title: Time-dependent effects of Klebsiella pneumoniae endotoxin on the telithromycin pharmacokinetics in rats; restoration of the parameters in 96-hour KPLPS rats to the control levels.
abstract: OBJECTIVE
  It has been reported that telithromycin is primarily metabolized via hepatic CYP3A4 and 3A1/2 in humans and rats, respectively, and that the protein expression of hepatic CYP3A subfamily significantly decreased (59.1% decrease) in 24-h KPLPS rats (lipopolysaccharide derived from Klebsiella pneumoniae; the protein expression was measured 24h after KPLPS administration) compared with that in control rats, but restored to that in control rats in 96-h KPLPS rats.
  
  
  METHODS
  The pharmacokinetic parameters of telithromycin were compared after intravenous and oral administration at a dose of 50mg/kg to control, 24-h KPLPS, and 96-h KPLPS rats.
  
  
  RESULTS
  After both intravenous and oral administration of telithromycin to 24-h KPLPS rats, the AUC of telithromycin became significantly greater (68.2% and 88.7% increase for intravenous and oral administration, respectively) and this could have been due to the significantly slower CL(NR) (45.7% decrease). Because telithromycin is a low hepatic extraction ratio drug, the slower CL(NR) could have been due to the decreased protein expression of the hepatic CYP3A subfamily compared with that in control rats, and was supported by the significantly slower in vitro CL(int) in hepatic microsomes (13.1% decrease). However, in 96-h KPLPS rats, the pharmacokinetic parameters of telithromycin restored fully to those in control rats due to restoration of the protein expression of the hepatic CYP3A subfamily to that in control rats. The protein expression of the intestinal CYP3A subfamily was comparable among three groups of rats.
  
  
  CONCLUSIONS
  These findings indicate the existence of the time-dependent effects of KPLPS on the pharmacokinetics of telithromycin in rats.
authors.affiliation: College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul 151-742, South Korea.
authors.forename: Joo H
authors.initials: JH
authors.lastname: Lee
authors.forename: Yu K
authors.initials: YK
authors.lastname: Cho
authors.forename: Young S
authors.initials: YS
authors.lastname: Jung
authors.forename: Young C
authors.initials: YC
authors.lastname: Kim
authors.forename: Myung G
authors.initials: MG
authors.lastname: Lee
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics* / Q000494:pharmacology; D051544:Cytochrome P-450 CYP3A / Q000378:metabolism / Q000494:pharmacology; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism / Q000494:pharmacology; D007275:Injections, Intravenous; D007413:Intestinal Mucosa / Q000378:metabolism; D048628:Ketolides / Q000493:pharmacokinetics*; D008070:Lipopolysaccharides / Q000235:genetics / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism; D008862:Microsomes, Liver / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D048628:Ketolides; C043237:Klebsiella O3 lipopolysaccharide; D008070:Lipopolysaccharides; D003577:Cytochrome P-450 Enzyme System; C465260:Cyp3a2 protein, rat; D051544:Cytochrome P-450 CYP3A; C106791:telithromycin