Stability testing of natural products – protocol MCQs With Answer

Introduction: Stability testing of natural products – protocol MCQs With Answer is designed to help M.Pharm students master the principles and practical aspects of stability testing for herbal and natural product formulations. This collection focuses on regulatory protocols, stress testing, storage conditions, analytical methods, degradation pathways, packaging influence, and interpretation of stability data specific to botanicals. Questions emphasize ICH guidelines, photostability, microbial and chemical stability, stability-indicating method development, and shelf-life estimation for extracts, tinctures, powders, semisolids, and finished herbal products. Use these MCQs to prepare for examinations, practical protocol design, and quality control decision-making in herbal and cosmetic analysis.

Q1. Which ICH guideline is the primary reference for stability testing of new drug substances and products and is commonly applied to natural product formulations?

• ICH Q1A(R2) — Stability Testing of New Drug Substances and Products
• ICH Q3A — Impurities in New Drug Substances
• ICH Q2(R1) — Validation of Analytical Procedures
• ICH Q7 — Good Manufacturing Practice for Active Pharmaceutical Ingredients

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

Q2. Which of the following is the best description of a stability-indicating method in the context of natural products?

• An analytical method that quantifies only the parent marker compound without interference from excipients
• An assay that can accurately and specifically measure the active marker(s) in presence of degradation products, impurities and matrix components
• A qualitative fingerprinting method without quantitation
• A method used only for microbial limit testing of herbal formulations

Correct Answer: An assay that can accurately and specifically measure the active marker(s) in presence of degradation products, impurities and matrix components

Q3. For accelerated stability testing of herbal extracts, what is a commonly used accelerated storage condition recommended by ICH?

• 5 ± 3°C and 60% RH
• 25 ± 2°C and 60% RH
• 40 ± 2°C and 75% RH
• 50 ± 5°C and 40% RH

Correct Answer: 40 ± 2°C and 75% RH

Q4. Which degradation pathway is most commonly accelerated under high humidity conditions for hygroscopic herbal powders?

• Photodegradation
• Hydrolytic degradation
• Thermal polymerization
• Oxidative degradation

Correct Answer: Hydrolytic degradation

Q5. Photostability testing for herbal drug products specifically follows which ICH guideline?

• ICH Q1A(R2)
• ICH Q1B
• ICH Q2(R1)
• ICH Q3B

Correct Answer: ICH Q1B

Q6. In forced degradation studies for a herbal extract, which stress condition is used primarily to identify oxidation products?

• Exposure to strong acids and bases
• Heating at elevated temperatures in inert atmosphere
• Treatment with hydrogen peroxide or other oxidizing agents
• Photolytic exposure to UV-visible light

Correct Answer: Treatment with hydrogen peroxide or other oxidizing agents

Q7. When designing a stability protocol for a polyherbal topical cream, which additional test is particularly important compared to a single-compound drug?

• Single-point assay at time zero only
• Comprehensive microbiological preservative efficacy and challenge testing
• Only photostability testing under ambient light
• Viscosity measurement at 5°C only

Correct Answer: Comprehensive microbiological preservative efficacy and challenge testing

Q8. Which parameter is crucial to monitor in herbal oil formulations to assess oxidative rancidity during stability studies?

• pH
• Peroxide value
• Viscosity only
• Residual solvent content

Correct Answer: Peroxide value

Q9. For estimating shelf-life from accelerated stability data of an herbal API with first-order degradation kinetics, which extrapolation approach is commonly used?

• Arrhenius equation to extrapolate to long-term temperature
• Linear interpolation between 0 and 6 months only
• Direct use of accelerated data without correction
• Using only photostability results to estimate shelf-life

Correct Answer: Arrhenius equation to extrapolate to long-term temperature

Q10. Which analytical technique is most appropriate for simultaneous separation and quantitation of multiple marker compounds and degradation products in complex herbal matrices?

• UV-visible spectrophotometry single wavelength
• High-performance liquid chromatography with photodiode array or MS detection (HPLC-PDA/MS)
• Simple titration
• Thin-layer chromatography visualized with iodine only

Correct Answer: High-performance liquid chromatography with photodiode array or MS detection (HPLC-PDA/MS)

Q11. During stability testing, why is container-closure system evaluation particularly important for herbal products?

• Herbal products never interact with packaging materials
• Packaging can influence light, oxygen and moisture ingress affecting potency and degradation
• Only the color of the package matters for marketing
• Closure systems only affect microbial contamination but not chemical stability

Correct Answer: Packaging can influence light, oxygen and moisture ingress affecting potency and degradation

Q12. Which of the following is an appropriate sampling timepoint set for long-term stability study of a herbal finished product intended for a 24-month shelf-life under ICH conditions?

• 0, 1, 2, 3 months
• 0, 3, 6, 9, 12, 18, 24 months
• Only 0 and 24 months
• 0, 12, 36 months

Correct Answer: 0, 3, 6, 9, 12, 18, 24 months

Q13. What is the primary purpose of conducting preservative efficacy testing (PET) for aqueous herbal formulations during stability studies?

• To measure chemical potency of active markers
• To evaluate ability of preservative system to control microbial growth throughout shelf-life
• To determine photostability of preservatives
• To test packaging compatibility only

Correct Answer: To evaluate ability of preservative system to control microbial growth throughout shelf-life

Q14. Which of the following is a recommended practice when selecting marker compounds for stability studies of complex herbal extracts?

• Choose any compound present in trace amounts irrespective of biological relevance
• Select one or more representative markers that are pharmacologically relevant and analytically measurable, and track major degradation-prone constituents
• Only measure moisture content as a surrogate marker
• Use color intensity as the sole stability marker

Correct Answer: Select one or more representative markers that are pharmacologically relevant and analytically measurable, and track major degradation-prone constituents

Q15. In stability testing of a powdered herbal drug, which moisture-related test is most informative for predicting potential hydrolytic degradation and caking?

• Loss on drying (LOD) and water activity (aw)
• Peroxide value
• Disintegration time
• pH of an aqueous extract only

Correct Answer: Loss on drying (LOD) and water activity (aw)

Q16. What is the significance of stress testing (forced degradation) in method validation for herbal product stability studies?

• It is only used to shorten long-term studies
• To generate degradation products and demonstrate that the analytical method is specific and stability-indicating
• To confirm packaging is airtight
• To check taste profile changes under stress

Correct Answer: To generate degradation products and demonstrate that the analytical method is specific and stability-indicating

Q17. Which storage condition set is most appropriate for testing intermediate stability when accelerated results are marginal and additional data are required?

• 25°C ± 2°C/60% RH ± 5% RH
• 30°C ± 2°C/65% RH ± 5% RH
• 40°C ± 2°C/75% RH ± 5% RH
• 5°C ± 3°C with 30% RH

Correct Answer: 30°C ± 2°C/65% RH ± 5% RH

Q18. Which microbial parameter should be regularly monitored in herbal aqueous syrups during stability studies?

• Total viable aerobic count and absence of specified pathogens (e.g., E. coli, Salmonella)
• Only fungal identification once at release
• Gram stain of random samples only
• pH only, as an indirect microbial test

Correct Answer: Total viable aerobic count and absence of specified pathogens (e.g., E. coli, Salmonella)

Q19. When reporting stability data for commercialization of a herbal product, which of the following must be included in the stability protocol summary?

• Only the expiry date
• Storage conditions, testing intervals, test methods, specifications, container-closure system and shelf-life justification
• Only chromatograms without method description
• Only photographs of samples at each timepoint

Correct Answer: Storage conditions, testing intervals, test methods, specifications, container-closure system and shelf-life justification

Q20. Which factor uniquely complicates stability assessment of whole-plant herbal materials as opposed to single-entity APIs?

• Single defined chemical structure of all constituents
• Complex, variable multi-component composition leading to multiple degradation pathways and batch-to-batch variability
• Herbal materials are always chemically stable and require no testing
• They are inert and do not interact with excipients or packaging

Correct Answer: Complex, variable multi-component composition leading to multiple degradation pathways and batch-to-batch variability

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