Bioequivalence and Bioavailability Forum

We are facing a complicated issue: we are planning a PK pilot study for a DPI (dry powder inhaler). Due to budget issues we can perform the trial with only 8 volunteers.
The reference formulation is an association of two different capsules (formoterol + budesonide).
Our primary endpoints are: 1- to observe the influence of a charcoal blockade, 2- to determine n for a regulatory study (although in Brazil there is not a particular regulatory resolution regarding this kind of inhalator pharmaceutics' forms) and 3- to preliminary evaluate the behavior of the test formulation/device.
We have then, 2 formulations (test and reference) and 2 conditions to administer the drugs (with and without charcoal blockade).
Consequently, we can't approach the trial as the classical R vs T1, T2 and T3 situation.
Our first choice was to run a two sequences, 4 period trial, i.e., Tc, Tn, Rc, Rn (T: test formulation, R: reference formulation, c: charcoal, n: no charcoal) and Rn, Rc, Tn, Tc.

However, our consultant statistician suggested a double replicate no-crossover (for test and reference):

1st. sequence: Rc, Rc, Rn, Rn
2a. sequencia: Tc, Tc, Tn, Tn
Suggestions and comments are very welcome.

Thanks to all

Carlos Sverdloff
carsver "AT" yahoo.com.br
Synchrophar Clinical Trials - Brazil

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