Achiral and chiral high-performance liquid chromatographic methods for clinafloxacin, a fluoroquinolone antibacterial, in human plasma.

Achiral and chiral HPLC methods were developed for clinafloxacin, a quinolone antimicrobial agent. For achiral assay, analytes were isolated from plasma by precipitating plasma proteins. Separation was achieved on a C18 column using an isocratic eluent of ion pairing solution-acetonitrile (80:20, v/v) at 1.0 ml/min with UV detection at 340 nm. The ion pairing solution was 0.05 M citric acid, 1.15 mM tetrabutylammonium hydroxide and 0.1% ammonium perchlorate. Inter-assay accuracy was within 4.9% with an inter-assay precision of 3.7% over a quantitation range of 0.025 to 10.0 microg/ml. For chiral assay, analytes were isolated from plasma by solid-phase extraction. Separation was achieved on a Crownpak CR(+) column using an isocratic eluent of water-methanol (88:12, v/v) containing 0.1 mM decylamine at 1.0 ml/min with UV detection at 340 nm. Perchloric acid was added to adjust pH to 2. Inter-assay accuracy was within 3.5% with a inter-assay precision of 5.4% over a quantitation range of 0.040 to 2.5 microg/ml.