Determination of desoxyepothilone B in nude mice plasma by liquid–liquid extraction and reversed-phase high-performance liquid chromatography

A novel reversed-phase high-performance liquid chromatographic (HPLC) method has been established for the determination of a newly developed anti-cancer agent desoxyepothilone B (dEpo B) in nude mice plasma. The sample preparation involved deproteination of 200 μl of plasma sample first, followed by liquid–liquid extraction of the resultant supernatant with chloroform. The compound taxol was used as the internal standard. Chromatographic separations were carried out on a 250 mm × 4.6 mm Zorbax SB-phenyl column with acetonitrile–0.25% orthophosphoric acid (50/50, v/v) as mobile phase and UV detection at 250 nm. For dEpo B and taxol at the concentration level of 10 μg/ml in nude mice plasma, the absolute extraction recoveries were 85.3 and 87.2%, respectively. The linear quantification range of the method was 0.1–100 μg/ml in nude mice plasma with linear correlation coefficients greater than 0.999. The within-day and between-day relative standard deviations (R.S.D.s) for dEpo B at 0.5, 2.5 and 10 μg/ml levels in nude mice plasma fell in the range of 2.8–4.8 and 1.5–4.6%, and the within-day and between-day recoveries were in the range of 96.5–101.7 and 97.7–101.2%, respectively.