Bioequivalence and Bioavailability Forum

Hi ammulu,

❝ Hi guys can any one tell me why we should log transform the data for

❝ calculations of BA-BE data?

1. Because regulators want you to.
2. Because the model used for evaluation assumes that the residuals of the model fit follow a normal distribution, and log transformation is "widely" believed to make that assumption justified in "most cases".
2½. Because AUC and Cmax-values cannot be negative, there is a restriction on the residuals if you use a non-transformed evaluation. That restriction is in contradiction with the prinicple of normality.

❝ whether natural log should be used or any other ?

Doesn't matter. Your result will be the same. Try and see for yourself.

EM.