Pharmacokinetics of a combination preparation of ampicillin and sulbactam in turkeys.
OBJECTIVE
To investigate the disposition kinetics of ampicillin and sulbactam after IV and IM administration of an ampicillin-sulbactam (2:1) preparation and determine the bioavailability of the combined preparation after IM administration in turkeys.


METHODS
10 healthy large white turkeys.


METHODS
In a crossover study, turkeys were administered the combined preparation IV (20 mg/kg) and IM (30 mg/kg). Blood samples were collected before and at intervals after drug administrations. Plasma ampicillin and sulbactam concentrations were measured by use of high-performance liquid chromatography; plasma concentration-time curves were analyzed via compartmental pharmacokinetics and noncompartmental methods.


RESULTS
The drugs were distributed according to an open 2-compartment model after IV administration and a 1-compartment model (first-order absorption) after IM administration. For ampicillin and sulbactam, the apparent volumes of distribution were 0.75+/-0.11 L/kg and 0.74+/-0.10 L/kg, respectively, and the total body clearances were 0.67+/-0.07 L x kg(-1) x h(-1) and 0.56+/-0.06 L x kg(-1) x h(-), respectively. The elimination half-lives of ampicillin after IV and IM administration were 0.78+/-0.12 hours and 0.89+/-0.17 hours, respectively, whereas the corresponding half-lives of sulbactam were 0.91+/-0.12 hours and 0.99+/-0.16 hours, respectively. Bioavailability after IM injection was 58.87+/-765% for ampicillin and 53.75+/-5.35% for sulbactam.


CONCLUSIONS
Results indicated that a regimen of loading and maintenance doses of 300 mg of the ampicillin-sulbactam (2:1) combination/kg every 8 hours could be clinically useful in turkeys. This dosage regimen maintained plasma concentrations of ampicillin > 0.45 microg/mL in turkeys.
Fernández-Varón
Emilio
E
Department of Pharmacology, Faculty of Veterinary Medicine, University of Murcia, Campus de Espinardo, 30 071-Murcia, Spain.
Cárceles
Carlos M
CM
Espuny
Alberto
A
Marín
Pedro
P
Escudero
Elisa
E
D000667:Ampicillin / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000818:Animals; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D018592:Cross-Over Studies; D004359:Drug Therapy, Combination / Q000493:pharmacokinetics*; D005260:Female; D008297:Male; D013407:Sulbactam / Q000008:administration & dosage / Q000493:pharmacokinetics*; D014422:Turkeys / Q000378:metabolism*
D000667:Ampicillin; D013407:Sulbactam