Bioequivalence and Bioavailability Forum

dear sasikumar!

this guideline may help in understanding the different concepts of testing for equivalence/non-inferiority and testing for difference/superiority: http://www.tga.gov.au/docs/pdf/euguide/ewp/048299en.pdf

testing for equivalence with a type I error of 5% can be done by the two-sided 90% confidence interval inclusion approach (similar to the two one-sided tests approach TOST). the calculated two-sided 90% confidence interval for the difference between test and reference treatment (e.g. ratio of geometric means) must fall completely within pre-specified margins of equivalence. conventional margins in pharmacokinetics are 0.8 to 1.25 which are symmetric margins for ratios as 1/0.8=1.25 and 1/1.25=0.8.

for more detail regarding testing for equivalence you may find this book helpful: Wellek S (2003). Testing Statistical Hypotheses of Equivalence. Chapman and Hall/CRC Press.

best regards

martin