The bioavailability of Tamoplex (tamoxifen). Part 4. A parallel study comparing Tamoplex and four batches of Nolvadex in healthy male volunteers.

A randomized parallel design has been validated for the study of tamoxifen bioavailability. Strong evidence was presented for the bioequivalence of Tamoplex 10 mg and four Nolvadex 10 mg preparations. Interbatch differences were of the same magnitude as differences between Tamoplex 10 mg and Nolvadex 10 mg. No in vitro--in vivo relationship could be established. Distribution and metabolism are the dominating factors in tamoxifen pharmacokinetics.