Tenofovir exalidex (CMX157) is an investigational lipophilic prodrug of tenofovir, developed primarily for HBV infections with potent activity against HIV. It enhances delivery and efficacy by improving absorption, cellular uptake into lymphocytes and hepatocytes, and achieving higher intracellular tenofovir levels while reducing side effects and dosing frequency. This specialty research chemical (≥98% purity) targets viral replication and is used in antiviral studies, prodrug development, and investigations of drug resistance.