Application of moment analysis in assessing rates of absorption for bioequivalency studies.

Moment analysis was utilized in the evaluation of equivalency between test and reference formulations with respect to the rate of absorption for four drugs having different pharmacokinetic characteristics. A confidence interval technique was applied to compare the three relevant absorption parameters, that is, peak plasma concentration (Cmax), time to peak plasma concentration (tmax), and mean absorption time (MAT). Equivalence in the absorption rate of drugs was found to be best evaluated by the combined use of MAT, tmax, and Cmax. Use of these parameters for assessing equivalency requires careful interpretation of the results of statistical analysis as well as appropriate consideration of efficacy and safety issues for individual drugs. In addition, the statistical moment method proves to be useful in the assessment of bioequivalency, particularly for drugs with multiple absorption maxima.