What Is a Generic Drug?

Generic Drug

Generic drugs are typically small, chemically synthesized molecules—that is, they have relatively low molecular weights, frequently less than 1000 daltons and usually between 300 and 700 daltons. Biosimilars, on the other hand, are typically substantially larger in molecular weight than small molecule drugs. For example, a monoclonal antibody—a typical biosimilar drug—generally has a molecular weight in excess of 150,000 daltons. In contrast, aspirin—a typical small molecule drug—has a molecular weight of 180 daltons.