Pharmacokinetics of diclofenac in sheep following intravenous and intramuscular administration.
OBJECTIVE
The aim of this work was to examine the pharmacokinetics of diclofenac (DCLF) in sheep after intravenous (IV) and intramuscular (IM) dosing.


METHODS
Healthy male Najdi sheep.


METHODS
Diclofenac (1 mg kg(-1)) was administered to ten clinically healthy-male Najdi sheep IV or IM (n = 5 each). Blood samples (5 mL) were collected and serum was separated for drug analysis by high-performance liquid chromatography with UV detection. Diclofenac pharmacokinetic parameters were determined by noncompartmental analysis.


RESULTS
Diclofenac is quickly eliminated from sheep with a terminal T(1/2lambda) of 2-3 hours for both routes of administration. Total DCLF clearance after IV and IM administration was 87.86 +/- 24.10 and 85.69 +/- 40.76 mL kg(-1) hour(-1) respectively. The absolute bioavailability of IM DCLF appears to be approximately 100%.


CONCLUSIONS
The drug should be administered two to three times daily in sheep by IM or IV injection to maintain therapeutic concentrations. Additional studies are needed to evaluate the route of elimination of DCLF in sheep including metabolites formation and the significance of enterohepatic circulation.
Altaher
Abdulla Y
AY
Department of Pharmacology, College of Veterinary Medicine and Animal Resources, King Faisal University, Houfof, Saudi Arabia. alkharfy@ksu.edu.sa
Alkharfy
Khalid M
KM
Al-Hadiya
Badraddin M
BM
Khan
Rao Muzaffar A
RM
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D019540:Area Under Curve; D004008:Diclofenac / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D007273:Injections, Intramuscular / Q000662:veterinary; D007275:Injections, Intravenous / Q000662:veterinary; D008297:Male; D012756:Sheep / Q000378:metabolism*
D000894:Anti-Inflammatory Agents, Non-Steroidal; D004008:Diclofenac