MPharm Master of Pharmacy Pharmaceutical Microbiology and Biotechnology 1 — Questions and Answers
Question 1: Which sterilization method is most appropriate for heat-labile pharmaceutical products such as protein biologics?
- Autoclaving at 121°C
- Filtration through 0.22 µm membrane filters (Correct answer)
- Dry heat at 170°C
- Gamma irradiation at 25 kGy
Correct answer: Filtration through 0.22 µm membrane filters
Membrane filtration through 0.22 µm filters physically removes bacteria and fungi without exposing heat-labile biologics to damaging temperatures or radiation.
Question 2: What does the Bioburden test measure in pharmaceutical microbiology?
- The number of endotoxins per unit of product
- The total number of viable microorganisms present in or on a product before sterilization (Correct answer)
- The minimum inhibitory concentration of a preservative
- The sterility assurance level of a manufacturing environment
Correct answer: The total number of viable microorganisms present in or on a product before sterilization
Bioburden testing quantifies the microbial population on a product before final sterilization, which is essential for validating the sterilization process.
Question 3: Which organism is used as the biological indicator for validating steam sterilization (autoclaving) processes?
- Bacillus atrophaeus spores
- Geobacillus stearothermophilus spores (Correct answer)
- Staphylococcus aureus
- Clostridium sporogenes
Correct answer: Geobacillus stearothermophilus spores
Geobacillus stearothermophilus spores are the most heat-resistant organisms and are used as the standard biological indicator for moist heat (autoclave) sterilization validation.
Question 4: In aseptic manufacturing of injectable products, what is the purpose of the Media Fill (Process Simulation) test?
- To determine drug potency after manufacturing
- To simulate aseptic filling using sterile culture media to validate the process against contamination risk (Correct answer)
- To test the chemical compatibility of the container-closure system
- To measure particulate matter in the final product
Correct answer: To simulate aseptic filling using sterile culture media to validate the process against contamination risk
A Media Fill test uses growth-promoting culture media instead of drug product to challenge aseptic process integrity; incubated units must show no microbial growth.
Question 5: The limulus amebocyte lysate (LAL) test is used in pharmaceutical testing to detect:
- Bacterial endotoxins (pyrogens) from Gram-negative bacteria (Correct answer)
- Mycoplasma contamination in bioreactors
- Viral contamination in blood products
- Fungal biofilm formation
Correct answer: Bacterial endotoxins (pyrogens) from Gram-negative bacteria
The LAL test detects bacterial endotoxins (lipopolysaccharides from Gram-negative bacteria) in parenteral products; endotoxins cause fever and septic shock in patients.
Question 6: Which growth medium is used for the detection of Salmonella species in pharmaceutical raw materials per USP standards?
- Tryptic Soy Broth
- Rappaport Vassiliadis Soya Peptone (RVS) Broth with selective plating (Correct answer)
- Nutrient Broth
- Buffered Peptone Water alone
Correct answer: Rappaport Vassiliadis Soya Peptone (RVS) Broth with selective plating
Rappaport Vassiliadis Soya Peptone Broth is a selective enrichment broth that suppresses other flora while allowing Salmonella growth, followed by plating on selective agar.
