulation time
Q8. Which size range of nanoparticles is generally considered optimal for enhanced tumor accumulation via the EPR effect?
- 1–5 nm
- 10–200 nm
- 500–1000 nm
- Over 5 micrometers
Correct Answer: 10–200 nm
Q9. Which analytical technique is commonly used to determine particle size distribution of nanocarriers?
- Dynamic light scattering (DLS)
- High‑performance liquid chromatography (HPLC) only
- UV spectroscopy without calibration
- Gas chromatography
Correct Answer: Dynamic light scattering (DLS)
Q10. Zeta potential measurement primarily provides information about which property of colloidal drug carriers?
- Hydrophobic drug loading capacity
- Surface charge and colloidal stability
- Chemical structure of the polymer backbone
- Thermal degradation point
Correct Answer: Surface charge and colloidal stability
Q11. Which endocytic pathway is often exploited by targeted ligands (e.g., transferrin) to enter cells?
- Clathrin‑mediated endocytosis
- Passive diffusion through lipid bilayer
- Paracellular transport
- Desmosomal junction transport
Correct Answer: Clathrin‑mediated endocytosis
Q12. For delivering therapeutics across the blood‑brain barrier (BBB), which strategy is frequently employed?
- Exploiting receptor‑mediated transcytosis using transferrin or insulin receptors
- Increasing systemic dose without targeting
- Using large (>1 µm) particulate carriers
- Avoiding any ligand modification
Correct Answer: Exploiting receptor‑mediated transcytosis using transferrin or insulin receptors
Q13. Which disease area has seen major applications of targeted drug delivery, especially with nanoparticles and ADCs?
- Oncology (cancer therapy)
- Common cold symptomatic relief
- Vitamin deficiency prevention
- Fracture immobilization
Correct Answer: Oncology (cancer therapy)
Q14. What is the main therapeutic advantage of increasing a drug’s therapeutic index through targeted systems?
- Widening safety margin by increasing efficacy and reducing off‑target toxicity
- International patent extension
- Shortening half‑life to reduce dosing intervals
- Ensuring immediate systemic exposure
Correct Answer: Widening safety margin by increasing efficacy and reducing off‑target toxicity
Q15. Which targeting moiety is nucleic‑acid based and can bind specific proteins or cellular receptors with high affinity?
- Aptamer
- Albumin
- Sodium alginate
- Cellulose
Correct Answer: Aptamer
Q16. Which payload type is commonly delivered by siRNA‑loaded targeted nanoparticles?
- Small interfering RNA to silence gene expression
- Nonselective antiseptics
- Large bacterial proteins for vaccination only
- Inert dyes with no therapeutic effect
Correct Answer: Small interfering RNA to silence gene expression
Q17. In designing ligand‑targeted carriers, why is ligand density important?
- Only affects color of formulation
- Higher density always ensures better targeting regardless of other factors
- Optimal density balances receptor engagement and avoids steric hindrance or immune recognition
- Density has no impact on cellular uptake
Correct Answer: Optimal density balances receptor engagement and avoids steric hindrance or immune recognition
Q18. Which stimulus is commonly exploited by pH‑responsive drug delivery systems in tumor microenvironments?
- Neutral physiological pH 7.4 only
- Relatively acidic pH in tumors and endosomes
- High oxygen concentrations in tumors
- Magnetic field of the Earth
Correct Answer: Relatively acidic pH in tumors and endosomes
Q19. Which in vitro technique helps visualize nanoparticle morphology and core structure at high resolution?
- Transmission electron microscopy (TEM)
- Colorimetric pH strips
- Viscometry only
- Macroscopic photography
Correct Answer: Transmission electron microscopy (TEM)
Q20. Which pharmacokinetic change is often observed with targeted nanoparticle carriers compared to free drug?
- Decreased circulation half‑life always
- Altered biodistribution with prolonged circulation and reduced volume of distribution for some carriers
- Complete elimination of hepatic metabolism
- Instant renal excretion unchanged by carrier
Correct Answer: Altered biodistribution with prolonged circulation and reduced volume of distribution for some carriers
Q21. Which targeting approach specifically uses overexpressed receptors on cancer cells to achieve selective delivery?
- Active targeting using receptor‑specific ligands
- Purely passive diffusion across membranes
- Systemic high‑dose chemotherapy without targeting
- Random covalent binding to plasma proteins
Correct Answer: Active targeting using receptor‑specific ligands
Q22. Which is a key challenge for targeted systems that must be addressed during formulation and clinical translation?
- Scale‑up manufacturing, stability, immunogenicity, and reproducibility
- Having too few excipients for taste masking only
- Eliminating all possible release from carrier
- Guaranteeing 100% receptor occupancy for every cell
Correct Answer: Scale‑up manufacturing, stability, immunogenicity, and reproducibility
Q23. Which metric is used to quantify drug release kinetics and can indicate diffusion‑controlled release from matrix systems?
- Higuchi model describing square‑root‑time dependence
- Beer’s constant only
- pKa of the drug exclusively
- Melting point measurement
Correct Answer: Higuchi model describing square‑root‑time dependence
Q24. Which targeting ligand is commonly used for cancer cells that overexpress folate receptors?
- Folate (folic acid) conjugation
- Heparin sulfate only
- Glucose without modification
- Polyvinyl alcohol coating
Correct Answer: Folate (folic acid) conjugation
Q25. Which statement best describes theranostics in the context of targeted systems?
- Combining therapy and diagnostic imaging in a single targeted platform to enable personalized treatment
- Only used for non‑biological sensors
- Strictly for oral dosage forms without targeting
- Refers solely to physical therapy methods
Correct Answer: Combining therapy and diagnostic imaging in a single targeted platform to enable personalized treatment
Q26. Which surface modification reduces recognition by the mononuclear phagocyte system (MPS) and prolongs nanoparticle circulation?
- Hydrophobic surfactant coating
- PEGylation or other hydrophilic stealth coatings
- Uncoated bare metal surface
- Large immunogenic protein opsonization
Correct Answer: PEGylation or other hydrophilic stealth coatings
Q27. Which clinical ADC targets HER2‑positive breast cancer and is an example of targeted therapy translation?
- Insulin glargine
- Trastuzumab emtansine (T‑DM1)
- Simvastatin
- Ibuprofen lysine
Correct Answer: Trastuzumab emtansine (T‑DM1)
Q28. What role do biodegradable polymers (e.g., PLGA) play in targeted delivery systems?
- Serve as nondegradable permanent implants only
- Provide controlled drug release and degrade into biocompatible byproducts
- Increase systemic toxicity by accumulating indefinitely
- Prevent any drug release under physiological conditions
Correct Answer: Provide controlled drug release and degrade into biocompatible byproducts
Q29. Which conjugation chemistry is commonly used for attaching ligands or drugs to carrier surfaces due to specificity and mild conditions?
- Click chemistry (e.g., azide‑alkyne cycloaddition)
- High‑temperature radical polymerization in bulk
- Combustion synthesis
- Strong acid hydrolysis of backbone only
Correct Answer: Click chemistry (e.g., azide‑alkyne cycloaddition)
Q30. Which preclinical study is essential to evaluate targeted system biodistribution and organ accumulation in vivo?
- Radiolabeling or fluorescent imaging‑based biodistribution studies in animal models
- Only in vitro dissolution in water at room temperature
- Human trials without prior animal data
- Measuring tablet hardness alone
Correct Answer: Radiolabeling or fluorescent imaging‑based biodistribution studies in animal models
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.
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