What Are Bioequivalence Studies?

By John Pezzullo

A bioequivalence study is usually a fairly simple pharmacokinetic study, having either a parallel or a crossover design. You may be making a generic drug to compete with a brand-name drug already on the market whose patent has expired. The generic and brand-name drug are the exact same chemical, so it may not seem reasonable to have to go through the entire drug development process for a generic drug.

But because there are differences in the other ingredients that go into the drug (such as fillers and coatings), you have to show that your formula is essentially bioequivalent to the name-brand drug. Bioequivalent means that your generic product puts the same (or nearly the same) amount of the drug’s active ingredient into the blood as the brand-name product.

Each subject is given a dose of the product (either the brand-name or generic drug), and blood samples are drawn at carefully chosen time points and analyzed for drug concentration. From this data, the basic PK parameters (AUC, CMax, and so on) are calculated and compared between the brand-name and generic versions.