Qualification of membrane filtration systems MCQs With Answer

Introduction: Qualification of membrane filtration systems MCQs With Answer

This blog provides focused multiple-choice questions (MCQs) tailored for M.Pharm students preparing for Pharmaceutical Validation examinations. It emphasizes qualification principles for membrane filtration systems used to sterilize or clarify pharmaceutical liquids, covering design, installation, operational and performance qualifications (DQ/IQ/OQ/PQ), integrity test methods, bacterial retention and challenge testing, filter selection and sizing, compatibility with process conditions, and post-sterilization verification. Each question is designed to deepen conceptual understanding and application of regulatory expectations, test methods (bubble point, pressure hold, forward flow), and documentation requirements. Answers are provided for self-assessment and to reinforce critical validation practices used in sterile drug manufacture.

Q1. What is the primary objective of Performance Qualification (PQ) for a membrane filtration system?

• To document laboratory bench testing of new membrane materials
• To verify that the installed system operates within specified limits under simulated worst-case conditions
• To confirm that the system design meets user requirements on paper
• To perform routine clean-in-place (CIP) procedures

Correct Answer: To verify that the installed system operates within specified limits under simulated worst-case conditions

Q2. Which organism is most commonly used in bacterial challenge tests to validate sterilizing-grade membrane filters?

• Escherichia coli
• Brevundimonas diminuta
• Staphylococcus aureus
• Pseudomonas aeruginosa

Correct Answer: Brevundimonas diminuta

Q3. Which test is most appropriate for detecting gross defects in a liquid filtration membrane housing before use?

• Bubble point test
• Microbial culture of filtrate
• Visual inspection only
• Differential pressure integrity (pressure hold) test

Correct Answer: Bubble point test

Q4. What pore size is generally accepted as sterilizing-grade for membrane filtration of parenteral solutions?

• 10.0 µm
• 0.45 µm
• 0.22 µm
• 1.2 µm

Correct Answer: 0.22 µm

Q5. During Installation Qualification (IQ) of a membrane filter assembly, which activity is essential?

• Performing a bacterial challenge test
• Documenting filter lot numbers, housing material and system connections
• Establishing routine production schedules
• Assessing long-term filter performance in daily production

Correct Answer: Documenting filter lot numbers, housing material and system connections

Q6. Which integrity test is most sensitive to small leaks and commonly used post-sterilization for membrane filters?

• Forward flow rate test
• Bubble point test
• Visual filter surface inspection
• Bulk sterility testing of large volume

Correct Answer: Bubble point test

Q7. In an Operational Qualification (OQ) for membrane filtration, which parameter should be experimentally challenged and documented?

• Filter color
• Maximum allowable transmembrane pressure and flow rate performance
• Company logo on filter packaging
• Theoretical calculations only without tests

Correct Answer: Maximum allowable transmembrane pressure and flow rate performance

Q8. What is the primary rationale for performing prefiltering (using larger pore prefilters) before final 0.22 µm filtration?

• To increase bacterial load before final filtration
• To remove particulate load and extend the life of the sterilizing filter
• To sterilize the solution prior to final filtration
• To change pH of the process fluid

Correct Answer: To remove particulate load and extend the life of the sterilizing filter

Q9. Which statement about bubble point and diffusion (pressure hold) tests is correct?

• Bubble point measures gas flow at low pressure while diffusion measures the pressure at which a continuous stream of bubbles is produced
• Bubble point detects gross membrane damage; diffusion provides a quantitative leak rate and is more sensitive to small defects
• Both tests are identical in principle and sensitivity
• Diffusion test is only used for gas filters and not for liquid filtration systems

Correct Answer: Bubble point detects gross membrane damage; diffusion provides a quantitative leak rate and is more sensitive to small defects

Q10. Which documentation is critical to retain after completing qualification of a membrane filtration system?

• Only a summary memo with no raw data
• Complete IQ, OQ, PQ protocols, raw data, acceptance criteria, and change control records
• Only final product release certificates
• Only vendor brochures for membrane filters

Correct Answer: Complete IQ, OQ, PQ protocols, raw data, acceptance criteria, and change control records

Q11. For a bacterial retention test, what is a typical minimum challenge concentration used to demonstrate retention of a sterilizing-grade filter?

• Less than 10 CFU/mL
• ~10^3 CFU/mL
• ~10^7 CFU per test sample
• No challenge organisms are used

Correct Answer: ~10^7 CFU per test sample

Q12. Why is it important to perform an integrity test both before and after sterilization of a membrane filter?

• Sterilization can alter membrane properties or cause damage; pre- and post-tests ensure filter integrity was maintained
• Post-sterilization tests are unnecessary if pre-test passed
• Only pre-sterilization testing is required by regulators
• To change the filter pore size during sterilization

Correct Answer: Sterilization can alter membrane properties or cause damage; pre- and post-tests ensure filter integrity was maintained

Q13. Which factor is least likely to affect membrane filter performance during validation?

• Solution viscosity and temperature
• Transmembrane pressure and flow rate
• Operator astrological sign
• Chemical compatibility of membrane with process fluids

Correct Answer: Operator astrological sign

Q14. When sizing a sterilizing-grade membrane filter for a process, which calculation is most important?

• Filter surface area required to maintain acceptable flow rate at target transmembrane pressure considering viscosity
• Number of operators required to change the filter
• Shipping weight of filter housing
• Visual appearance of the membrane

Correct Answer: Filter surface area required to maintain acceptable flow rate at target transmembrane pressure considering viscosity

Q15. Which integrity test is particularly useful for detecting wetting or hydrophobic membrane defects under forward flow conditions?

• Bubble point test only
• Forward flow/air diffusion test
• Visual inspection under black light
• Gram staining of membrane surface

Correct Answer: Forward flow/air diffusion test

Q16. What is an appropriate acceptance criterion for a pressure hold (diffusion) integrity test on a 0.22 µm sterilizing filter?

• Any detectable pressure decay is acceptable
• Decay rate must be less than a defined limit based on filter area and vendor specification
• Immediate loss of all pressure
• No need to specify limits; judge by operator experience

Correct Answer: Decay rate must be less than a defined limit based on filter area and vendor specification

Q17. Which action is recommended if a filter fails integrity after sterilization but before production use?

• Use the filter anyway if visual inspection looks fine
• Discard or quarantine the filter and investigate root cause, then requalify or replace
• Continue with increased production speed
• Reduce the challenge organism concentration in future tests

Correct Answer: Discard or quarantine the filter and investigate root cause, then requalify or replace

Q18. In validation, what is the purpose of performing worst-case studies for membrane filtration?

• To identify conditions under which the process is most challenged (e.g., highest viscosity, load) and ensure control limits are adequate
• To avoid testing and save time
• To use the smallest possible filter area
• To prove that qualification is unnecessary

Correct Answer: To identify conditions under which the process is most challenged (e.g., highest viscosity, load) and ensure control limits are adequate

Q19. Which regulatory expectation applies to membrane filter change control after initial qualification?

• Any change in filter type, vendor, lot, or critical process parameters requires assessment and possibly requalification
• Filters may be changed freely without documentation
• Only changes to building structure require change control
• Filter changes are only documented at annual audits

Correct Answer: Any change in filter type, vendor, lot, or critical process parameters requires assessment and possibly requalification

Q20. For single-use membrane filter assemblies in aseptic processes, which qualification point is particularly important?

• Assessing leachables/extractables and material compatibility with process fluids as part of DQ/OQ/PQ
• Ensuring the assembly cannot be autoclaved
• Verifying the assembly color matches production area décor
• Only performing a visual check before use

Correct Answer: Assessing leachables/extractables and material compatibility with process fluids as part of DQ/OQ/PQ

G S Sachin

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