Determination of vinflunine in Beagle dog's plasma b LC-MS and study of its pharmacokinetics

Aim: To develop a method for the quantification of vinflunine in Beagle dog's plasma by LC-MS, and to examine pharmacokinetic characteristics of vinflunine in Beagle dogs. Methods: After being spiked with finasteride as internal standard and alkalization by 0.25 mol/L NaOH, plasma was extracted by ethyl acetate. The organic layer was evaporated and reconstituted with mobile phase. Analysis of plasma was carried out on a Shimadzu VP-ODS column (150 mm × 4.6 mm ID, packed with 5 μm C₁₈ silica RP particle). The mobile phase was consisted of methanol-10 mmol/L ammonium acetate buffer (80:20) with the flow rate of 1.0 mL/min. LC-MS was performed in the selected ion monitoring (SIM) mode with target ions at m/z: 817.3 for vinflunine and m/z: 373.2 for finasteride. Results: Calibration plots for vinflunine related to internal standard, finasteride, were linear over the concentration range of 0.025-12.5 μg/ mL. The variability values of intra-assay and inter-assay were both less than 7.8%. The relative recovery of vinflunine from plasma was in the range of 97.0%-100.2%. Conclusion: The established LC-MS method is simple, accurate, sensitive and applicable for pharmacokinetic study of vinflunine in dogs.