Bioequivalence and Bioavailability Forum

Hello,

We have conducted a randomized, sequential and crossover trial of two formulations for nasal inhalation in a pressurized container with 18 healthy volunteers. The test drug and the reference drug were administered both with and without inhalation chamber, which represents four experimental periods. Randomization of the form of administration was conducted (Test with chamber / Reference without chamber / Reference with chamber / Test without chamber), so that the 18 subjects completed the four periods.

The objective of the first stage was to obtain the necessary data to calculate the final sample size.

Once finished the first stage, the statistical analysis resulted on different CV intra for each form of administration with and without chamber, (29% and 35% respectively). So, finally 36 and 60 volunteers respectively should be added in in the second stage.

Would it be necessary to complete the second stage with 60 subjects for both forms of administration? or could we reduce to 36 subjects in the case of chamber?

Thanks,

Kind regards.