What type of test measures the amount of active ingredient in a drug?

Potency assays are specifically designed to measure the strength or concentration of an active ingredient in a drug. They assess the biological activity of a drug in relation to a standard, ensuring that the amount of the active ingredient present produces the expected pharmacological effect. This is critical in pharmaceutical manufacturing and quality control, as it ensures that each batch of a drug contains the correct dosage necessary for efficacy.

Activity assays and ELISA (Enzyme-Linked Immunosorbent Assay) serve different purposes. While activity assays might evaluate the biological or pharmacological function of a compound, they do not necessarily quantify the amount of active ingredient directly. ELISA is a widely used technique for detecting and quantifying proteins or other molecules but does not specifically measure the potency of active ingredients in the context of drug formulation.

SOP stands for Standard Operating Procedure, which provides guidelines for consistent performance of specific tasks within an organization, but it does not measure or quantify active ingredients. Therefore, potency assays are the appropriate choice for understanding the specific measurement of active drug content.