title: Ocular penetration of intravenously administered enrofloxacin in the horse.
abstract: BACKGROUND
  Information on antibiotic concentrations in the equine eye following systemic therapy is limited. Reports that Leptospira spp. are frequently present in the eyes of horses with recurrent uveitis, emphasises a need for studies on ocular concentrations of specific antibiotics.
  
  
  OBJECTIVE
  1) Enrofloxacin, administered i.v. at 7.5 mg/kg bwt q. 24 h, results in aqueous humour concentrations greater than the reported minimum inhibitory concentration (MIC) for Leptospira pomona. 2) Aqueous humour paracentesis sufficiently disrupts the blood-aqueous humour barrier (BAB) to cause an increase in aqueous humour protein and enrofloxacin concentrations.
  
  
  METHODS
  Aqueous humour enrofloxacin and total protein concentrations were determined in 6 healthy, mature horses after i.v. administration of enrofloxacin. Paracentesis was performed on the left eye on Days 3 and 4, 1 h following enrofloxacin administration, to determine enrofloxacin concentrations in healthy eyes and in eyes with mechanical disruption of the BAB. Paracentesis was also performed on the right eye 23 h after enrofloxacin administration. Blood samples were collected from the horses at identical times to determine enrofloxacin aqueous humour:plasma ratios.
  
  
  RESULTS
  Mean +/- s.d. enrofloxacin concentration in the aqueous humour 1 h post administration on Day 3 was 0.32 +/- 0.10 mg/l (range 0.18-0.47); and aqueous humour enrofloxacin, total protein and aqueous humour:plasma enrofloxacin ratios were higher on Day 4 than Day 3.
  
  
  CONCLUSIONS
  Following disruption of the BAB, enrofloxacin concentrations were above the reported MIC for Leptospira pomona.
authors: Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA.
authors: T J
authors: TJ
authors: Divers
authors: N L
authors: NL
authors: Irby
authors: H O
authors: HO
authors: Mohammed
authors: W S
authors: WS
authors: Schwark
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics*; D001082:Aqueous Humor / Q000737:chemistry; D019540:Area Under Curve; D018916:Blood-Aqueous Barrier; D000077422:Enrofloxacin; D024841:Fluoroquinolones / Q000493:pharmacokinetics*; D006734:Horse Diseases / Q000188:drug therapy*; D006736:Horses; D007275:Injections, Intravenous / Q000662:veterinary; D007919:Leptospira / Q000187:drug effects; D007922:Leptospirosis / Q000188:drug therapy / Q000662:veterinary*; D019152:Paracentesis / Q000662:veterinary; D016896:Treatment Outcome; D014605:Uveitis / Q000188:drug therapy / Q000662:veterinary*
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D000077422:Enrofloxacin