Introduction: Quality control of rubber closures and secondary packaging materials is essential knowledge for B.Pharm students. This topic covers material selection (butyl, bromobutyl, chlorobutyl, natural rubber), physical tests (compression set, tensile strength, Shore A hardness), container closure integrity, extractables and leachables, particulate and sterility concerns, and compatibility with sterilization methods. You will also learn secondary packaging tests such as seal strength, oxygen and water vapor transmission rates, migration testing for inks/adhesives, and regulatory expectations (USP chapters, CoA, GMP). Mastery of these concepts ensures product safety, stability, and regulatory compliance. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which elastomer is most commonly used for parenteral stoppers due to low gas permeability and chemical inertness?
- Natural rubber latex
- SBR (Styrene-butadiene rubber)
- Butyl rubber
- Silicone rubber
Correct Answer: Butyl rubber
Q2. Which container closure integrity test is non‑destructive and suitable for routine release of sterile products?
- Dye ingress (methylene blue) test
- Vacuum decay test
- Microbial ingress immersion test
- High-voltage leak detection
Correct Answer: Vacuum decay test
Q3. Which test parameter quantifies permanent deformation of a rubber stopper after prolonged compression?
- Compression set
- Tensile strength
- Elongation at break
- Shore A hardness
Correct Answer: Compression set
Q4. Which analytical technique is most appropriate for identifying non-volatile leachables extracted from rubber closures?
- Gas chromatography–mass spectrometry (GC‑MS)
- Ultraviolet–visible spectrophotometry (UV‑Vis)
- Liquid chromatography–mass spectrometry (LC‑MS)
- Fourier transform infrared spectroscopy (FTIR)
Correct Answer: Liquid chromatography–mass spectrometry (LC‑MS)
Q5. Which sterilization method is least likely to induce significant thermal degradation of elastomeric closures?
- Autoclaving (steam at 121°C)
- Gamma irradiation
- Dry heat sterilization
- Ethylene oxide (EtO) sterilization
Correct Answer: Ethylene oxide (EtO) sterilization
Q6. What is the main purpose of siliconization of rubber stoppers used in vials and syringes?
- Increase water permeability
- Improve lubricity and reduce coring during needle puncture
- Enhance microbial adhesion
- Increase Shore A hardness
Correct Answer: Improve lubricity and reduce coring during needle puncture
Q7. Which of the following tests evaluates particle generation when a needle punctures a rubber stopper repeatedly?
- Compression set test
- Septum puncture particulate test
- Shore A hardness test
- OTR (oxygen transmission rate) test
Correct Answer: Septum puncture particulate test
Q8. Which compound class is a common plasticizer and a frequent target in extractables/leachables studies of rubber closures?
- Phthalates (e.g., dioctyl phthalate)
- Alkylbenzenes
- Saccharin derivatives
- Siloxanes only
Correct Answer: Phthalates (e.g., dioctyl phthalate)
Q9. Which instrument is routinely used to measure Shore A hardness of rubber closures?
- Universal testing machine (UTM)
- Shore durometer
- Gas chromatograph
- Atomic force microscope
Correct Answer: Shore durometer
Q10. For secondary packaging of moisture‑sensitive pharmaceuticals, which material offers the best moisture barrier?
- Paperboard carton
- Polyethylene film
- Aluminum foil laminate
- Non‑coated PVC
Correct Answer: Aluminum foil laminate
Q11. Which test directly measures the rate at which oxygen permeates through a packaging film?
- Water vapor transmission rate (WVTR)
- Oxygen transmission rate (OTR)
- Seal strength test
- MVTR (moisture vapor transmission rate)
Correct Answer: Oxygen transmission rate (OTR)
Q12. Which USP chapter specifically addresses assessment of extractables and leachables for packaging components?
- USP <71>
- USP <62>
- USP <1663>
- USP <1207>
Correct Answer: USP <1663>
Q13. Which stopper characteristic is most critical for lyophilized drug vials to maintain vacuum and prevent moisture ingress?
- High Shore A hardness
- Low gas permeability and excellent seal integrity
- High particulate release
- High swell in aqueous solutions
Correct Answer: Low gas permeability and excellent seal integrity
Q14. Visual inspection of rubber closures is intended to detect which of the following?
- Sub‑visible particulates only
- Surface defects, cracks, inclusions and discoloration
- Internal chemical degradation products
- Exact oxygen transmission rate
Correct Answer: Surface defects, cracks, inclusions and discoloration
Q15. What does “coring” refer to in the context of rubber stoppers and needles?
- A type of seal integrity test
- Formation of fragments of rubber removed by needle puncture
- Measurement of Shore A hardness
- An aging protocol for stoppers
Correct Answer: Formation of fragments of rubber removed by needle puncture
Q16. Which test is used to quantify the adhesive strength of carton seals in secondary packaging?
- Peel strength test
- Compression set test
- Dye penetration test
- Helium leak test
Correct Answer: Peel strength test
Q17. Which laboratory instrument is used to measure tensile strength and elongation at break of elastomeric closures?
- UV‑Vis spectrophotometer
- Universal testing machine (UTM)
- Gas permeability analyzer
- Shore durometer
Correct Answer: Universal testing machine (UTM)
Q18. Which assay is used to detect bacterial endotoxin contamination potentially introduced from packaging materials used for injectables?
- Ames test
- Limulus Amebocyte Lysate (LAL) test
- Bradford protein assay
- pH titration
Correct Answer: Limulus Amebocyte Lysate (LAL) test
Q19. In blister packaging of tablets, which coating is commonly applied to PVC to improve oxygen barrier properties?
- Polyethylene (PE) coating
- PVDC (polyvinylidene chloride) coating
- Polypropylene (PP) varnish
- Natural rubber latex layer
Correct Answer: PVDC (polyvinylidene chloride) coating
Q20. Which material is generally avoided for injectable stoppers because of allergy risk from natural proteins?
- Bromobutyl rubber
- Natural rubber latex
- Chlorobutyl rubber
- Synthetic butyl rubber blends
Correct Answer: Natural rubber latex
Q21. Which highly sensitive tracer gas method is used for nondestructive leak detection of container closure systems?
- Dye ingress
- Vacuum decay
- Helium leak detection
- Bubble immersion test
Correct Answer: Helium leak detection
Q22. What unit is commonly used to express water vapor transmission rate (WVTR) of packaging films?
- mg/day
- g/m²/day
- ppm
- mL/hour
Correct Answer: g/m²/day
Q23. Which mechanical parameter describes rubber resistance to deformation at a specified elongation (often reported at 100% elongation)?
- Compression set
- 100% modulus
- Shore A hardness
- Elongation at break
Correct Answer: 100% modulus
Q24. To confirm compatibility of a stopper liner with a drug product, which study is essential?
- Seal strength test only
- Extractables and leachables study
- Shore hardness profiling
- Visual inspection only
Correct Answer: Extractables and leachables study
Q25. Which testing is required to ensure that printing inks and adhesives in secondary packaging do not migrate into the product?
- Microbial challenge test
- Migration testing
- Helium leak test
- Compression set
Correct Answer: Migration testing
Q26. What sterility assurance level (SAL) is typically required for terminally sterilized parenteral products?
- 10⁰
- 10⁻²
- 10⁻⁶
- 10⁻¹²
Correct Answer: 10⁻⁶
Q27. During capping/crimping of vials, which parameter is critical to ensure a uniform hermetic seal?
- Crimp height and sealing force
- Shore A hardness of cardboard carton
- Ink drying time on label
- OTR of primary container
Correct Answer: Crimp height and sealing force
Q28. Which regulatory document do manufacturers usually provide to confirm that a batch of closures meets specified test results?
- Certificate of Analysis (CoA)
- Environmental monitoring report
- Pharmacopoeial monograph text
- Clinical trial protocol
Correct Answer: Certificate of Analysis (CoA)
Q29. Which standard or guideline is commonly referenced for package integrity and sterilization validation of sterile medical packaging (also used in pharma context)?
- ICH Q3A
- ISO 11607
- USP <800>
- ICH Q9
Correct Answer: ISO 11607
Q30. Which physical test assesses whether a laminated pouch or sachet will remain sealed under expected transport and storage stresses?
- Helium leak detection
- Accelerated aging without mechanical testing
- Seal strength (peel/tensile) and burst test
- Microbial endotoxin assay
Correct Answer: Seal strength (peel/tensile) and burst test
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