A validated LC-MS/MS method for the determination of vinflunine in plasma and its application to pharmacokinetic studies.

A rapid, simple and sensitive LC-MS/MS method for the quantification of vinflunine in plasma was developed and validated. The analysis involved a simple liquid-liquid extraction. After making alkaline with NaOH, plasma was extracted with methyl tert-butyl ether and the organic extract was then evaporated and the residue was reconstituted in mobile phase. The reconstituted solution was injected into an HPLC system and was subjected to reverse-phase HPLC on a 5 µm ODS-3 column at a flow-rate of 0.2 mL/min. The mobile phase consisted of ammonium acetate (0.02 mol/L, pH = 3.0) and acetonitrile (20:80). Vinflunine was detected in the single ion monitoring mode using target ions at m/z 817.4/160.1/142.3 for vinflunine and m/z 447.2/128.3/112.1 for gefitinib (internal standard). Standard curves were linear over the concentration range of 5-1000 ng/mL. The mean predicted concentrations of the quality control samples deviated by less than 2% from the corresponding nominal values; the intra-assay and inter-assay precisions of the assay were within 7% relative standard deviation. The extraction recovery of vinflunine was more than 80%. The validated assay was applied to a pharmacokinetic study of vinflunine in plasma following the administration of a single vinflunine injection (2 mg/kg).