Pharmacokinetics of florfenicol following intravenous and intramuscular doses to cattle.
The disposition of florfenicol after single intravenous and intramuscular doses of 20 mg of florfenicol/kg of body weight (b.w.) to feeder calves was investigated. Serum florfenicol concentrations were determined by a sensitive high performance liquid chromatographic method with a limit of quantitation of 0.025 microgram/ml. The extent of serum protein binding of florfenicol was only 13.2% at a serum florfenicol concentration of 3.0 micrograms/ml. Serum concentration-time data after intravenous administration were best described by a triexponential equation. Total body clearance and steady state volume of distribution were 3.75 ml/min/kg b.w. and 761 ml/kg b.w., respectively. The terminal half-life after intravenous administration was 159 min. The absolute systemic availability after intramuscular administration was 78.5% (range: 59.3-106%) and the harmonic mean of the terminal half-life was 1098 minutes, indicating slow release of the florfenicol from the formulation at the intramuscular injection site.
Schering-Plough Corporation, Cranford, New Jersey.
R D
RD
Lobell
K J
KJ
Varma
J C
JC
Johnson
R A
RA
Sams
D F
DF
Gerken
S M
SM
Ashcraft
D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D001682:Biological Availability; D001798:Blood Proteins / Q000378:metabolism; D002417:Cattle / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006207:Half-Life; D007273:Injections, Intramuscular / Q000662:veterinary; D007275:Injections, Intravenous / Q000662:veterinary; D008297:Male; D013839:Thiamphenicol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics
D000900:Anti-Bacterial Agents; D001798:Blood Proteins; C035534:florfenicol; D013839:Thiamphenicol