Stability testing of herbal drugs – principles and procedures MCQs With Answer

Stability testing of herbal drugs is essential to ensure safety, efficacy, and consistent quality of herbal formulations. B.Pharm students must learn core principles such as degradation pathways (hydrolysis, oxidation, photodegradation), stability-indicating methods, forced degradation studies, and relevant guidelines like ICH and WHO for storage conditions. Practical procedures include accelerated and long-term studies, packaging evaluation, moisture and microbial control, preservative efficacy testing, and analytical techniques (HPLC, TLC, UV, MS) for assay and impurity profiling. Understanding sampling, validation, documentation, and shelf-life estimation (Arrhenius approach) equips students for quality control, formulation optimization, and regulatory compliance. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the primary goal of stability testing for herbal drugs?

• To determine herbal color variations in different seasons
• To ensure safety, efficacy, and shelf life under specified storage conditions
• To maximize extraction yield from raw herbs
• To test consumer preference for taste

Correct Answer: To ensure safety, efficacy, and shelf life under specified storage conditions

Q2. Which guideline is most commonly referenced for stability testing of drug substances and products?

• ICH Q1A(R2)
• USP General Chapter 1111
• EMA Annex 15
• WHO GMP Part IV

Correct Answer: ICH Q1A(R2)

Q3. Which of the following is considered a forced degradation condition used to generate degradants?

• Storing at prescribed room temperature for 1 month
• Exposure to sunlight for a year
• Acid and base hydrolysis, oxidation, heat, and photolysis
• Packaging in amber bottles

Correct Answer: Acid and base hydrolysis, oxidation, heat, and photolysis

Q4. What are typical accelerated stability conditions used in many stability studies?

• 5°C and 30% RH
• 25°C and 40% RH
• 40°C and 75% RH
• 60°C and 10% RH

Correct Answer: 40°C and 75% RH

Q5. A stability-indicating method must primarily be able to:

• Quantify the main active marker only
• Separate and quantify the active marker and its degradation products
• Measure pH changes over time
• Assess microbial contamination only

Correct Answer: Separate and quantify the active marker and its degradation products

Q6. Which analytical technique is most suitable for profiling multiple phytochemical degradants with high sensitivity?

• TLC
• HPLC coupled with mass spectrometry (HPLC-MS)
• Organoleptic testing
• Gravimetric analysis

Correct Answer: HPLC coupled with mass spectrometry (HPLC-MS)

Q7. Photostability testing of herbal drugs is guided by which ICH document?

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

Correct Answer: ICH Q1B

Q8. In stability testing, what is the main purpose of container-closure system evaluation?

• To improve manufacturing speed
• To assess protection against moisture, oxygen, light and compatibility with the drug
• To decide label colors
• To verify marketing claims

Correct Answer: To assess protection against moisture, oxygen, light and compatibility with the drug

Q9. Which degradation pathway is most likely for phenolic compounds in herbal extracts?

• Caramelization
• Oxidation leading to quinone formation
• Polymerase chain reaction
• Isomerization to inactive stereoisomers

Correct Answer: Oxidation leading to quinone formation

Q10. During stability studies, microbial limit tests are important because herbal products:

• Never support microbial growth
• Can be susceptible to microbial contamination and spoilage
• Only contain preservatives that guarantee sterility
• Are always administered parenterally

Correct Answer: Can be susceptible to microbial contamination and spoilage

Q11. The Arrhenius equation in stability testing is used to:

• Estimate the effect of pH on solubility
• Predict shelf life by relating reaction rate to temperature
• Measure humidity dependence of dissolution
• Calculate dissolution at various stirring speeds

Correct Answer: Predict shelf life by relating reaction rate to temperature

Q12. Which parameter is NOT typically assessed in physical stability of herbal semisolid formulations?

• Viscosity
• Phase separation
• Melting point of raw excipient
• Color and odor changes

Correct Answer: Melting point of raw excipient

Q13. Preservative efficacy testing (challenge test) evaluates:

• The antioxidant capacity of herbal actives
• The ability of a preservative system to inhibit microbial growth over time
• The solubility of preservatives in water
• The color stability of preservatives

Correct Answer: The ability of a preservative system to inhibit microbial growth over time

Q14. For herbal products, selection of marker compound(s) for stability study should be based on:

• Only the most abundant compound regardless of activity
• Known bioactive constituents or compounds representative of the herbal matrix
• Only volatile oils because they are easy to analyze
• Any compound that smells strong

Correct Answer: Known bioactive constituents or compounds representative of the herbal matrix

Q15. Which of the following is a sign of chemical instability in a herbal liquid formulation?

• Increase in viscosity
• pH drift and decrease in assay due to degradation
• Improved flavor over time
• Reduction in container weight

Correct Answer: pH drift and decrease in assay due to degradation

Q16. Why is specificity an important validation parameter for a stability-indicating method?

• It ensures the method measures only the analyte of interest in the presence of degradants and excipients
• It guarantees faster run times
• It reduces solvent consumption
• It improves sample throughput in manufacturing

Correct Answer: It ensures the method measures only the analyte of interest in the presence of degradants and excipients

Q17. Which stress condition is most appropriate to evaluate hydrolytic degradation?

• Exposure to neutral air at room temperature
• Acidic and alkaline aqueous conditions at elevated temperature
• Exposing to UV light only
• Freezing at -20°C

Correct Answer: Acidic and alkaline aqueous conditions at elevated temperature

Q18. In herbal stability studies, why are extract standardization and batch-to-batch consistency important?

• They ensure identical color across batches
• They guarantee consistent levels of active marker(s) and predictable stability behavior
• They reduce the need for packaging studies
• They eliminate the requirement for microbial testing

Correct Answer: They guarantee consistent levels of active marker(s) and predictable stability behavior

Q19. Which parameter is commonly monitored to detect oxidation of herbal constituents?

• Loss on drying
• Increase in peroxide value or appearance of specific oxidized degradants
• Particle size distribution
• Freezing point depression

Correct Answer: Increase in peroxide value or appearance of specific oxidized degradants

Q20. What is the role of hygroscopicity testing in herbal drug stability?

• To evaluate taste masking efficiency
• To assess moisture uptake which can accelerate degradation or cause physical changes
• To determine color fastness
• To measure antimicrobial activity

Correct Answer: To assess moisture uptake which can accelerate degradation or cause physical changes

Q21. Which storage condition is typically used for long-term stability testing in temperate climates?

• 5°C ± 3°C
• 30°C ± 2°C / 65% RH ± 5% RH
• 25°C ± 2°C / 60% RH ± 5% RH
• 50°C ± 5°C

Correct Answer: 25°C ± 2°C / 60% RH ± 5% RH

Q22. During stability testing, which documentation is essential for regulatory submissions?

• Marketing brochure
• Complete study protocol, raw data, chromatograms, validated methods, and stability report
• Only final expiration date
• Only photographs of packaging

Correct Answer: Complete study protocol, raw data, chromatograms, validated methods, and stability report

Q23. Which of the following is a limitation when applying conventional pharmaceutical stability approaches to herbal products?

• Herbal products are always chemically simple
• Complex multi-component matrices and variable marker content complicate stability interpretation
• Herbal drugs do not undergo oxidation
• Herbal products are sterile so microbial testing is unnecessary

Correct Answer: Complex multi-component matrices and variable marker content complicate stability interpretation

Q24. A stability-indicating HPLC method must demonstrate:

• That the active peak is well resolved from impurities and degradation products
• Only that the method is fast
• Only the detection of the largest peak
• That mass spectrometry is not required

Correct Answer: That the active peak is well resolved from impurities and degradation products

Q25. Which assessment would help predict photodegradation susceptibility of an herbal active?

• Measuring water solubility only
• Determining UV-visible absorption spectrum and exposing to light in ICH photostability chamber
• Measuring melting point
• Conducting only microbial limit tests

Correct Answer: Determining UV-visible absorption spectrum and exposing to light in ICH photostability chamber

Q26. What is the main reason to include placebo (excipients without active) in stability studies?

• To reduce study costs
• To evaluate excipient compatibility and contribution to overall instability
• To improve taste of samples
• Placebo samples are not relevant in stability testing

Correct Answer: To evaluate excipient compatibility and contribution to overall instability

Q27. Which parameter should be checked for herbal ointments during stability studies?

• Cloud point only
• Spreadability, phase separation, pH (if applicable), and microbial limits
• Dielectric constant
• Boiling point

Correct Answer: Spreadability, phase separation, pH (if applicable), and microbial limits

Q28. If an herbal drug shows first-order degradation kinetics, what does that imply?

• Rate of degradation is constant and independent of concentration
• Rate of degradation depends linearly on the concentration of the drug
• There is no degradation
• Degradation depends on square of concentration

Correct Answer: Rate of degradation depends linearly on the concentration of the drug

Q29. Which technique is most useful for rapid screening of multiple herbal samples for stability-related changes in fingerprint profile?

• Single-wavelength UV measurement
• TLC or HPTLC fingerprinting
• Osmolarity measurement
• Thermogravimetric analysis only

Correct Answer: TLC or HPTLC fingerprinting

Q30. When assigning an expiry date based on stability data, the decision should be based on:

• Manufacturer preference only
• Statistical analysis of stability data, specifications, and acceptable limits for potency and safety
• Marketing timelines
• Color retention alone

Correct Answer: Statistical analysis of stability data, specifications, and acceptable limits for potency and safety

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