Question

Which pharmacopoeial parameter directly detects foreign inorganic materials in crude drugs?

• A. Assay for active principle
• B. Loss on drying
• C. Total ash and acid-insoluble ash
• D. Thin layer chromatographic profile

Hint:

'Ash values' measure the inorganic residue left after a crude drug is burned. Since plant tissue burns away but minerals, sand and soil do not, ash testing reveals inorganic contamination.

Answer 1

The Correct Option is C

Concept:
'Ash values' measure the inorganic residue left after a crude drug is burned. Since plant tissue burns away but minerals, sand and soil do not, ash testing reveals inorganic contamination.

Step 1:
Total ash tells you the total mineral matter in the drug. Acid-insoluble ash specifically measures sand and silica that do not dissolve in acid — exactly the foreign inorganic material (dirt, earth) we want to detect.

Step 2:
Compare the others: assay measures the amount of active drug, loss on drying measures moisture (water content), and TLC profile checks the chemical fingerprint of organic constituents. None of these directly catch foreign inorganic matter.

Step 3:
Therefore the ash test is the parameter that directly detects foreign inorganic materials.

Answer: Option (3) — Total ash and acid-insoluble ash.