title: Comparative pharmacokinetics of an injectable cephalexin suspension in beef cattle.
abstract: This study describes and compares the pharmacokinetics of a single 7.5mg/kg dose of cephalexin monohydrate oil-based 20% suspension after its administrations to six cows by the intramuscular (i.m.) and subcutaneous (s.c.) routes, and to five calves by the i.m. route. Significantly (P<0.05) higher peak plasma concentrations (5.6+/-0.79microg/ml versus 3.93+/-1.24microg/ml) and lower half-life (1.81+/-0.56h versus 4.21+/-0.82h) and mean residence time (4.12+/-1.07h versus 6.63+/-0.85h) were obtained after i.m. administration when compared to the s.c. administration to cows. No differences were found between pharmacokinetic parameters calculated for cows and calves. Cephalexin plasma concentrations remained above 0.5-0.75microg/ml for 11-14h and 8-9h after the s.c. and i.m. administrations, respectively. Thus, route of administration may be an important issue to be considered when calculating dosage schedules for successful treatments and safe withdrawal times for veterinary medicines.
authors.affiliation: Department of Pharmacology, University of Buenos Aires, Chorroarín 280, 1427 Buenos Aires, Argentina.
authors.forename: S
authors.initials: S
authors.lastname: Waxman Dova
authors.forename: G
authors.initials: G
authors.lastname: Albarellos
authors.forename: V
authors.initials: V
authors.lastname: Kreil
authors.forename: L
authors.initials: L
authors.lastname: Montoya
authors.forename: L
authors.initials: L
authors.lastname: Ambros
authors.forename: R
authors.initials: R
authors.lastname: Hallu
authors.forename: M
authors.initials: M
authors.lastname: Rebuelto
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics; D019540:Area Under Curve; D002417:Cattle; D002506:Cephalexin / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D005260:Female; D006207:Half-Life; D007267:Injections; D008460:Meat
chemical_list: D000900:Anti-Bacterial Agents; D002506:Cephalexin