Pharmacokinetics of tolfenamic acid in the horse.
The pharmacokinetics of tolfenamic acid were studied in five ponies after an intravenous (iv) administration (2 mg/kg bodyweight [bwt]) and in four horses after an oral administration (30 mg/kg bwt) of tolfenamic acid. The plasma levels were determined by high pressure liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS). For the iv administration, a three-compartment model was used to represent the plasma concentration-time curve of the drug. The elimination half-life of the compound was 6.1 +/- 1.5 h, the total body clearance was 72.4 +/- 16.7 ml/kg bwt/h and the steady-state volume of distribution 0.32 +/- 0.11 litres/kg bwt. For the oral administration, absorbtion was delayed with a mean lag-time to absorption of 32 +/- 28 mins. The peak plasma concentration 11.1 +/- 0.69 micrograms/ml was observed after a highly variable delay ranging from 1.9 to 6.5 h post administration. The terminal half-life (4.2 +/- 0.48 h) was very similar to that obtained after iv administration. Tolfenamic acid could not be detected in equine plasma with the described analytical methods more than 48 h after drug administration.
Jaussaud
P
P
INRA-ENVL Research Laboratory for Equine Sport, National School of Veterinary Medicine, Marcy I'Etoile, France.
Guieu
D
D
Bellon
C
C
Barbier
B
B
Lhopital
M C
MC
Sechet
R
R
Courtot
D
D
Toutain
P L
PL
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D001800:Blood Specimen Collection / Q000662:veterinary; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D005260:Female; D006207:Half-Life; D006736:Horses / Q000378:metabolism*; D007275:Injections, Intravenous; D008297:Male; D015203:Reproducibility of Results; D062367:ortho-Aminobenzoates / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*
D000894:Anti-Inflammatory Agents, Non-Steroidal; D062367:ortho-Aminobenzoates; C009500:tolfenamic acid