Bioequivalence and Bioavailability Forum

Dear All

I am planning a BE study of Bicalutamide 150 mg tablet. The two (R) & (S) - enantiomers of Bicalutamide have different pharmacokinetics. Tmax of active (R)- enantiomer is 15-48 hr and that of inactive (S)- enantiomer is 2-5 hr. T1/2 of active (R)- enantiomer is about 1 week and that of (S)- enantiomer is 19 hr.

The study has been planned with the parallel truncated design upto 72 hrs and time points for blood sample collection are 0.00, 1.00, 2.00, 3.00, 4.00, 5.00, 6.00, 8.00, 12.00, 14.00, 15.00, 16.00, 18.00, 24.00, 28.00, 32.00, 36.00, 40.00, 44.00, 46.00, 48.00, 50.00, 60.00 and 72.00.

Please suggest:

1. Should we measure the racemate Bicalutamide or perform an enantiomer specific assay (i.e. active (R)- enantiomer)?
   
2. Is the study design ok and are the time points selected for blood sample collection appropriate so as to capture the real Cmax?
   
3. Is the 150 mg dose is safe in healthy human subjects?
   
4. What should be the sample size?

Regards
Dr Muneesh Garg