Adefovir is a medication used to treat chronic hepatitis B infection. Stable isotopes of Adefovir are non-radioactive isotopes that have the same chemical properties as the radioactive isotopes of Adefovir. These stable isotopes are used in research and development activities to study the metabolism, pharmacokinetics, and drug interactions of Adefovir. They provide a safe and cost-effective alternative to radioactive isotopes.