Polymers for NDDS MCQs With Answer

Polymers for NDDS MCQs With Answer

Polymers are central to designing Novel Drug Delivery Systems (NDDS), enabling controlled release, targeted delivery, and improved stability of therapeutics. This set of multiple-choice questions is designed for M.Pharm students to deepen understanding of polymer types, properties, mechanisms governing drug release, and practical considerations in formulation and regulatory contexts. Questions cover biodegradable and non-biodegradable polymers, natural and synthetic materials, polymer characterization (molecular weight, Tg), surface modification (PEGylation, ligand attachment), stimuli-responsive systems, and polymer processing methods relevant to NDDS. Use these MCQs to test core concepts, apply critical thinking to formulation choices, and prepare for examinations and research in advanced drug delivery.

Q1. Which property of PLGA primarily governs its bulk erosion behavior and consequently the drug release profile in NDDS?

• Lactic to glycolic acid ratio
• Glass transition temperature
• Polymer crystallinity
• Surface charge

Correct Answer: Lactic to glycolic acid ratio

Q2. In design of mucoadhesive drug delivery systems, which polymer characteristic most directly enhances adhesive interactions with mucosal surfaces?

• High hydrophobicity
• Abundant hydrogen bonding groups (e.g., hydroxyl, carboxyl, amine)
• High degree of crystallinity
• Low molecular weight

Correct Answer: Abundant hydrogen bonding groups (e.g., hydroxyl, carboxyl, amine)

Q3. PEGylation of therapeutic proteins and nanoparticles is primarily used to achieve which of the following outcomes?

• Increase particle aggregation in plasma
• Reduce immunogenicity and extend systemic circulation time
• Enhance rapid renal clearance
• Promote immediate cellular uptake by phagocytes

Correct Answer: Reduce immunogenicity and extend systemic circulation time

Q4. Which natural polymer is most commonly used for forming ionically crosslinked hydrogel beads for controlled release of proteins under mild conditions?

• Poly(lactic-co-glycolic acid) (PLGA)
• Alginate
• Polyvinyl alcohol (PVA)
• Polystyrene

Correct Answer: Alginate

Q5. For a polymer intended for sustained release via diffusion-controlled mechanism, which factor is least likely to slow drug release?

• Increased polymer hydrophobicity
• Lower polymer porosity
• Higher drug solubility in surrounding medium
• Higher polymer molecular weight

Correct Answer: Higher drug solubility in surrounding medium

Q6. Which statement accurately describes bulk erosion versus surface erosion in biodegradable polymers used in NDDS?

• Bulk erosion occurs when water penetration is slower than polymer degradation, leading to surface mass loss only
• Surface erosion preserves internal structure while surface layers degrade faster than water penetrates
• Bulk erosion results from enzymatic attack only and never from hydrolysis
• Surface erosion always gives zero-order drug release irrespective of geometry

Correct Answer: Surface erosion preserves internal structure while surface layers degrade faster than water penetrates

Q7. Chitosan is widely used in NDDS for mucoadhesion and permeation enhancement. Which molecular feature of chitosan is primarily responsible for its mucoadhesive behavior?

• Presence of quaternary ammonium groups
• Primary amine groups that are protonated under acidic conditions
• High degree of hydrophobic alkyl chains
• Crosslinked ether linkages

Correct Answer: Primary amine groups that are protonated under acidic conditions

Q8. Which polymer is a triblock copolymer used as a thermoresponsive injectable hydrogel that gels at body temperature?

• Poly(lactic acid) (PLA)
• Poloxamer (Pluronic) [PEO-PPO-PEO]
• Polyethyleneimine (PEI)
• Polyacrylic acid

Correct Answer: Poloxamer (Pluronic) [PEO-PPO-PEO]

Q9. When designing polymeric nanoparticles for targeted cancer therapy, which surface modification most directly enables active targeting to cells expressing a specific receptor?

• PEGylation to increase hydrophilicity
• Attachment of a ligand or antibody specific to the receptor
• Increasing particle size above 500 nm
• Incorporation of non-targeted anionic surfactant

Correct Answer: Attachment of a ligand or antibody specific to the receptor

Q10. Which polymer property correlates most strongly with the rate of hydrolytic degradation for linear aliphatic polyesters used in NDDS?

• Polymer color
• Hydrophobicity and crystallinity
• Presence of aromatic rings in backbone
• Surface charge at neutral pH

Correct Answer: Hydrophobicity and crystallinity

Q11. Dendrimers are highly branched polymers used in NDDS. Which advantage is characteristic of dendrimers compared to linear polymers?

• Undefined molecular weight distribution
• High monodispersity and multiple terminal functional groups for conjugation
• Inability to encapsulate hydrophobic drugs
• Rapid uncontrolled biodegradation in vivo

Correct Answer: High monodispersity and multiple terminal functional groups for conjugation

Q12. Cyclodextrins improve solubility of poorly soluble drugs primarily by which mechanism?

• Covalent bonding with drug molecules
• Formation of inclusion complexes with the hydrophobic portion of drug molecules
• Increasing bulk crystallinity of the drug
• Crosslinking drugs into a polymer matrix

Correct Answer: Formation of inclusion complexes with the hydrophobic portion of drug molecules

Q13. Which sterilization method is generally most damaging to biodegradable polymeric matrices containing sensitive proteins?

• Gamma irradiation at high doses
• Sterile filtration for nanoparticle suspensions
• Aseptic processing with sterile components
• Low-temperature ethylene oxide under controlled conditions

Correct Answer: Gamma irradiation at high doses

Q14. In polymer–drug conjugates, what is the primary role of a cleavable linker?

• To permanently bind the drug to polymer preventing release
• To enable controlled release of the drug in response to a biological stimulus or environment
• To increase polymer crystallinity
• To make the conjugate insoluble in biological fluids

Correct Answer: To enable controlled release of the drug in response to a biological stimulus or environment

Q15. Which polymer processing method is most suitable for producing uniform PLGA microspheres encapsulating protein drugs with minimal denaturation?

• High-temperature melt extrusion
• Water-in-oil-in-water (w/o/w) double emulsion solvent evaporation under controlled, low-shear conditions
• Direct compression
• Spray-drying at high inlet temperatures without protectants

Correct Answer: Water-in-oil-in-water (w/o/w) double emulsion solvent evaporation under controlled, low-shear conditions

Q16. Which measurement is most informative for predicting the mechanical behavior and flexibility of a polymeric implant at physiological temperature?

• Intrinsic viscosity in unrelated solvent
• Glass transition temperature (Tg)
• Colorimetric absorbance
• Surface roughness only

Correct Answer: Glass transition temperature (Tg)

Q17. Which class of polymers is commonly used as stabilizers/surfactants to prevent aggregation of nanoparticles during formulation and in biological fluids?

• Hydrophobic polystyrenes without amphiphilic character
• Amphiphilic block copolymers such as PEG-based surfactants
• Crosslinked rigid ceramics
• Unmodified crystalline sugars

Correct Answer: Amphiphilic block copolymers such as PEG-based surfactants

Q18. Stimuli-responsive polymers can release drugs in response to specific triggers. Which polymer property would you tailor to create a pH-responsive delivery system for tumor targeting?

• Introduce pH-sensitive ionizable groups (e.g., tertiary amines or carboxyls) with pKa near the target environment
• Increase thermal conductivity
• Maximize crystallinity to prevent swelling
• Remove all ionizable groups to maintain neutrality

Correct Answer: Introduce pH-sensitive ionizable groups (e.g., tertiary amines or carboxyls) with pKa near the target environment

Q19. Which regulatory consideration is most critical when selecting a polymer for injectable NDDS intended for clinical use?

• Polymer must be colored for brand recognition
• Established biocompatibility, degradation products safety, and prior regulatory approvals or history of safe use
• Polymer must be synthetically complex to increase IP protection regardless of safety data
• Polymer should have extremely high molecular weight without characterization

Correct Answer: Established biocompatibility, degradation products safety, and prior regulatory approvals or history of safe use

Q20. Which analytical technique is most appropriate to determine the molecular weight distribution and polydispersity of synthetic polymers used in NDDS?

• Differential scanning calorimetry (DSC)
• Gel permeation chromatography (size exclusion chromatography)
• UV-visible spectroscopy at single wavelength
• Optical microscopy

Correct Answer: Gel permeation chromatography (size exclusion chromatography)

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