Studies of the Pharmacokinetics and Toxicology of 2',3'-Dideoxy-β-L-5-fluorocytidine (β-L-FddC) and 2',3'-Dideoxy-β-L-cytidine (β-L-ddC) In Vivo; and Synthesis and Antiviral Evaluations of 2',3'-Dideoxy-β-L-5-azacytidine
The pharmacokinetics and toxicology of 2',3'-dideoxy-beta-L-5-fluorocytidine (beta-L-FddC) and 2',3'-dideoxy-beta-L-cytidine (beta-L-ddC) in mice was investigated. In addition, 2',3'-dideoxy-beta-L-5-azacytidine (beta-L-5-aza-ddC) and its alpha-L-anomer (alpha-L-5-aza-ddC) were synthesized by coupling the silylated 5-azacytosine derivative with 1-O-acetyl-5-O-(tert-butyldimethyisilyl)-2,3-dideoxy-L-ribofuranose, followed by separation of the alpha- and beta-anomers and were evaluated in vitro against HBV and HIV. beta-L-5-aza-ddC was found to show significant anti-HBV activity at approximately the same level as 2',3'-dideoxy-beta-D-cytidine (ddC), which is a known anti-HBV agent. beta-L-5-aza-ddC was not cytotoxic to L1210, P388, S-180, and CCRF-CEM cells up to a concentration of 100 mu M. Conversely, the alpha-L-anomer was not active against HBV at the same concentration.