title: Increased anterior chamber penetration of topical levofloxacin 0.5% after pulsed dosing in cataract patients.
abstract: OBJECTIVE
  This study aimed to investigate the rise in aqueous humour (AH) levels of levofloxacin after a specific perioperative pulsed topical drop regimen.
  
  
  METHODS
  Thirty patients undergoing phacoemulsification surgery were administered two preoperative drops of levofloxacin 0.5%, 30 mins apart, and three pulsed drops postoperatively, 5 mins apart. Aqueous humour levels of levofloxacin were measured at the start of surgery and from 5 mins to 90 mins after the last postoperative drop. Samples from individual patients were collected at the time of surgery and at one additional sampling interval by aqueous tap, and analysed using a high-performance liquid chromatography assay.
  
  
  RESULTS
  Aqueous humour levels of levofloxacin continued to rise gradually, reaching a mean peak level (C(max)) of 4.4 microg/ml (+/- 2.5) at 60 mins after the last postoperative drop was administered. This level exceeded the minimum inhibitory concentration of common ocular pathogens at least fourfold. At 90 mins after the last drop, mean AH levels remained > 3 microg/ml.
  
  
  CONCLUSIONS
  This is the first study to measure AH levels of levofloxacin after postoperative pulsed dosing in humans. Higher AH levels were found than in previously reported studies in which only preoperative drops were given and levels were measured at the time of surgery. Levels of levofloxacin continued to rise for 60 mins after administration of the last postoperative drop, demonstrating that delivery and maintenance of effective antibiotic levels may be achievable with alternative dosing schedules.
authors.affiliation: Department of Ophthalmology, Sahlgrenska University Hospital, Mölndal, Sweden. karin.sundelin@oft.gu.se
authors.forename: Karin
authors.initials: K
authors.lastname: Sundelin
authors.forename: David
authors.initials: D
authors.lastname: Seal
authors.forename: Susanne
authors.initials: S
authors.lastname: Gardner
authors.forename: Auli
authors.initials: A
authors.lastname: Ropo
authors.forename: Klaus
authors.initials: K
authors.lastname: Geldsetzer
authors.forename: Jukka
authors.initials: J
authors.lastname: Lokkila
authors.forename: Ulf
authors.initials: U
authors.lastname: Stenevi
mesh_terms: D000287:Administration, Topical; D000368:Aged; D000369:Aged, 80 and over; D000867:Anterior Chamber / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000493:pharmacokinetics; D002387:Cataract Extraction / Q000379:methods; D002851:Chromatography, High Pressure Liquid; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D064704:Levofloxacin; D008297:Male; D008875:Middle Aged; D015242:Ofloxacin / Q000008:administration & dosage / Q000493:pharmacokinetics*; D009994:Osmolar Concentration; D018918:Phacoemulsification; D011182:Postoperative Care; D011300:Preoperative Care; D020551:Pulse Therapy, Drug; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D064704:Levofloxacin; D015242:Ofloxacin