Detection and determination of the major metabolites of [3H]cytosine arabinoside by high-performance liquid chromatography.

An ion-pair high-performance liquid chromatographic assay involving solid-phase scintillation detection was established for the rapid identification and determination of all major metabolites of tritium-labelled cytosine arabinoside (Ara-C) in an in vitro system. In a single run of 50 min, Ara-C, Ara-CMP, Ara-CDP-choline, Ara-CDP, Ara-U, Ara-UMP, Ara-CTP, Ara-UDP and Ara-UTP can be measured. The method is fast, sensitive, with limits of detection ranging from 40 to 200 pg (absolute), and highly reproducible.