Bioequivalence and Bioavailability Forum

Dear All,

I would like to have your opinion on the unequal washout period in the following situations:

1. Four period study with no groups
   
2. Two or four period study with multiple groups (2 or 3 groups)

Should there be any concern from regulatory point of view (or statistical concern) if we maintain unequal washout period (but within protocol requirements) between different periods of same study or for different groups of the same study?

As far as I am concern it is immaterial, if we are maintaining sufficient washout period to ensure no carry­over effect, your views will be highly appreciated. From the forum I realized that Thai FDA may have concern as it has been mentioned in their guideline to maintain equal washout period between groups? Is there any scientific reason apart from consistency/ standardization?

Best Regards,

Ratnakar