A New High-performance Liquid Chromatographic Method for Fludarabine and Fludarabine Phosphate Compounded in
Abstract:
A simple and reproducible high-pressure liquid chromatography (HPLC) method was developed to measure simultaneously the concentrations of both fludarabine and liposome-compounded fludarabine in plasma. In this method, hypoxanthine 9-B-D arabinofuranoside was used as an internal standard. Fludarabine, fludarabine phosphate, and hypoxanthine 9-B-D arabinofuranoside were extracted from plasma and were separated by means of isocratic elution from a C18 reversed-phase column. The mobile phase consisted of 5% (v/v) methanol in 10mM ammonium phosphate solution. The pH of the mobile phase was adjusted to 2.2 with 85% phosphoric acid. The detection wavelength was 260 nm, and the retention times for fludarabine, fludarabine phosphate, and hypoxanthine 9-B-D arabinofuranoside were 48, 27, and 12 minutes, respectively. The recovery efficiencies varied depending on the amount spiked; however, they were 89% and 58% for 10 micrograms/mL of fludarabine and fludarabine phosphate, respectively. The limits of quantification for fludarabine and fludarabine phosphate were 0.03 micrograms/mL and 0.5 micrograms/mL, respectively. The assay was reproducible, and the within-day coefficients of variation (n=4) were less than 6.9% and less than 8.7% for fludarabine and fludarabine phosphate, respectively. The between day variabilities (n=4) were less than 6.3% and less then 6.4% for fludarabine and fludarabine phophate, respecitvley. The assays were linear within the range of 0.025 to 10 micrograms/mL (r squared = 0.999) for fludarabine and 0.5 to 10 micrograms/mL (r squared = 0.999) for fludarabine phosphate.
