PSI-7977-13C-d3 is intended for use as an internal standard for the quantification of PSI-7977 by GC- or LC-MS. PSI-7977 is a phosphoramidate prodrug of PSI-7851, a nucleoside analog that, when phosphorylated, inhibits the RNA-dependent RNA polymerase of hepatitis C virus (EC50 = 92 nM). PSI-7977 is effective in vitro and in vivo.
