A validated HPLC-MS/MS method for the quantification of caderofloxacin in human plasma and its application to a...

A simple, selective and rapid HPLC-MS/MS method was developed and validated for the determination of caderofloxacin in human plasma. Sparfloxacin was used as the internal standard (IS). After precipitation with methanol and dilution with the mobile phase, the samples were injected into the HPLC-MS/MS system. The chromatographic separation was performed on a Zorbax XDB Eclipse C18 column (150 × 4.6 mm, 5 µm) with a mobile phase of ammonium acetate buffer (20 mm, pH 3.0)-methanol, 45:55 (v/v). The MS/MS analysis was done in positive mode. The multiple reaction monitoring transitions monitored were m/z 412.3 → 297.1 for caderofloxacin and m/z 393.2 → 292.2 for the IS. The calibration curve was linear over the range of 50.0-8000 ng/mL with an aliquot of 100 μL plasma. The precision of the assay was 2.0-9.4 and 6.6-11.5% for the intra- and inter-run variability, respectively. The intra- and inter-run accuracy (relative error) was 4.4-10.0 and -1.2-4.0%. The total run time was 3.5 min. The assay was fully validated in accordance with the US Food and Drug Administration guidance. It was successfully applied to a pharmacokinetic study of caderofloxacin in healthy Chinese volunteers.