Pharmacokinetics and bioavailability of cefazolin in horses.
The pharmacokinetics and bioavailability of cefazolin given (IV, IM) to horses at the dosage of 11 mg/kg were investigated. The disposition of cefazolin given by IV route was characterized by a rapid disposition phase with a half-life of 5 to 10 minutes and a subsequent slower elimination phase with a half-life of 35 to 46 minutes. The total plasma clearance of cefazolin averaged 5.51 ml/min/kg and was due mainly to renal clearance (5.39 ml/min/kg) of unchanged drug. The volume of distribution at steady-state averaged 188 ml/kg. Plasma protein binding of cefazolin at a concentration of 10 micrograms/ml averaged 8.1 +/- 1.9%. Given by the IM route, cefazolin was rapidly absorbed; the extent of bioavailability was 78.4 +/- 18.8%, and the terminal half-life ranged from 49 to 99 minutes. Thus, cefazolin was extensively absorbed, but was eliminated more slowly than after IV administration.
D000818:Animals; D001682:Biological Availability; D002437:Cefazolin / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006207:Half-Life; D006736:Horses / Q000378:metabolism*; D007273:Injections, Intramuscular / Q000662:veterinary; D007275:Injections, Intravenous / Q000662:veterinary; D011485:Protein Binding
D002437:Cefazolin