Determination concentration of paclitaxel by RP-HPLC in mice plasma

Objective To establish a method to determine the concentration of paclitaxel in mice plasma by reverse phase high-performance liquid chromatography.Methods Solid-phase extraction procedure was developed to extract paclitaxel and docetaxel,which was the internal standard,and the plasma samples were analyzed on Waters Nova-park C18 column(4 μm,150 mm×3.9 mm),detected at 227 nm.The moble phase consisted of acetonitrile-H2O = 42∶58 at a flow rate of 1.0 mL·min-1.The pharmacokinetics of paclitaxel in mice after a single injection dose of 18 mg·kg-1 was studied.Results The retention times of paclitaxel and docetaxel were 10.3 min and 8.1 min,respectively.The standard curve was Y= 4 × 10-4X-4.4 × 10-3(γ= 0.9995)with a validated quantitation range of 50 ～ 3200 ng· mL-1,and the lowest concentration of detection in mice plasma was 12.5 ng· mL-1,which met the requirement of the whole examination.The absolute recovery rates were ranged from 101.82% to 106.98% and relative recovery rates were ranged from 94.3% to 108.1%.The RSD of the precision within-day and between-day was less than 6.0%.The concentration-time curve of paclitaxel was well fitted to a two-compartment model and the main pharmacokinetic parameters were as follows:t1/2α was(0.59 ± 0.03)h,t1/2β was(1.33 ± 0.09)h,AUC0→∞was(80.1 ± 3.20)h· μg· mL-1,Vd was(9.08 ± 0.51)mL.Conclusion The assay method is shown to be sensitive,suitable and accurate for determination of paclitaxel in mice plasma.