Stability testing of drug products MCQs With Answer

Introduction: This quiz series on Stability testing of drug products is tailored for M.Pharm students studying Quality Management Systems (MQA 102T). It covers essential principles such as ICH guidelines, accelerated and long-term testing conditions, forced degradation, photostability, kinetics, container-closure effects, statistical evaluation, and regulatory expectations. Each question is crafted to deepen your conceptual understanding and to apply knowledge to practical scenarios encountered in stability study design, data interpretation, and shelf-life determination. Use these MCQs to test yourself, identify gaps, and prepare for advanced coursework or examinations in pharmaceutical stability and quality assurance.

Q1. Which ICH guideline is primarily referred to for general guidance on stability testing of new drug substances and products?

• ICH Q1B — Photostability Testing of New Drug Substances and Products
• ICH Q5C — Stability of Biotechnological/Biological Products
• ICH Q3C — Stability Testing for Impurities
• ICH Q1A(R2) — Stability Testing of New Drug Substances and Products

Correct Answer: ICH Q1A(R2) — Stability Testing of New Drug Substances and Products

Q2. What are the standard accelerated stability test conditions commonly used for drug products intended for long-term storage at 25°C?

• 60°C ± 2°C / 0% RH
• 30°C ± 2°C / 65% RH ± 5% RH
• 40°C ± 2°C / 75% RH ± 5% RH
• 5°C ± 3°C / 40% RH

Correct Answer: 40°C ± 2°C / 75% RH ± 5% RH

Q3. Which guideline specifically addresses photostability testing requirements for drug substances and products?

• ICH Q1A(R2)
• ICH Q1B
• ICH Q3A
• ICH Q5C

Correct Answer: ICH Q1B

Q4. Which description best defines a stability-indicating analytical method?

• An assay that quantifies impurities without measuring the active ingredient
• An assay that accurately and specifically measures the active ingredient in the presence of degradation products, excipients, and process impurities
• An assay that only measures total potency including degradation products
• An assay validated only for precision and accuracy at a single time point

Correct Answer: An assay that accurately and specifically measures the active ingredient in the presence of degradation products, excipients, and process impurities

Q5. The primary purpose of forced degradation (stress testing) in stability studies is to:

• Shorten the product shelf life by exposing it to extreme conditions
• Create degradation products to validate and develop stability-indicating analytical methods and to elucidate degradation pathways
• Replace long-term stability studies for regulatory submission
• Test only the container closure system without the product

Correct Answer: Create degradation products to validate and develop stability-indicating analytical methods and to elucidate degradation pathways

Q6. For a drug that follows first-order degradation kinetics, which plot will be linear?

• Percent remaining versus time
• Log of percent remaining (ln percentage) versus time
• Reciprocal of percent remaining versus time
• Square root of percent remaining versus time

Correct Answer: Log of percent remaining (ln percentage) versus time

Q7. When using the Arrhenius equation to extrapolate shelf life from accelerated stability data, what key assumption must hold?

• The product’s appearance remains unchanged at all temperatures
• The degradation mechanism and activation energy remain the same across the temperature range used
• The excipients evaporate at elevated temperatures
• The relative humidity is constant and irrelevant

Correct Answer: The degradation mechanism and activation energy remain the same across the temperature range used

Q8. What does “matrixing” in stability study design mean?

• Testing only the extremes of strength or container sizes and extrapolating for intermediate samples
• Testing a subset of samples at different time points so that not all combinations of factors are tested at every time point
• Testing all strengths, container sizes, and storage conditions at every time point
• Pooling samples from different batches into one test

Correct Answer: Testing a subset of samples at different time points so that not all combinations of factors are tested at every time point

Q9. Which property of the container-closure system primarily affects oxygen-sensitive drug degradation?

• Water vapor transmission rate
• Light transmittance at visible wavelengths
• Oxygen transmission rate or oxygen permeability of the closure
• Thermal conductivity of the container material

Correct Answer: Oxygen transmission rate or oxygen permeability of the closure

Q10. The Preservative Efficacy Test (PET) is most relevant for which type of product?

• Sterile single-dose injectables
• Non-sterile multi-dose aqueous formulations and topical products intended for repeated use
• Dry powder inhalers with no water content
• Intravenous admixtures prepared and used on the same day

Correct Answer: Non-sterile multi-dose aqueous formulations and topical products intended for repeated use

Q11. According to ICH Q1B, what are the recommended minimum light exposure values for photostability testing (visible and UV)?

• 10,000 lux hours visible; 5 watt-hours/m2 UV
• 1.2 million lux hours visible; 200 watt-hours/m2 UV
• 100 lux hours visible; 50 watt-hours/m2 UV
• 500,000 lux hours visible; 1000 watt-hours/m2 UV

Correct Answer: 1.2 million lux hours visible; 200 watt-hours/m2 UV

Q12. What is the difference between a “retest period” and a “shelf life” in regulatory stability terminology?

• Retest period applies to the drug product and shelf life to packaging material
• Retest period is used for APIs to indicate when reanalysis is needed; shelf life is for the finished drug product claimed by the manufacturer
• There is no difference; both terms are synonymous
• Retest period is shorter than shelf life by definition

Correct Answer: Retest period is used for APIs to indicate when reanalysis is needed; shelf life is for the finished drug product claimed by the manufacturer

Q13. What are the typical control tolerances for temperature and relative humidity in a stability chamber set to ICH long-term conditions (e.g., 25°C/60% RH)?

• ±10°C for temperature; ±20% RH
• ±2°C for temperature; ±5% RH
• ±0.1°C for temperature; ±0.5% RH
• ±5°C for temperature; ±15% RH

Correct Answer: ±2°C for temperature; ±5% RH

Q14. Which statistical method is most commonly applied to determine the shelf life (time to reach specification limit) from stability potency data?

• ANOVA comparing batch means only
• Linear regression analysis of potency versus time with prediction intervals
• Kaplan-Meier survival analysis
• Principal component analysis

Correct Answer: Linear regression analysis of potency versus time with prediction intervals

Q15. Photodegradation of a drug substance usually involves which primary molecular event?

• Thermal rearrangement without light absorption
• Absorption of photons leading to an excited electronic state and subsequent bond cleavage or reaction
• Sublimation of the drug into the gas phase
• Complete dissolution into the container material

Correct Answer: Absorption of photons leading to an excited electronic state and subsequent bond cleavage or reaction

Q16. Which of the following best describes “stress testing” in the context of stability studies?

• Testing the product at only recommended storage conditions
• Subjecting the drug substance/product to extreme pH, oxidation, light, heat, and humidity to generate degradation products for method development
• Randomly sampling marketed batches for potency
• Measuring dissolution only at room temperature

Correct Answer: Subjecting the drug substance/product to extreme pH, oxidation, light, heat, and humidity to generate degradation products for method development

Q17. A comprehensive stability protocol should include which of the following elements?

• Only the storage temperature and the product name
• Storage conditions, timepoints, number of batches, analytical methods, acceptance criteria, and packaging configuration
• Only the analytical methods without sampling schedule
• Only the accelerated study without long-term data

Correct Answer: Storage conditions, timepoints, number of batches, analytical methods, acceptance criteria, and packaging configuration

Q18. What is the main purpose of temperature mapping or qualification of a stability storage area?

• To calibrate analytical instruments used in testing
• To identify and document hot and cold spots and ensure the area maintains specified storage conditions uniformly
• To test the mechanical strength of storage racks
• To train personnel in sampling techniques

Correct Answer: To identify and document hot and cold spots and ensure the area maintains specified storage conditions uniformly

Q19. The term “t90” in stability studies refers to:

• The temperature at which 90% of samples pass specifications
• The time required for the drug product to degrade to 90% of its initial potency (i.e., 10% loss)
• The relative humidity at which 90% degradation occurs
• The number of test replicates required at each time point

Correct Answer: The time required for the drug product to degrade to 90% of its initial potency (i.e., 10% loss)

Q20. Which ICH guideline specifically provides recommendations for evaluating stability data and establishing storage conditions and shelf life based on the data?

• ICH Q1C
• ICH Q1E — Evaluation of Stability Data
• ICH Q2(R1)
• ICH Q3D

Correct Answer: ICH Q1E — Evaluation of Stability Data

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