title: High-performance liquid chromatographic procedures for the determination of difloxacin and its metabolites in biological matrices.
abstract: A simple and extremely precise high-performance liquid chromatographic procedure has been developed for the determination of difloxacin and its metabolites in plasma and urine. Work-up of plasma samples entails ultrafiltration after addition of an internal standard in a displacing reagent containing sodium dodecyl sulfate. The ultrafiltrates are directly analyzed using a C18 reversed-phase analytical column, a soap-chromatographic mobile phase, and a fluorescence or ultraviolet detector. The mean intra-assay coefficient of variation for difloxacin over a concentration range of 10 ng/ml to 10 micrograms/ml was 0.5% when fluorescence detection and an internal standard were employed. Inter-assay coefficients of variation were approximately 2%. Recoveries of difloxacin and its metabolites were essentially quantitative and calibration curves were strictly rectilinear.
mesh_terms: D000890:Anti-Infective Agents / Q000032:analysis* / Q000097:blood / Q000652:urine; D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid; D002939:Ciprofloxacin / Q000031:analogs & derivatives* / Q000032:analysis / Q000097:blood / Q000652:urine; D024841:Fluoroquinolones; D006801:Humans; D007700:Kinetics; D010084:Oxidation-Reduction; D014462:Ultrafiltration
chemical_list: D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D002939:Ciprofloxacin; C047225:difloxacin