**4.1 Universal approach about comparative bioavailability**

Most bioavailability studies, whether for a new or generic product, are carried out for the common theme. These studies are conducted to identify the quantitative nature of a specific product comparison. The absolute bioavailability of new drug is used to assess the pharmacokinetic parameters of an oral formulation relative to that of an intravenous dose or performance of a modified release formulation in comparison to a conventional capsule. For a generic product, it is mainly done for comparison of a competitive formulation with a reference or standard drug. Such commonality in comparative bioavailability studies suggests a universal experimental approach.
