Drug–plastic interactions MCQs With Answer

Introduction:

This quiz collection on Drug–plastic interactions is designed for M.Pharm students studying Pharmaceutical Manufacturing Technology. It covers mechanisms by which drugs interact with polymeric packaging and processing plastics, including sorption, leaching, permeation, and chemical degradation. Emphasis is placed on common polymers (PVC, PE, PP, PET, EVA), plasticizers and additives, analytical approaches for extractables and leachables, and the impact of sterilization and storage conditions. Each question aims to test both theoretical understanding and practical considerations for formulation development, stability assessment, container–closure system selection, and regulatory expectations. Use these MCQs to deepen problem-solving skills and prepare for examinations and industry practice.

Q1. Which mechanism best describes the irreversible uptake of a low molecular weight drug into a polymer bulk causing decreased drug concentration in solution?

• Adsorption onto the polymer surface
• Sorption into the polymer matrix
• Permeation through the polymer to the external environment
• Surface precipitation on the polymer

Correct Answer: Sorption into the polymer matrix

Q2. Which polymer is most commonly associated with di(2-ethylhexyl) phthalate (DEHP) as a plasticizer concern for leachables?

• Polyethylene terephthalate (PET)
• Polypropylene (PP)
• Polyvinyl chloride (PVC)
• Polystyrene (PS)

Correct Answer: Polyvinyl chloride (PVC)

Q3. Which analytical approach is primary for identifying volatile and semi-volatile extractables from plastics?

• High-performance liquid chromatography (HPLC)
• Gas chromatography–mass spectrometry (GC–MS)
• Nuclear magnetic resonance (NMR)
• Size-exclusion chromatography (SEC)

Correct Answer: Gas chromatography–mass spectrometry (GC–MS)

Q4. What regulatory reference is frequently cited for packaging plastics and elastomers in pharmaceutical applications regarding extractables and leachables?

• USP <661> Plastic Packaging Systems and Their Materials of Construction
• ICH Q8 Pharmaceutical Development
• Ph. Eur. General Monograph on Tablets
• WHO Technical Report on Vaccines

Correct Answer: USP <661> Plastic Packaging Systems and Their Materials of Construction

Q5. Which factor most increases the rate of drug permeation through a polymeric container wall?

• Lower temperature during storage
• Higher polymer crystallinity
• Higher drug concentration gradient across the wall
• Use of thicker polymer films

Correct Answer: Higher drug concentration gradient across the wall

Q6. Which term describes small molecules released from plastics under exaggerated conditions used to predict potential leachables?

• Leachables
• Extractables
• Permeants
• Residues

Correct Answer: Extractables

Q7. Which sterilization method is most likely to alter polymer additives leading to increased extractables?

• Filtration through 0.22 µm membranes
• Gamma irradiation
• Dry heat of 40°C
• Storage at refrigerated conditions

Correct Answer: Gamma irradiation

Q8. For biologic drugs (proteins), which drug–plastic interaction is of greatest concern due to loss of biological activity?

• Sorption to hydrophobic polymer surfaces causing protein loss
• Permeation of buffer salts through the container wall
• Leaching of metal catalysts from polymerization
• Gas exchange through high-barrier films

Correct Answer: Sorption to hydrophobic polymer surfaces causing protein loss

Q9. Which polymer property correlates with greater permeability of small organic molecules?

• High glass transition temperature (Tg)
• High crosslink density
• Low free volume and high crystallinity
• High amorphous fraction and increased free volume

Correct Answer: High amorphous fraction and increased free volume

Q10. Which test strategy is most appropriate to predict clinically relevant leachables over shelf life?

• Short-term room temperature extractables by aggressive solvents only
• Accelerated and real-time leachable studies using actual drug product and packaging at intended conditions
• Identification of polymer additives without drug contact studies
• Only in silico migration modeling without experimental verification

Correct Answer: Accelerated and real-time leachable studies using actual drug product and packaging at intended conditions

Q11. Which additive class in plastics is primarily responsible for increased flexibility but may migrate into drug formulations?

• Stabilizers
• Plasticizers
• Fillers
• Antistatic agents

Correct Answer: Plasticizers

Q12. Which container–closure property is most critical to prevent oxygen ingress and oxidative degradation of sensitive drugs?

• Low water vapor transmission rate (WVTR)
• High oxygen barrier (low OTR)
• High transparency to visible light
• High tensile strength

Correct Answer: High oxygen barrier (low OTR)

Q13. Which analytical technique is best suited for quantifying non-volatile high molecular weight oligomeric leachables from polymers?

• Gas chromatography with flame ionization detector (GC–FID)
• Liquid chromatography–mass spectrometry (LC–MS)
• Headspace GC
• Fourier-transform infrared spectroscopy (FTIR) alone

Correct Answer: Liquid chromatography–mass spectrometry (LC–MS)

Q14. When a lipophilic drug partitions into plastic, which kinetic model often describes the uptake under excess polymer conditions?

• Zero-order release
• First-order decay in solution concentration
• Fickian diffusion-driven sorption (t1/2 proportional to film thickness squared)
• Michaelis–Menten kinetics

Correct Answer: Fickian diffusion-driven sorption (t1/2 proportional to film thickness squared)

Q15. Which polymer is generally preferred for parenteral bags due to low sorption of lipophilic drugs and minimal plasticizer migration?

• General purpose PVC with DEHP
• Polyolefin multilayer films or EVA-based bags
• Polystyrene single layer
• Cellulose acetate tubing

Correct Answer: Polyolefin multilayer films or EVA-based bags

Q16. What is the main purpose of an extractables study as part of container–closure qualification?

• To measure the rate of drug permeation through the polymer under normal use
• To identify potential chemical species that could leach under exaggerated conditions and inform targeted leachable testing
• To determine the mechanical strength of the packaging material
• To quantify microbial contamination from the polymer surface

Correct Answer: To identify potential chemical species that could leach under exaggerated conditions and inform targeted leachable testing

Q17. Which environmental condition commonly accelerates both plastic degradation and increased migration of additives into drug formulations?

• Low humidity cold storage
• High temperature and presence of UV radiation
• Neutral pH buffer at 4°C
• Storage under vacuum

Correct Answer: High temperature and presence of UV radiation

Q18. During formulation selection, which strategy can reduce sorption of hydrophobic drug molecules to plastic components?

• Decreasing drug concentration in the formulation regardless of therapeutic need
• Adding hydrophilic excipients or surfactants to reduce free drug partitioning into the polymer
• Switching to thinner plastic films to minimize contact
• Heating the formulation to increase polymer mobility

Correct Answer: Adding hydrophilic excipients or surfactants to reduce free drug partitioning into the polymer

Q19. Which measurement is most informative to assess aged polymer permeability to small molecules?

• Contact angle measurement only
• Permeability coefficient determination using diffusion cells
• Visual inspection for discoloration
• Shore hardness test

Correct Answer: Permeability coefficient determination using diffusion cells

Q20. Which mitigation approach is recommended when a critical drug shows unacceptable sorption to a chosen plastic administration set?

• Increase infusion duration to allow equilibrium sorption
• Use alternative materials (e.g., glass, coated tubing or different polymer) and pre-saturate with drug-containing solution if appropriate
• Introduce more plasticizers to the tubing to enhance flexibility
• Reduce drug potency to compensate for loss

Correct Answer: Use alternative materials (e.g., glass, coated tubing or different polymer) and pre-saturate with drug-containing solution if appropriate

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