PSI 7409 PSI7409 PSI-7409 (2R,3R,4R,5R)-5-(2,4-dioxopyrimidin-1-yl)-4-fluoro-3-hydroxy-4-methyloxolan-2-yl]methoxy-hydroxyphosphoryl] phosphono hydrogen phosphate Uridine 5'-(tetrahydrogen triphosphate), 2'-deoxy-2'-fluoro-2'-methyl-, (2'R)- sofosbuvir 5‘ - triphosphate Remdesivir Impurity 51