Prodrug This invention relates to a prodrug of the monophosphate nucleotide of the well known oncology drug gemcitabine. Specifically it relates to gemcitabine [phenyl benzoxy L alaninyl)] phosphate when present as a single phosphate diastereoisomer and in particular it relates to the (S) phosphate diastereoisomerwhich offers a remarkable and unexpected increase in solubility relative to the (R) diastereoisomer. The (S) phosphate epimer is also preferentially taken up into cyclodextrin solutions over the (R) diastereoisomer.
