Polymers play a central role in controlled release formulations, enabling precise modulation of drug delivery for oral, transdermal, injectable and implantable systems. In B.Pharm curricula, understanding biodegradable and non-biodegradable polymers, matrix and reservoir systems, release kinetics (zero‑order, first‑order, Higuchi, Korsmeyer‑Peppas), polymer‑drug interactions, and processing methods (solvent evaporation, hot‑melt extrusion, ionic gelation) is essential. Key materials such as PLGA, HPMC, Eudragit, chitosan and alginate are studied for their rate‑controlling, mucoadhesive and pH‑responsive properties. This focused MCQ set reinforces core concepts—polymer selection, characterization (GPC, DSC), mechanisms (diffusion, erosion, swelling) and formulation challenges—preparing you for exams and practical formulation design. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. What is the primary role of polymers in controlled release formulations?
- To control the rate and duration of drug release
- To enhance tablet color and taste
- To act as preservatives
- To increase drug solubility only
Correct Answer: To control the rate and duration of drug release
Q2. In which system is the drug uniformly dispersed throughout a polymer network?
- Reservoir system
- Matrix system
- Osmotic pump system
- Coated bead system
Correct Answer: Matrix system
Q3. Which polymer is a commonly used biodegradable material for controlled release (degrades into lactic and glycolic acids)?
- PLGA (poly(lactic-co-glycolic acid))
- HPMC (hydroxypropyl methylcellulose)
- Eudragit L100
- Carbopol
Correct Answer: PLGA (poly(lactic-co-glycolic acid))
Q4. Which polymer is widely used as a hydrophilic swellable matrix former for sustained oral delivery?
- HPMC (hydroxypropyl methylcellulose)
- Polyethylene
- PCL (polycaprolactone)
- Silicone rubber
Correct Answer: HPMC (hydroxypropyl methylcellulose)
Q5. Which mathematical model primarily describes diffusion-controlled drug release from a homogeneous matrix?
- Zero-order model
- First-order model
- Higuchi model
- Korsmeyer‑Peppas model
Correct Answer: Higuchi model
Q6. What defines zero-order release kinetics in controlled release formulations?
- Drug release rate decreases exponentially with time
- Drug release is proportional to remaining drug amount
- Drug is released at a constant rate independent of concentration
- Drug release follows Fickian diffusion only
Correct Answer: Drug is released at a constant rate independent of concentration
Q7. In the Korsmeyer‑Peppas equation for a slab geometry, an exponent n ≈ 0.5 indicates which mechanism?
- Fickian diffusion-controlled release
- Case II transport (relaxation-controlled)
- Super case II transport
- Pure erosion-controlled release
Correct Answer: Fickian diffusion-controlled release
Q8. Which polymer class is commonly used for enteric coatings that dissolve at intestinal pH?
- Eudragit L (enteric polymer)
- Polyethylene glycol (PEG)
- PLGA
- Hydroxyethyl cellulose
Correct Answer: Eudragit L (enteric polymer)
Q9. Which polymer is frequently used as a mucoadhesive excipient for buccal and nasal formulations?
- Carbopol (polyacrylic acid)
- Polyethylene
- PCL (polycaprolactone)
- Silicone oil
Correct Answer: Carbopol (polyacrylic acid)
Q10. Which manufacturing technique is commonly used to prepare polymeric microspheres by removing solvent to form solid particles?
- Solvent evaporation
- Lyophilization (freeze drying)
- Hot-melt compaction without solvent
- Direct compression
Correct Answer: Solvent evaporation
Q11. PLGA degradation proceeds primarily by hydrolysis of ester bonds to yield which monomers?
- Lactic acid and glycolic acid
- Glutamic acid and aspartic acid
- Ethylene glycol and propionic acid
- Acetic acid and succinic acid
Correct Answer: Lactic acid and glycolic acid
Q12. In osmotic pump tablets, which component is primarily responsible for controlling the drug release rate?
- Semipermeable membrane
- Tablet disintegrant
- Drug crystal shape
- Tablet colorant
Correct Answer: Semipermeable membrane
Q13. How does increasing polymer molecular weight typically affect drug release from a diffusion-controlled matrix?
- It increases the drug release rate
- It decreases the drug release rate
- It has no effect on release
- It always causes immediate release
Correct Answer: It decreases the drug release rate
Q14. Which sterilization method is least suitable for heat‑labile polymeric injectable formulations?
- Autoclaving (moist heat)
- 0.22 µm sterile filtration
- Ethylene oxide sterilization
- Gamma irradiation
Correct Answer: Autoclaving (moist heat)
Q15. Which polymer is commonly used as a rate‑controlling membrane in transdermal patches and some reservoir systems?
- Ethyl cellulose
- Hydroxypropyl methylcellulose (HPMC)
- PLGA
- Alginate
Correct Answer: Ethyl cellulose
Q16. Which polymer is known for thermoresponsive sol–gel transition and is used in injectable in situ gelling systems?
- Poloxamer 407 (Pluronic F127)
- Polyethylene
- Carbopol
- Cellulose acetate
Correct Answer: Poloxamer 407 (Pluronic F127)
Q17. What is the effect of increasing crosslinking density in a polymeric matrix on drug release?
- Increases swelling and accelerates release
- Decreases swelling and slows release
- Has no effect on release
- Causes polymer to dissolve immediately
Correct Answer: Decreases swelling and slows release
Q18. Which analytical technique is commonly used to determine polymer molecular weight distribution?
- Gel permeation chromatography (GPC)
- Differential scanning calorimetry (DSC)
- Fourier transform infrared spectroscopy (FTIR)
- Scanning electron microscopy (SEM)
Correct Answer: Gel permeation chromatography (GPC)
Q19. Which polymer is classified as non-biodegradable and often used for long-term implantable devices?
- Polyethylene
- PLGA
- Alginate
- Chitosan
Correct Answer: Polyethylene
Q20. Which release kinetic model describes a rate that is proportional to the remaining drug concentration?
- Zero-order kinetics
- First-order kinetics
- Higuchi model
- Korsmeyer‑Peppas model
Correct Answer: First-order kinetics
Q21. Which technique is used to measure the glass transition temperature (Tg) of a polymer?
- Differential scanning calorimetry (DSC)
- High-performance liquid chromatography (HPLC)
- Nuclear magnetic resonance (NMR)
- Ultraviolet spectroscopy (UV)
Correct Answer: Differential scanning calorimetry (DSC)
Q22. Which polymer property most directly affects diffusional drug release through a matrix?
- Porosity and tortuosity of the polymer matrix
- Polymer color
- Manufacturing label
- Tablet printing ink
Correct Answer: Porosity and tortuosity of the polymer matrix
Q23. What is the primary function of a plasticizer in polymer film formulations?
- Increase flexibility and reduce brittleness
- Increase the polymer melting point
- Act as the main rate-controlling agent
- Provide antimicrobial activity
Correct Answer: Increase flexibility and reduce brittleness
Q24. Which polymer is commonly used for mucoadhesive buccal patches due to its cationic nature and bioadhesion?
- Chitosan
- PLGA
- Ethyl cellulose
- Polyethylene
Correct Answer: Chitosan
Q25. Which natural polymer gels by ionic crosslinking with divalent calcium ions and is used for encapsulation?
- Alginate
- HPMC
- PLGA
- PEG
Correct Answer: Alginate
Q26. Which nanoparticle preparation technique uses ionic interaction between chitosan and tripolyphosphate?
- Ionic gelation
- Splay drying
- S olvent fusion
- Hot-melt extrusion
Correct Answer: Ionic gelation
Q27. Erosion-controlled release from a polymeric system is most influenced by which polymer attribute?
- Polymer hydrophilicity and susceptibility to hydrolysis
- Tablet colorant
- Printer barcode
- Outer packaging design
Correct Answer: Polymer hydrophilicity and susceptibility to hydrolysis
Q28. Which regulatory consideration is critical when developing polymeric controlled-release products?
- Biocompatibility and safety of polymer degradation products
- Choice of tablet embossing stamp
- Marketing slogan length
- Label font style
Correct Answer: Biocompatibility and safety of polymer degradation products
Q29. Which empirical model is frequently applied to analyze release from swelling-controlled polymer systems?
- Higuchi model
- Zero-order model
- Korsmeyer‑Peppas model
- First-order model
Correct Answer: Korsmeyer‑Peppas model
Q30. What major risk is associated with failure of the rate-controlling polymer coating in a reservoir formulation?
- Immediate dose dumping leading to toxicity
- Extended prolonged release with no effect
- Improved taste masking
- Reduced manufacturing cost
Correct Answer: Immediate dose dumping leading to toxicity
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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