An analyst who determines the strength, potency, and percentage purity of a drug or pharmaceutical product is performing:

• A. Special method
• B. Pharmaceutical assaying
• C. Identification test
• D. Pharmacopoeial test

Answer: (B)

Assay is the process of determining how much active drug is present and how pure it is, which directly measures strength and potency. In pharmaceutical quality control, analysts quantify the amount of active pharmaceutical ingredient and check for impurities, so the result is reported as a percentage of the labeled amount. For a tablet, this means calculating how much API is actually there compared to what the label claims, ensuring the product meets its stated potency and purity.

This differs from an identification test, which only confirms that the substance is what it is claimed to be, not how much of it is present. Pharmacopoeial tests encompass a range of procedures published in official compendia, including assays, but the specific activity described—determining strength, potency, and purity—is known as an assay. A term like “special method” isn’t the standard designation for this purpose.