Pharmacokinetic variables and tissue residues of enrofloxacin and ciprofloxacin in healthy pigs.
OBJECTIVE
To determine pharmacokinetics of enrofloxacin and its metabolite ciprofloxacin after a single i.v. and i.m. administration of enrofloxacin and tissue residues after serial daily i.m. administration of enrofloxacin in pigs.


METHODS
20 healthy male pigs.


METHODS
8 pigs were used in a crossover design to investigate pharmacokinetics of enrofloxacin after a single i.v. and i.m. administration (2.5 mg/kg of body weight). Twelve pigs were used to study tissue residues; they were given daily doses of enrofloxacin (2.5 mg/kg, i.m. for 3 days). Plasma and tissue concentrations of enrofloxacin and ciprofloxacin were determined. Residues of enrofloxacin and ciprofloxacin were measured in fat, kidney, liver, and muscle.


RESULTS
Mean (+/-SD) elimination half-life and mean residence time of enrofloxacin in plasma were 9.64+/-1.49 and 12.77+/-2.15 hours, respectively, after i.v. administration and 12.06+/-0.68 and 17.15+/-1.04 hours, respectively, after i.m. administration. Half-life at alpha phase of enrofloxacin was 0.23+/-0.05 and 1.94+/-0.70 hours for i.v. and i.m. administration, respectively. Maximal plasma concentration was 1.17 +/-0.23 microg/ml, and interval from injection until maximum concentration was 1.81+/-0.23 hours. Renal and hepatic concentrations of enrofloxacin (0.012 to 0.017 microg/g) persisted for 10 days; however, at that time, ciprofloxacin residues were not detected in other tissues.


CONCLUSIONS
Enrofloxacin administered i.m. at a dosage of 2.5 mg/kg for 3 successive days, with a withdrawal time of 10 days, resulted in a sum of concentrations of enrofloxacin and ciprofloxacin that were less than the European Union maximal residue limit of 30 ng/g in edible tissues.
Anadón
A
A
Institute of Pharmacology and Toxicology, Consejo Superior de Investigaciones Científicas, Department of Toxicology, Faculty of Veterinary Medicine, Universidad Complutense de Madrid, Spain.
Martínez-Larrañaga
M R
MR
Díaz
M J
MJ
Fernández-Cruz
M L
ML
Martínez
M A
MA
Frejo
M T
MT
Martínez
M
M
Iturbe
J
J
Tafur
M
M
D000818:Animals; D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D019540:Area Under Curve; D002851:Chromatography, High Pressure Liquid; D002939:Ciprofloxacin / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D018592:Cross-Over Studies; D004350:Drug Residues / Q000493:pharmacokinetics*; D000077422:Enrofloxacin; D024841:Fluoroquinolones; D007273:Injections, Intramuscular; D007275:Injections, Intravenous; D008297:Male; D008657:Metabolic Clearance Rate; D008954:Models, Biological; D015363:Quinolones / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D013552:Swine
D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D015363:Quinolones; D000077422:Enrofloxacin; D002939:Ciprofloxacin