What laboratory procedure is used to measure how many active ingredient molecules are present in a drug formulation?

A potency assay is a laboratory procedure designed to determine the effectiveness of a drug by measuring how many active ingredient molecules are present in a drug formulation. This assay evaluates the biological activity of the drug, often in relation to its concentration, and helps in understanding how much of the active ingredient is required to achieve a desired effect in a biological system.

Potency assays are crucial in drug development and regulatory processes as they ensure that the formulation will provide the intended therapeutic effect. By quantifying the active substances, these assays enable scientists and manufacturers to confirm that their products meet required specifications for efficacy before they reach the market.

In contrast, while the other procedures may focus on different aspects, they do not specifically quantify the active ingredient in the same way. Activity assays generally assess the biological response produced by a compound but don't directly measure the quantity of active molecules. Concentration assays focus on measuring the ratio or amount of a substance in a mixture but may not directly relate to biological activity. Stability assays evaluate the drug's effectiveness over time under different conditions, but they do not quantify the initial amount of active ingredients present.