Optimal Unbiased Tests for Equivalence in Intrasubject Variability

The equivalence in average bioavailability between formulations may not be sufficient for assessment of bioequivalence. The difference in intrasubject variability between formulations should also be considered. This article presents an unbiased test procedure for equivalence in intrasubject variability of bioavailability that is uniformly more powerful than the two one-sided tests procedure proposed by Liu and Chow. Under a stronger condition, a uniformly most powerful invariant test for this problem is proposed. Some numerical comparisons and an example are also presented.