An alternative approach for assessment of rate of absorption in bioequivalence studies.

The partial area method was investigated for evaluation of equivalency in the rate of absorption of immediate release formulations. The applicability of the method was demonstrated with four drugs with different pharmacokinetic/pharmacodynamic characteristics. The confidence interval approach currently employed for bioequivalence determinations was applied to the relevant absorption parameters, including Cmax and partial AUCs. The method was found to be more discriminating than Cmax and/or Tmax in the evaluation of the absorption rate of drugs. The cutoff time or point for partial AUC calculation may vary with the type of drug under study, depending on its clinical use and onset of action. The method was shown to be useful in the assessment of rate of absorption in bioequivalence studies.