Abstract
A sensitive, specific and efficient high-performance liquid chromatography/tandem mass spectrometry assay for the simultaneous determination of vinorelbine and its metabolite 4-O-deacetylvinorelbine in human and mouse plasma is presented. Heated electrospray ionization was applied followed by tandem mass spectrometry. A 50 microL plasma aliquot was protein precipitated with acetonitrile-methanol (1:1, v/v) containing the internal standard vinorelbine-d3 and 20 microL volumes were injected onto the HPLC system. Separation was achieved on a 50 x 2.1 mm i.d. Xbridge C(18) column using isocratic elution with 1 mm ammonium acetate-ammonia buffer pH 10.5-acetonitrile-methanol (28:12:60, v/v/v) at a flow rate of 0.4 mL/min. The HPLC run time was 5 min. The assay quantifies both vinorelbine and 4-O-deacetylvinorelbine from 0.1 to 100 ng/mL using sample volumes of only 50 microL. Mouse plasma samples can be quantified using calibration curves prepared in human plasma. Validation results demonstrate that vinorelbine and 4-O-deacetylvinorelbine can be accurately and precisely quantified in human and mouse plasma with the presented method. The assay is now in use to support (pre-)clinical pharmacologic studies with vinorelbine in humans and mice.