ent-Emtricitabine Triphosphate Triethylammonium Salt is a metabolite of ent-Emtricitabine (E525005). The free acid, ent-Emtricitabine Triphosphate inhibits the prodn. of full-length minus-strand DNA in an endogenous reverse transcriptase reaction, inhibits DNA synthesis, and can be used as a chain-terminating substrate.