Ribavirin (known under brand names such as Rebetol, Copegus, Ribasphere and Virazole) is an analog of guanosine and a synthetic nucleoside antiviral agent. It is a stable, white crystalline compound with a maximum solubility in water of 142 mg/mL at 25°C and only a slight solubility in alcohol. Its empirical formula is C8H12N4O5 and the