5'-phosphonate derivatives of 2',3'-dideoxy-3'-thiacytidine as new anti-HIV prodrugs.

Two new phosphonate 3TC prodrugs were synthesized and studied in MT-4 cells as inhibitors of HIV replication. Their pharmacokinetic parameters were evaluated following intragastric administration in rabbits and oral administration in dogs. Both compounds were much less toxic than parent 3TC in cell cultures and could generate the active nucleoside in laboratory animals.