Institution: | a The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA b Berlex Biosciences, Alameda, CA, USA |
Abstract: | Rapid and quantitative dephosphorylation of the new anticancer nucleotide analogue fludarabine phosphate to its nucleoside 9-β-D-arabinofuranosyl-2-fIuoroadenine (F-ara-A) renders this metabolite the target for pharmacologic investigations. At clinically effective doses of fludarabine phosphate (18–30 mg/m2 per day) comprehensive pharmacokinetic analysis of F-ara-A has been limited by the sensitivity of UV based HPLC assays. To address this problem we developed a sensitive test based on the condensation of F-ara-A with chloroacetaldehyde to form the fluorescent derivative, arabinosyl-1, N6-etheno-isoguanine. Combined with a solid-phase extraction step prior to derivatization and separation of the reaction products by reverse-phase HPLC, this assay had a quantitation limit of 2 pmol F-ara-A per ml plasma. Slightly modified, the system was also applicable to urine specimens, with a quantitation limit of 1 nmol F-ara-A per ml urine. |