GS-443902 trisodium (GS-441524 triphosphate trisodium) is a potent viral RNA-dependent RNA-polymerases (RdRp) inhibitor with IC 50 s of 1.1 µM, 5 µM for RSV RdRp and HCV RdRp, respectively. GS-443902 trisodium is the active triphosphate metabolite of Remdesivir (GS-5734) In Vitro In a continuous 72 h incubation of 1 µM Remdesivir (GS-5734), the GS-443902 trisodium (GS-441524 triphosphate trisodium; Remdesivir metabolite trisodium) level is measured at 2, 24, 48 and 72 h, and reaches a C max of 300, 110, and 90 pmol/million cells in macrophages, HMVEC, and HeLa cells lines respectively. GS-443902 trisodium (compound 8a) is a triphosphates (TP) derivative. GS-443902 trisodium (NTP; 0.01, 0.1, 1, 10, 100 μM) inhibits RSV RdRp-catalysed RNA synthesis by incorporating into the nascent viral RNA transcript and causing its premature termination. GS-5734 selectively inhibits EBOV replication by targeting its RdRp and inhibiting viral RNA synthesis following efficient intracellular conversion to GS-443902 sodium. MCE has not independently confirmed the accuracy of these methods. They are for reference only. In Vivo Remdesivir (GS-5734; 10 mg kg; i.v.) rapidly distributes into peripheral blood mononuclear cells (PBMCs), and efficient conversion to GS-443902 trisodium (Remdesivir metabolite trisodium; NTP) is apparent within 2 h of dose administration in rhesus monkeys. In PBMCs, GS-443902 trisodium represents the predominant metabolite and is persistent with a t 1/2 of 14 h and levels required for >50% virus inhibition for 24 hours. MCE has not independently confirmed the accuracy of these methods. They are for reference only. Form:Solid IC50& Target:IC50: 1.1 µM (RSV RdRp) and 5 µM (HCV RdRp)