title: Effect of drug concentration on adsorption of levofloxacin by polyacrylonitrile haemofilters.
abstract: We studied an in vitro model of continuous venovenous haemofiltration to determine levofloxacin adsorption by polyacrylonitrile (PAN) filters. Four doses of levofloxacin (5, 25, 50 and 100 mg) were used, resulting in circulating concentrations of levofloxacin at 120 min of 3.56+/-0.14, 15.84+/-2.08, 31.42+/-1.95 and 58.23+/-1.10 mg/L, respectively. Adsorption at 2 h was 0.65+/-0.17, 5.99+/-2.49, 12.30+/-2.34 and 30.13+/-1.32 mg, respectively (P<0.001). From 2h to 4h, increasing the blood pump rate and the ultrafiltration rate had no effect on adsorption. When the concentration was decreased from 3.55+/-0.13 mg/L at 4h to 2.16+/-0.11 mg/L at 5 h by addition of lactated Ringer's solution, adsorption decreased from 0.67+/-0.16 mg to 0.21+/-0.25 mg (P<0.05). These data show that adsorption of levofloxacin by PAN haemofilters is concentration dependent and reversible in vitro and suggest that adsorption by haemofilters is unlikely to affect levofloxacin pharmacokinetics significantly in vivo.
authors.affiliation: Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong. tianqi@cuhk.edu.hk
authors.forename: Qi
authors.initials: Q
authors.lastname: Tian
authors.forename: Charles D
authors.initials: CD
authors.lastname: Gomersall
authors.forename: April
authors.initials: A
authors.lastname: Wong
authors.forename: Patricia
authors.initials: P
authors.lastname: Leung
authors.forename: Gordon
authors.initials: G
authors.lastname: Choi
authors.forename: Gavin M
authors.initials: GM
authors.lastname: Joynt
authors.forename: Perpetua
authors.initials: P
authors.lastname: Tan
authors.forename: Jeff
authors.initials: J
authors.lastname: Lipman
mesh_terms: D000180:Acrylic Resins; D000327:Adsorption; D000900:Anti-Bacterial Agents / Q000097:blood / Q000493:pharmacokinetics*; D004305:Dose-Response Relationship, Drug; D006440:Hemofiltration / Q000295:instrumentation*; D006801:Humans; D064704:Levofloxacin; D008954:Models, Biological; D015242:Ofloxacin / Q000097:blood / Q000493:pharmacokinetics*; D051437:Renal Insufficiency / Q000628:therapy
chemical_list: D000180:Acrylic Resins; D000900:Anti-Bacterial Agents; C010504:polyacrylonitrile; D064704:Levofloxacin; D015242:Ofloxacin