Question

Which of the following is the limit for metals in drugs, expressed in terms of ppm of lead as per the Indian Pharmacopoeia (IP)?

• A. $10\text{ ppm}$
• B. $20\text{ ppm}$
• C. $50\text{ ppm}$
• D. $100\text{ ppm}$

Hint:

The general heavy metals limit test in many pharmacopoeias is traditionally bench-marked to a standard colorimetric comparison against $20\text{ ppm}$ of lead.

Answer 1

The Correct Option is B

Concept: The heavy metal limit test is a standard quality control procedure described in pharmacopoeias to detect and limit metallic impurities that can be toxic when present in pharmaceutical substances. The comparison is made by simulating reactions with a standard solution of lead, and the results are stated in parts per million (ppm). Step-by-Step Analysis:
• Pharmacopoeias lay down absolute thresholds for total heavy metal presence to guarantee patient safety.
• According to general standards set forth by the Indian Pharmacopoeia (IP) for overall heavy metal contamination limits across typical pharmaceutical substances and raw active ingredients, the baseline limit of general heavy metals calculated as lead ($\text{Pb}$) is designated as $20\text{ ppm}$.
• Substances exceeding this limit fail to comply with safety compliance frameworks due to the chronic toxicity risk associated with metal accumulation in biological systems. Therefore, option (B) represents the correct standard limitation.