What is the Difference Between Assay and Potency?

The main difference between assay and potency lies in their definitions and applications in pharmacology and biochemistry:

• Assay: An assay is a testing procedure used to determine the ingredients and quality of a material, such as a biological sample or a drug. It involves sample preparation, discrimination, amplification, and analysis. Assay can be calculated in three different ways: on as-is basis, on dried basis, and on an anhydrous basis.
• Potency: Potency refers to the effectiveness of a drug, measured as the amount required to produce a specific effect. It is calculated by finding the half-maximal effect concentration of the drug. Potency takes into account factors such as impurities, residual solvents, sulfated ash, heavy metals, and water content. The formula for potency is: 100 - (%Imp. + RSL + Sulfated ash + Heavy metal + LOD or Water content).

In summary, an assay is a test used to identify and quantify components in a sample, while potency is a measure of a drug's effectiveness based on the amount needed to produce a specific effect.

Comparative Table: Assay vs Potency

Here is a table highlighting the differences between assay and potency:

Both assay and potency are used to determine the concentration and activity of a substance, such as a drug, but they differ in their approaches and calculations. Assay focuses on the concentration of a substance, while potency measures the activity of a substance relative to a standard.