Bioequivalence and Bioavailability Forum

Dear balakotu,

did you ever considered searching this forum?

We had this recently. See this thread
Look especially at the EXCEL add-in named DDSolver.
In the accompanying material to this add-in (which can be accessed online) there is a description of some of the alternative methods to the similarity factor f₂. Among them Tsongs method using the Mahalanobis distance, which is nearly identical to the description in the FDA guidance, also no reference is given in the guidance.

But beware of using EXCEL in such a difficult analysis. Remember Martin's mantra: "never never never never use excel for any statistical calculations". And beware of the results of the 90% CI's of the Mahalanobis distance.

I personally don't belief in that results of DDSolver.
But unfortunately I can't check or verify because the Visual basic code behind that Add-in is password protected.

Unfortunately I'm not aware of any other software doing that calculations.

Moreover the theory behind Tsongs method is criticised fundamentally here.