What is the Origin of Potency Assays?

The concept of potency derives from pharmacology, where it contrasts with affinity, focusing on the magnitude of the response produced by a given dose. These assays evolved from early animal bioassays to modern cell-based reporter gene assays that measure receptor activation with high sensitivity. Their origin is the need to ensure therapeutic products deliver a predictable biological impact.

What is the Mechanism of Potency Assays?

A typical mechanism involves exposing responsive target cells (e.g., cells expressing the androgen receptor) to serial dilutions of the test substance and measuring a downstream biological marker, such as proliferation or gene transcription, often reported as an $text{EC}_{50}$ value. This value represents the concentration needed to achieve 50% of the maximal effect, providing a quantifiable metric of the substance's biological strength relative to a reference standard.

Potency Assays

Meaning

Potency Assays are standardized in vitro or in vivo bioassays designed to quantitatively measure the biological activity or effective concentration of a hormone or a hormone-like substance required to elicit a specific physiological response. These assays are fundamental for determining the relative strength of pharmaceutical preparations, especially for bioidentical hormones or novel receptor agonists. Precision in these measurements directly impacts dosing recommendations in clinical endocrinology.