title: Enantiospecific ketoprofen concentrations in plasma after oral and intramuscular administration in growing pigs.
abstract: BACKGROUND
  Ketoprofen is a non-steroidal anti-inflammatory drug which has been widely used for domestic animals. Orally administered racemic ketoprofen has been reported to be absorbed well in pigs, and bioavailability was almost complete. The objectives of this study were to analyze R- and S-ketoprofen concentrations in plasma after oral (PO) and intra muscular (IM) routes of administration, and to assess the relative bioavailability of racemic ketoprofen for both enantiomers between those routes of administration in growing pigs.
  
  
  METHODS
  Eleven pigs received racemic ketoprofen at dose rates of 4 mg/kg PO and 3 mg/kg IM in a randomized, crossover design with a 6-day washout period. Enantiomers were separated on a chiral column and their concentrations were determined by liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were calculated and relative bioavailability (Frel) was determined for S and R -ketoprofen.
  
  
  RESULTS
  S-ketoprofen was the predominant enantiomer in pig plasma after administration of the racemic mixture via both routes. The mean (± SD) maximum S-ketoprofen concentration in plasma (7.42 mg/L ± 2.35 in PO and 7.32 mg/L ± 0.75 in IM) was more than twice as high as that of R-ketoprofen (2.55 mg/L ± 0.99 in PO and 3.23 mg/L ± 0.70 in IM), and the terminal half-life was three times longer for S-ketoprofen (3.40 h ± 0.91 in PO and 2.89 h ± 0.85 in IM) than R-ketoprofen (1.1 h ± 0.90 in PO and 0.75 h ± 0.48 in IM). The mean (± SD) relative bioavailability (PO compared to IM) was 83 ± 20% and 63 ± 23% for S-ketoprofen and R-ketoprofen, respectively.
  
  
  CONCLUSIONS
  Although some minor differences were detected in the ketoprofen enantiomer concentrations in plasma after PO and IM administration, they are probably not relevant in clinical use. Thus, the pharmacological effects of racemic ketoprofen should be comparable after intramuscular and oral routes of administration in growing pigs.
authors.affiliation: Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland. katja.m.mustonen@helsinki.fi
authors.forename: Katja
authors.initials: K
authors.lastname: Mustonen
authors.forename: Anneli
authors.initials: A
authors.lastname: Niemi
authors.forename: Marja
authors.initials: M
authors.lastname: Raekallio
authors.forename: Mari
authors.initials: M
authors.lastname: Heinonen
authors.forename: Olli At
authors.initials: OA
authors.lastname: Peltoniemi
authors.forename: Mari
authors.initials: M
authors.lastname: Palviainen
authors.forename: Mia
authors.initials: M
authors.lastname: Siven
authors.forename: Marikki
authors.initials: M
authors.lastname: Peltoniemi
authors.forename: Outi
authors.initials: O
authors.lastname: Vainio
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000097:blood / Q000493:pharmacokinetics*; D019540:Area Under Curve; D001682:Biological Availability; D002853:Chromatography, Liquid / Q000662:veterinary; D018592:Cross-Over Studies; D005260:Female; D006207:Half-Life; D007273:Injections, Intramuscular / Q000662:veterinary; D007660:Ketoprofen / Q000097:blood / Q000493:pharmacokinetics*; D008297:Male; D013237:Stereoisomerism; D013552:Swine / Q000378:metabolism*; D053719:Tandem Mass Spectrometry / Q000662:veterinary
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D007660:Ketoprofen