Ribavirin- 13 C 5 is the 13 C-labeled Ribavirin. Ribavirin (ICN-1229) is an antiviral agent against a broad spectrum of viruses including HCV , HIVl, and RSV . In Vitro Stable heavy isotopes of hydrogen, carbon, and other elements have been incorporated into drug molecules, largely as tracers for quantitation during the drug development process. Deuteration has gained attention because of its potential to affect the pharmacokinetic and metabolic profiles of drugs. MCE has not independently confirmed the accuracy of these methods. They are for reference only.