<p>Two drug products containing the same drug substance or substances are considered bioequivalent if their bioavailabilities (rate and extent of drug absorption) after administration in the same molar dose lie within acceptable predefined limits. These limits are set to ensure comparable in vivo performance, i.e., similarity in terms of safety and efficacy. In in vivo bioequivalence studies, the pivotal pharmacokinetic parameters area under the concentration time curve (AUC) and maximum concentration (Cmax), are generally used to assess the rate and extent of drug absorption.