title: The pharmacokinetics of thiamphenicol in lactating cows.
abstract: The pharmacokinetics of thiamphenicol were studied after intravenous and intramuscular administration of 25 mg/kg body weight in lactating cows. Distribution (t1/2 alpha) and elimination (t1/2 beta) half-lives of 6.10 +/- 1.39 min and 1.60 +/- 0.30 h, respectively, were obtained after intravenous administration. The body clearance was 3.9 +/- 0.077 ml/kg per min and the apparent volume of distribution was 1220.79 +/- 256.67 ml/kg. The rate at which thiamphenicol appeared in the milk, as indicated by the penetration half-life (t1/2P) (serum to quarters), was found to be 36.89 +/- 11.14 min. The equivalent elimination half-life (t1/2E) (quarters to serum) from the milk was 3.62 +/- 1.06 h and the peak thiamphenicol concentration in the milk was 23.09 +/- 3.42 micrograms/ml at 2.5 +/- 0.32 h. After intramuscular injection, the elimination half-life was 2.2 +/- 0.40 h, the absorption half-life was 4.02 +/- 1.72 min and the peak concentration in the serum was 30.90 +/- 5.24 micrograms/ml at 23 +/- 8.4 min. The bioavailability after intramuscular administration approached 100%. The penetration half-life was 50.59 +/- 6.87 min, the elimination half-life was 5.91 +/- 4.97 h and the mean peak concentration in the milk was 17.37 +/- 2.20 micrograms/ml at 3.4 +/- 0.22 h.
authors.affiliation: Cátedra de Farmacología, Farmacotecnia y Terapéutica, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, Argentina.
authors.forename: N
authors.initials: N
authors.lastname: Mestorino
authors.forename: M F
authors.initials: MF
authors.lastname: Landoni
authors.forename: M
authors.initials: M
authors.lastname: Alt
authors.forename: J O
authors.initials: JO
authors.lastname: Errecalde
mesh_terms: D000818:Animals; D001682:Biological Availability; D002417:Cattle; D005260:Female; D006207:Half-Life; D007273:Injections, Intramuscular; D007275:Injections, Intravenous; D007774:Lactation / Q000378:metabolism*; D008657:Metabolic Clearance Rate; D008892:Milk / Q000378:metabolism*; D013839:Thiamphenicol / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D013839:Thiamphenicol