title: Determination of ciprofloxacin levels in chinchilla middle ear effusion and plasma by high-performance liquid chromatography with fluorescence detection.
abstract: An isocratic high-performance liquid chromatographic method has been developed to determine ciprofloxacin levels in chinchilla plasma and middle ear fluid. Ciprofloxacin and the internal standard, difloxacin, were separated on a Keystone ODS column (100 x 2.1 mm I.D., 5 microns Hypersil) using a mobile phase of 30 mM phosphate buffer (pH 3), 20 mM triethylamine, 20 mM sodium dodecyl sulphate-acetonitrile (60:40, v/v). The retention times were 3.0 min for ciprofloxacin and 5.2 min for difloxacin. This fast, efficient protein precipitation procedure together with fluorescence detection allows a quantification limit of 25 ng/ml with a 50 microliters sample size. The detection limit is 5 ng/ml with a signal-to-noise ratio of 5:1. Recoveries (mean +/- S.D., n = 5) at 100 ng/ml in plasma and middle ear fluid were 89.4 +/- 1.2% and 91.4 +/- 1.6%, respectively. The method was evaluated with biological samples taken from chinchillas with middle ear infections after administering ciprofloxacin.
authors.affiliation: College of Pharmacy, Department of Pharmacy Practice, University of Minnesota, Minneapolis 55455.
authors.forename: M
authors.initials: M
authors.lastname: Lovdahl
authors.forename: J
authors.initials: J
authors.lastname: Steury
authors.forename: H
authors.initials: H
authors.lastname: Russlie
authors.forename: D M
authors.initials: DM
authors.lastname: Canafax
mesh_terms: D000818:Animals; D001826:Body Fluids / Q000378:metabolism; D002682:Chinchilla; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002939:Ciprofloxacin / Q000032:analysis* / Q000097:blood / Q000493:pharmacokinetics; D004432:Ear, Middle / Q000378:metabolism*; D015203:Reproducibility of Results; D013050:Spectrometry, Fluorescence
chemical_list: D002939:Ciprofloxacin