A Comparative Study of Statistical Methods for Population Bioequivalence in 2 x 2 Crossover Design

The US Food and Drug Administration(FDA) recommends that population bioequivalence and individual bioequivalence would be assessed to address the prescribability and switchability between a brand-name drug and its new formulation or generic copy in its 2001 guidance document. The test for population bioequivalence in the latest FDA guidance is recommended in 2 x 4 crossover design, but it turns out to be very conservative. Recently Lee, Shao & Chow(2002), Chow, Shao & Wang(2003) and McNally, Iyer & Mathew(2002) proposed new statistical methods for assessing population bioequivalence between drugs to correct the biasness of current FDA method. Since 2 x 2 crossover experiment is most welcomed design in bioequivalence testing, we adopt their methods to 2 x 2 crossover designs and compare their methodologies with FDA one through the simulation study.