Relative response factor: the ratio of the response factor of individual related

substance to that of a drug substance to correct for differences in the response

of related substances and that of the drug substance. It can be determined

using the following equation:

Relative response factor =

response factor of individual related substance

response factor of drug substance

If a linearity curve (Figure 3.1) is constructed for both the related substance

and the drug substance by plotting the response versus the concentration,

the relative response factor can also be determined by

Relative response factor =

slope

related substance

slope

drug substance