Are 5'-O-carbamate-2',3'-dideoxythiacytidine new anti-HIV and anti-HBV nucleoside drugs or prodrugs?

Abstract In contrast to 5′- O -carbonate 3TC derivatives ( 23 , 24 ), which are clearly 3TC prodrugs, the corresponding 3TC carbamates ( 15 – 21 and 25 ), found to be very stable compounds with respect to enzymatic hydrolysis (cellular lysates and culture cell media) and still active on both HIV-1 and HBV infected cells, may not be 3TC prodrugs. The antiviral properties as well as the mechanism of action of 3TC analogues have been studied and evaluated.