title: Prophylactic efficacy of ophthalmic quinolones in experimental endophthalmitis in rabbits.
abstract: OBJECTIVE
  The aim of this study was to determine the efficacy of 0.3% gatifloxacin ophthalmic solution in preventing bacterial endophthalmitis in rabbits.
  
  
  METHODS
  Eighty-four (84) albino phakic rabbits were injected unilaterally with 2 x 10(4) colony forming units of Enterococcus faecalis into the anterior chamber. The eyes received 0.3% ofloxacin ophthalmic ointment or 0.3% gatifloxacin ophthalmic solution with different regimens in three separate experiments: (1) 1 or 3 drops of gatifloxacin every 2 h or a single application of ofloxacin for 1 day; (2) 3 drops/day of gatifloxacin application started at 0, 6, and 24 h postinoculation, or 1 drop at 0 h, and 3 times daily gatifloxacin for the following 3 days; and (3) 1 or 3 drops of gatifloxacin application started at 0 h and no further application for the following 3 days. The control eyes received no treatment in the three experiments. The effectiveness of these different regimens was assessed by slit-lamp biomicroscopy and bacterial colony counts. The ocular penetration of the drugs was determined in a separate experiment, using 36 normal albino rabbits.
  
  
  RESULTS
  The concentration-time curves for gatifloxacin and ofloxacin appeared parallel, with mean peak concentrations of 1161 and 219 ng/mL, respectively, at 1 h postinstillation. In Experiment 1, gatifloxacin significantly reduced the inflammation and the number of living bacteria in the aqueous humor, compared with controls, whereas ofloxacin ointment did not. A single application of ofloxacin ointment was not better than 1 drop of gatifloxacin. The results of Experiment 2 showed that the effectiveness of gatifloxacin decreased as the interval between the inoculation and the onset of treatment increased. In Experiment 3, only 3 drops of gatifloxacin on day 1 kept the inflammation significantly lower than that in the control for 4 days.
  
  
  CONCLUSIONS
  Immediate postoperative prophylaxis would likely be effective in reducing the risk of enterococcal endophthalmitis by topical gatifloxacin.
authors.affiliation: Research Laboratory for Drug Development, Senju Pharmaceutical Co., Ltd., Kobe, Hyogo, Japan. tmwada@senju.co.jp
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Wada
authors.forename: Seiko
authors.initials: S
authors.lastname: Kozai
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Tajika
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Sakaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Suzuki
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ohashi
mesh_terms: D000818:Animals; D000867:Anterior Chamber / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000627:therapeutic use*; D001682:Biological Availability; D018450:Disease Progression; D009877:Endophthalmitis / Q000382:microbiology / Q000517:prevention & control*; D013293:Enterococcus faecalis; D005123:Eye / Q000378:metabolism; D024841:Fluoroquinolones / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use; D000077734:Gatifloxacin; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology / Q000517:prevention & control; D008297:Male; D015242:Ofloxacin / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use; D009824:Ointments; D009883:Ophthalmic Solutions; D015363:Quinolones / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000627:therapeutic use*; D011817:Rabbits
chemical_list: D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D009824:Ointments; D009883:Ophthalmic Solutions; D015363:Quinolones; D015242:Ofloxacin; D000077734:Gatifloxacin