The excretion of ibuprofen by the horse - a preliminary report.

The anti-inflammatory drug Ibuprofen [(+/-)-2-(p-isobutylphenyl) propionic acid] was estimated in the blood and urine of a horse using gas-liquid chromatography of the silylated derivative. Levels of the drug in the two body fluids were measured over a period of about 24 hours after administering a 12 gm dose of Ibuprofen. Plasma peak levels were observed within 30 to 60 min, and the drug was no longer detectable in the plasma by 8 hr. Urinary peak levels were observed 200 to 300 min after dosing, and the drug was no longer detectable in the urine by about 28 hr. It was observed that only 2% to 6% of the free unchanged drug was excreted in the urine.