A bioequivalence study is a clinical study that forms the basis for the approval of a generic product. In accordance with the provisions of the German Medicines Act, it is proven that the generic product as the test product and the reference product are bioequivalent. The analysis focuses on how quickly and to what extent the active ingredient is absorbed in the human circulation. This allows conclusions to be drawn about the bioavailability of the active ingredient in the body. As a rule, bioequivalence studies are carried out on at least 20-30 subjects. The study is conducted in three phases:
- Phase 1: Subjects receive the generic drug to test efficacy and side effects.
- Phase 2: The elimination phase can extend over several days to weeks depending on the half-life of the preparation. This is to asure that there are no traces of the substance in the body.
- Phase 3: In the third phase, the same subjects receive a reference product to test whether the same efficacy and side effects occur as with the previous generic product
Blood samples are taken regularly during the various phases, yielding information on plasma levels and active metabolites. For a bioequivalence study, three parameters are of particular importance: the extent of bioavailability, the maximum plasma concentration, and the rate of release and absorption of the drug.