Module 9 2024

03/09/2024

Measurements in Bioassays - Variation of Effective Dose @ 50%

response

Concentration

ED 50

Example: ED 50 of JNIH-5 pertussis toxin in CHO cell assay: varied approx. 150-fold across assays in a multi-lab study (Xing et al, Vaccine 20 (2002) 3535)

Absolute potency results are not used routinely due to the high variability between assays.

The Organisation for Professionals in Regulatory Affairs

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Measurements in Bioassays

• Activity of a new batch of therapeutic measured against a defined Reference standard material

std

std

unk

unk

• If the new batch and reference are sufficiently similar, variations in the assay system affect them both and therefore quantification of the unknown is measured against the reference, resulting in Relative Potency.

The Organisation for Professionals in Regulatory Affairs

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