Determination of foreign matter in herbal drugs MCQs With Answer

Determination of foreign matter in herbal drugs is a fundamental topic in Herbal and Cosmetic Analysis for M.Pharm students. This blog-style MCQ set focuses on identification, quantification and regulatory aspects of foreign matter in crude and processed botanical materials. Questions emphasize practical laboratory procedures (sampling, separation, drying, weighing), instruments (stereomicroscope, sieves, riffle splitters), classification of contaminants (organic vs inorganic), and decision criteria based on pharmacopoeial monographs. These MCQs are designed to strengthen conceptual understanding and exam readiness by reflecting real-world analytical steps, quality control implications and corrective actions for contaminated herbal lots. Use the questions to test knowledge and practice application of standard methods.

Q1. What best defines “foreign matter” in herbal drugs?

• Any part of the labeled plant material used for therapeutic effect
• Any extraneous inorganic or organic material not inherent to the intended plant drug
• Only inorganic particles such as sand and stones present in the sample
• Only microbial contamination including bacteria and fungi

Correct Answer: Any extraneous inorganic or organic material not inherent to the intended plant drug

Q2. Which of the following is an example of organic foreign matter in a herbal sample?

• Sand particles
• Stones
• Fragments of a different plant species
• Metal shavings

Correct Answer: Fragments of a different plant species

Q3. Which item is typically classified as inorganic foreign matter?

• Pieces of stem from the labeled plant
• Insect fragments
• Soil and sand
• Unrelated plant leaves

Correct Answer: Soil and sand

Q4. What is the most commonly used technique to remove and quantify foreign matter from crude herbal drugs in the laboratory?

• Centrifugation at high speed
• Hand-picking under magnification using forceps or tweezers
• Chemical digestion of the sample
• Gas chromatography

Correct Answer: Hand-picking under magnification using forceps or tweezers

Q5. Which instrument is most helpful for visual detection and separation of small foreign particles in herbal samples?

• UV–Vis spectrophotometer
• Stereomicroscope (dissecting microscope)
• pH meter
• Fourier-transform infrared spectrometer

Correct Answer: Stereomicroscope (dissecting microscope)

Q6. How is the amount of foreign matter usually expressed after analysis?

• As volume per unit volume (mL/mL)
• As a count per gram
• As percentage w/w of the test sample
• As a logarithmic purity score

Correct Answer: As percentage w/w of the test sample

Q7. Which sampling method is recommended to obtain a representative portion from a large bulk of herbal material?

• Picking randomly from the top of the lot
• Riffle splitting or coning and quartering to reduce sample size representatively
• Sampling only from the shipment packaging
• Taking only a single small scoop from the center

Correct Answer: Riffle splitting or coning and quartering to reduce sample size representatively

Q8. For powdered herbal drugs, which preparatory step is critical before weighing foreign matter to ensure accurate results?

• Sterilization by autoclaving
• Drying to constant weight to remove moisture
• Dissolving the powder in water
• Heating to 300 °C to burn organic residues

Correct Answer: Drying to constant weight to remove moisture

Q9. Which tool is typically used to separate coarse particles or large foreign matter from powdered herbal materials?

• Analytical centrifuge
• Sieve or series of sieves with defined mesh sizes
• Gas chromatograph
• pH indicator paper

Correct Answer: Sieve or series of sieves with defined mesh sizes

Q10. Which of the following best indicates poor harvesting and primary processing practices?

• Presence of well-dried, intact plant parts only
• Uniform particle size
• High levels of soil, stones and mineral grit
• Consistent moisture content within specifications

Correct Answer: High levels of soil, stones and mineral grit

Q11. What is the correct sequence of major steps when determining foreign matter in a crude herbal sample?

• Weigh sample → homogenize → calculate percentage → separate foreign matter
• Homogenize sample → separate foreign matter → dry/weigh foreign matter → calculate percentage
• Separate foreign matter → dissolve sample → run HPLC → report
• Autoclave sample → count foreign particles → report

Correct Answer: Homogenize sample → separate foreign matter → dry/weigh foreign matter → calculate percentage

Q12. Which statement about acceptable limits for foreign matter in herbal drugs is correct?

• There are universal numerical limits that apply to all herbs regardless of monograph
• Acceptable limits are specified in individual pharmacopoeial monographs or regulatory guidance
• Foreign matter limits are not relevant for herbal quality control
• Limits are always set at 10% w/w for every herb

Correct Answer: Acceptable limits are specified in individual pharmacopoeial monographs or regulatory guidance

Q13. Which corrective action is most appropriate if a tested herbal batch contains foreign matter above the monograph limit?

• Approve the batch and reduce the labeled dose
• Reject the batch or subject it to approved cleaning/reprocessing to reduce foreign matter
• Ignore the result and proceed to packaging
• Increase the production temperature during drying to destroy foreign matter

Correct Answer: Reject the batch or subject it to approved cleaning/reprocessing to reduce foreign matter

Q14. What type of foreign matter is best removed by air aspiration or blowing techniques?

• Heavy stones and metal pieces
• Light dust, chaff and very fine vegetative debris
• Embedded insect frass within hard seeds
• Large woody stems

Correct Answer: Light dust, chaff and very fine vegetative debris

Q15. When reporting foreign matter as percentage w/w, which calculation is correct?

• (Weight of foreign matter / Weight of original test sample) × 100
• (Weight of cleaned sample / Weight of foreign matter) × 100
• (Number of foreign particles / Total particles) × 100
• (Weight of original sample / Weight of foreign matter) × 100

Correct Answer: (Weight of foreign matter / Weight of original test sample) × 100

Q16. Which observation during foreign matter determination suggests contamination by storage pests?

• Uniform color and texture across the batch
• Presence of live or dead insects, frass and webbing
• Only occasional soil particles
• Presence of expected plant seeds only

Correct Answer: Presence of live or dead insects, frass and webbing

Q17. For whole or broken crude herbal drugs, what is a commonly recommended test sample size for foreign matter determination used in many pharmacopeial procedures?

• 0.1 g
• 1 g
• 100 g
• 10 kg

Correct Answer: 100 g

Q18. Which of the following best describes “extraneous vegetable matter” in a batch of a labeled botanical drug?

• Non-plant debris such as stones and metal
• Parts of the labeled plant intentionally included in the drug
• Plant material from other species unintentionally present in the sample
• Moisture present within cells of the labeled plant

Correct Answer: Plant material from other species unintentionally present in the sample

Q19. Why is microscopic examination important after initial visual separation of foreign matter?

• Microscopy is cheaper than visual inspection
• It confirms identity of small or ambiguous particles such as insect fragments, other plant tissues or spores
• It eliminates the need to weigh foreign matter
• It increases the moisture content of the sample

Correct Answer: It confirms identity of small or ambiguous particles such as insect fragments, other plant tissues or spores

Q20. Which quality attribute of an herbal drug can be directly affected by unremoved foreign matter?

• Only the color of the product, nothing else
• Safety, efficacy and stability of the final product
• Only the fragrance without any impact on safety
• Foreign matter has no impact on any quality attribute

Correct Answer: Safety, efficacy and stability of the final product

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