Bioequivalence and Bioavailability Forum • Reference-scaled Bioequivalence

AngusMcLean
★★

USA,
2014-03-28 18:48
(4064 d 16:15 ago)

Posting: # 12735
Views: 3,972

Reference-scaled Bioequivalence [RSABE / ABEL]

http://screencast.com/t/dAkRl2NyPwe

I am reading the review paper of Barbara Davit published in Pharm. Research 2013. I have a comprehension problem

See link ABOVE to view the equation towards the top of the page.
It is evident that when σWR=σ W0 then the BE limits are the usual ±Ln 1.25 ie. (1.25, 0.8)
I want to use the equation to evaluate an example of the implied limits when σWR>σ W0 and I selected an example from the paper of σWR =0.7565. σ W0 is set at 0.25 by the Agency.
I am having difficulty following this equation and implementing it. I try and evaluate the right hand side of the equation towards the top of the page in the link attached
Ln (1.25) σWR/σ W0
As I read this equation I am thinking it is Ln(1.25)0.7565/0.25 =0.223*0.7565/0.25 = 0.6747
Or is it in the LN scale
Ln[(1.25) σWR/σ W0]= Ln 3.7825
Please can I be advised as to the evaluation of the right hand side of the equation; also I am interested how one arrives at the evaluation of the left hand side of the equation with the σWR and σ W0 is give.

Angus

d_labes
★★★

Berlin, Germany,
2014-03-31 13:16
(4061 d 22:47 ago)

@ AngusMcLean
Posting: # 12743
Views: 3,014

scABE - implied limits

Post reply

Dear Angus,

❝ I am reading the review paper of Barbara Davit published in Pharm. Research 2013. I have a comprehension problem ...

From time to time I also suffer from those symptoms :cool:

❝ ... Ln (1.25) σWR/σ W0

❝ As I read this equation I am thinking it is Ln(1.25)0.7565/0.25 =0.223*0.7565/0.25 = 0.6747

This is correct AFAIK with the exception
[nitpicking]log(1.25)*0.7565/0.25=0.6752324[/nitpicking] :-D

But the implied limits (lower limit is -0.6752324) are in the log domain. To obtain them in the original scale back-transform them

exp(-0.6752324)=0.5090381 (50.9%)

exp( 0.6752324)=1.964489 (196.4%)

—
Regards,

Detlew