A method and composition for the treatment of HIV and HBV infections in
humans is disclosed that includes administering an effective amount of
2-hydroxymethyl-5-(5-fluorocytosin-1-yl)-1,3-oxathiolane, a
pharmaceutically acceptable derivative thereof, including a 5' or N.sup.4
alkylated or acylated derivative, or a pharmaceutically acceptable salt
thereof, in a pharmaceutically acceptable carrier.A process for the
resolution of a racemic mixture of nucleoside enantiomers is also
disclosed that includes the step of exposing the racemic mixture to an
enzyme that preferentially catalyzes a reaction in one of the
enantiomers.