NHC-diphosphate is an active phosphorylated intracellular metabolite of β-d-N4-Hydroxycytidine (NHC) as a diphosphate form[1]. NHC is a pyrimidine ribonucleoside and behaves as a potent anti-virus agent. NHC effectively inhibits the replication of venezuelan equine encephalitis virus (VEEV), Chikungunya virus (CHIKV) and hepatitis C virus (HCV).