DISPOSITION OF HUMAN DRUG PREPARATIONS IN THE HORSE - VI - TIAPROFENIC ACID

Urinary and plasma concentrations of the nonsteroidal anti-inflammator y drug tiaprofenic acid were determined following oral and intramuscul ar administration of a dose of 1 g to five fasted horses. Quantitation was performed by high-performance Liquid chromatography (HPLC). The l imit of quantitation (LOQ) was 0.1 mu g/ml and 0.5 mu g/ml in 2 ml pla sma and 1 ml urine, respectively. Assay precision and extraction recov ery were between acceptable values. Tiaprofenic acid pharmacokinetics were described by non-compartment analysis of the data. Absorption was faster after oral administration as maximum plasma concentrations (or al: 6.0+/-3.3 mu g/ml; intramuscular: 6.6+/-2.5 mu g/ml) were obtained after 1 h (oral) compared to 1.6+/-0.4 h (intramuscular) post dosage. Plasma binding (66+/-3%) was lower than measured in other species. Ti aprofenic acid was detected in urine for at least 24 h. The percentage of the parent drug excreted in the first 12 h after oral and intramus cular administration was 38+/-6% and 34+/-5%, respectively. (C) 1997 E lsevier Science B.V.