title: Simultaneous determination of danofloxacin and N-desmethyldanofloxacin in cattle and chicken edible tissues by liquid chromatography with fluorescence detection.
abstract: A rugged, simple, and selective method for the determination of danofloxacin and its primary metabolite, N-desmethyldanofloxacin, in cattle (liver, muscle, kidney, and fat) and chicken (liver and muscle) tissues was developed. The method is selective for danofloxacin and N-desmethyldanofloxacin over other veterinary important fluoroquinolones, such as enrofloxacin, ciprofloxacin, norfloxacin, and ofloxacin. Selectivity is achieved through a combination of extraction, chromatography, and fluorescence detection. The analytes were extracted from homogenized tissues using a methanol-perchloric-phosphoric acid solution. After centrifugation, direct injection of extraction supernate was possible. The limit of quantitation was 20 pg on column. Separation was achieved on an Inertsil C8 (5 microns, 100 A) column with dimensions of 250 x 4.6 mm I.D. The mobile phase consisted of 0.05 M phosphate buffer (pH 3.5)-acetonitrile (88:12). A fluorescence detector was utilized with an excitation wavelength of 280 nm and an emission wavelength of 440 nm. The assay was accurate and reproducible within the range of 10 to 500 ng/g for both danofloxacin and N-desmethyldanofloxacin. Intra-assay accuracy was between 98 and 101%, and precision was less than 4%. Inter-assay accuracy was between 99 and 102%, while precision was less than 2%. Recoveries for both analytes over the dynamic range were greater than 90% for all the tissues.
authors.affiliation: Department of Drug Metabolism, Pfizer Central Research Division, Groton, CT 06340, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Strelevitz
authors.forename: M C
authors.initials: MC
authors.lastname: Linhares
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D000890:Anti-Infective Agents / Q000378:metabolism*; D002417:Cattle; D002645:Chickens; D024841:Fluoroquinolones; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008460:Meat / Q000032:analysis*; D009132:Muscles / Q000378:metabolism; D015363:Quinolones / Q000032:analysis* / Q000378:metabolism*; D015203:Reproducibility of Results; D013050:Spectrometry, Fluorescence
chemical_list: D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D015363:Quinolones; C099500:N-desmethyldanofloxacin; C068581:danofloxacin