Bioequivalence and Bioavailability Forum

Dear All,

I would like to discuss some issues in FDC studies design.
For examle, we have FDC with 2 APIs. Let's say we know that no PK interaction is expected and the intraCVs in the pilot study were similar to the single dosage forms.
If we calculate the sample size for the first API (ABC) and the second API (XYZ) with a power 80%, we'll get some values.
So... We have only 80% of probability to prove BEQ for ABC (20% of II type error) and 80% for XYZ.
Final probability is 80%*80%=64%!
Should we use another power for calculations (89%*89%=80%)?

Can someone correct or comment my statistical calculations?
What about triple FDC (92.8%*92.8%*92.8%=80%)?