title: Tear, cornea, and aqueous humor concentrations of ciprofloxacin and moxifloxacin after topical ocular application in ophthalmologically normal horses.
abstract: OBJECTIVE
  To determine ocular tissue drug concentrations after topical ocular administration of 0.3% ciprofloxacin and 0.5% moxifloxacin in ophthalmologically normal horses.
  
  
  METHODS
  24 ophthalmologically normal adult horses.
  
  
  METHODS
  0.3% ciprofloxacin and 0.5% moxifloxacin solutions (0.1 mL) were applied to the ventral conjunctival fornix of 1 eye in each horse as follows: group 1 (n = 8) at 0, 2, 4, and 6 hours; group 2 (8) at 0, 2, 4, 6, and 10 hours; and group 3 (8) at 0, 2, 4, 6, 10, and 14 hours. Tears, cornea, and aqueous humor (AH) were collected at 8, 14, and 18 hours for groups 1, 2, and 3, respectively. Drug concentrations were determined via high-performance liquid chromatography.
  
  
  RESULTS
  Median (25th to 75th percentile) concentrations of ciprofloxacin for groups 1, 2, and 3 in tears (μg/mL) were 53.7 (25.5 to 88.8), 48.5 (19.7 to 74.7), and 24.4 (15.4 to 67.1), respectively; in corneal tissue (μg/g) were 0.95 (0.60 to 1.02), 0.37 (0.32 to 0.47), and 0.48 (0.34 to 0.95), respectively; and in AH were lower than the limit of quantification in all groups. Concentrations of moxifloxacin for groups 1, 2, and 3 in tears (μg/mL) were 188.7 (44.5 to 669.2), 107.4 (41.7 to 296.5), and 178.1 (70.1 to 400.6), respectively; in corneal tissue (μg/g) were 1.84 (1.44 to 2.11), 0.78 (0.55 to 0.98), and 0.77 (0.65 to 0.97), respectively; and in AH (μg/mL) were 0.06 (0.04 to 0.08), 0.03 (0.02 to 0.05), and 0.02 (0.01 to 0.04), respectively. Corneal moxifloxacin concentrations were significantly higher in group 1 than groups 2 and 3.
  
  
  CONCLUSIONS
  After topical ocular administration, fluoroquinolones can reach therapeutic concentrations in tears and corneal tissue of horses, even when there is an intact epithelium.
authors.affiliation: Veterinary Teaching Hospital, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA.
authors.forename: Hans D
authors.initials: HD
authors.lastname: Westermeyer
authors.forename: Diane V H
authors.initials: DV
authors.lastname: Hendrix
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Ward
authors.forename: Sherry K
authors.initials: SK
authors.lastname: Cox
mesh_terms: D000287:Administration, Topical; D000818:Animals; D000900:Anti-Bacterial Agents / Q000378:metabolism; D001082:Aqueous Humor / Q000378:metabolism*; D001372:Aza Compounds / Q000097:blood / Q000493:pharmacokinetics*; D002939:Ciprofloxacin / Q000097:blood / Q000493:pharmacokinetics*; D003315:Cornea / Q000378:metabolism*; D024841:Fluoroquinolones; D006734:Horse Diseases / Q000188:drug therapy; D006736:Horses / Q000097:blood / Q000378:metabolism*; D007634:Keratitis / Q000188:drug therapy / Q000662:veterinary; D000077266:Moxifloxacin; D011804:Quinolines / Q000097:blood / Q000493:pharmacokinetics*; D013666:Tears / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D001372:Aza Compounds; D024841:Fluoroquinolones; D011804:Quinolines; D002939:Ciprofloxacin; D000077266:Moxifloxacin