Question

In a 3-point bioassay, the main purpose is to:

• A. Determine \(\text{LD}_{50}\)
• B. Compare potency of test and standard drug
• C. Determine \(\text{ED}_{50}\)
• D. Measure toxicity

Hint:

Bioassay Layouts: - 3-point: Uses 2 Standard doses + 1 Test dose. - 4-point: Uses 2 Standard doses + 2 Test doses. - Core objective: Calculate relative potency by comparing the test response directly to the standard reference curve.

Answer 1

The Correct Option is B

Concept: A bioassay (biological assay) is an experimental method used to estimate the potency of a substance by comparing its biological effect on living tissues or organisms against a reference standard. In a quantatative 3-point bioassay:
• The protocol uses two known concentrations of the standard reference drug ($S_1$ and $S_2$) and one concentration of the unknown test drug ($T$).
• It assumes that the log dose-response relationship is linear across the chosen dose range.
• The response of the single test dose ($T$) is interpolated along the standard dose-response line to calculate the relative potency of the test sample.

Step 1: Determine the primary purpose of the bioassay.
The fundamental purpose of multi-point parallel line bioassays (including 3-point and 4-point designs) is to compare the potency of a test drug against a standard reference drug, ensuring accurate formulation strength and standardization. It is not designed to measure overall population dynamics like $LD_{50}$ or $ED_{50}$.