Bioequivalence and Bioavailability Forum

I have a FDC and a drug-drug interaction study is planned.

For DDI studies I have some doubt regarding study design.

1) What kind of design would be better (and why?).
A 6x3 design or perform 2 studies 2x2?


2) In this FDC I have 1 active substance as prolonged release formulation. Do I have to perform this study in a fast and fed conditions? This applies for DDI study?

3) The outcomes are listed below. There is any other possible outcome for this kind of study?

• Inducer: if the upper limit of the CI is less than 70%;
• No interaction: if the lower limit of the CI is greate/equalr than 80% and the upper limit equal/less than 125%;
• Weak interaction or weak inhibition: if the lower limit of the CI is higher than 125% and the upper limit is equal/less than 200%;
• Moderate interaction or moderate inhibition: if the lower limit of the CI is higher than 200% and the upper limit is equal/less than 500%;
• Strong interaction or strong inhibition: if the lower limit of the CI is higher than 500%.


Thanks for the help!