Rapid determination of gemifloxacin in human plasma by high-performance liquid chromatography-tandem mass spectrometry.
A method was developed for the determination of gemifloxacin (I) in human plasma using high-performance liquid chromatography-tandem mass spectrometry. Prior to analysis, the protein in plasma samples was precipitated with acetonitrile containing [13C2H3] gemifloxacin (II) to act as an internal standard. The supernatant was injected onto a PLRP-S column without any further clean-up. The mass spectrometer was operated in positive ion mode, employing a heat assisted nebulisation. electrospray interface. Ions were detected in multiple reaction monitoring (MRM) mode. The assay requires 50 microl of plasma and is precise and accurate within the range 10-5,000 ng/ml. The average within-run and between-run coefficients of variation were <11% at 10 ng/ml and greater concentrations. The average accuracy of validation standards was generally within +/-7% of the nominal concentration. There was no evidence of instability of I in human plasma following three complete freeze-thaw cycles and samples can safely be stored for at least 6 months at -20 degrees C. The method proved very robust and was successfully applied to the analysis of clinical samples from patients dosed with gemifloxacin.
Doyle
E
E
Department of Drug Analysis, SmithKline Beecham Pharmaceuticals, Welwyn, Hertfordshire, UK.
Fowles
S E
SE
McDonnell
D F
DF
McCarthy
R
R
White
S A
SA
D000890:Anti-Infective Agents / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D024841:Fluoroquinolones; D000077735:Gemifloxacin; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D009287:Naphthyridines / Q000097:blood*; D015203:Reproducibility of Results
D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D009287:Naphthyridines; D000077735:Gemifloxacin