Simple and sensitive method for quantification of fludarabine triphosphate intracellular concentration in leukemic cells using isocratic liquid chromatography.

A simple, isocratic HPLC method was newly developed for quantitating intracellular fludarabine triphosphate (F-ara-ATP). Samples (500 microl) were injected onto an anion-exchange column and eluted isocratically with phosphate-acetonitrile buffer (flow rate: 0.7 ml/min) at an ambient temperature. F-ara-ATP was quantitated according to its peak area at the absorbance of 261 nm. The standard curve was linear with minimal within-day and inter-day variability. The low and high quantification limits were 50 pmol and 20 nmol, respectively. The method was capable of measuring F-ara-ATP generated in cultured leukemic cells in vitro. Thus, our method will be useful because of its sensitivity and simplicity as well as applicability to biological materials.