title: High performance liquid chromatography and pharmacokinetics of the non-steroidal anti-inflammatory drug oxindanac in calves.
abstract: A high-performance liquid chromatographic method for the determination of the non-steroidal anti-inflammatory drug, oxindanac, in calf plasma is described. Recoveries over the concentration range 0.375 to 62.5 micrograms/ml were 90.2-107.8% with interassay coefficients of variation of 2.1-22.3%. The limit of detection was estimated as 0.10 micrograms/ml and the limit of quantification calculated to be 0.24 micrograms/ml in a 1 ml plasma sample. This method was used to establish the pharmacokinetics following intravenous (i.v.), intramuscular (i.m.) and oral (p.o.) administration to calves of oxindanac at a dose rate of 2 mg/kg. The elimination t1/2 was long (t1/2 21.2 h after i.v. injection) and absorption was rapid (t1/2a 0.072 h) and complete (F > 100%) following i.m. administration. Bioavailability was incomplete (F = 66.6%) following p.o. administration to calves that had been fed on milk, and Wagner-Nelson analysis revealed two absorption phases (t1/2's 0.20 and 1.9 h). Oxindanac produced long-lasting inhibition of serum TxB2 production, with mean Emax values (% inhibition) of 96.8, 94.1 and 81.3 following i.v., i.m. and p.o. administration, respectively. A single i.v. or i.m. injection of 2 mg/kg oxindanac will probably be active in calves for at least 36-48 h.
authors.affiliation: CIBA-GEIGY Animal Health, Centre de Recherches Agricoles, St. Aubin, Switzerland.
authors.forename: J N
authors.initials: JN
authors.lastname: King
authors.forename: C
authors.initials: C
authors.lastname: Mauron
authors.forename: M J
authors.initials: MJ
authors.lastname: Voirol
authors.forename: C
authors.initials: C
authors.lastname: Le Goff
authors.forename: S A
authors.initials: SA
authors.lastname: Hauffe
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000493:pharmacokinetics*; D001682:Biological Availability; D002417:Cattle / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary*; D004333:Drug Administration Routes; D006207:Half-Life; D007192:Indenes / Q000008:administration & dosage / Q000493:pharmacokinetics*; D007273:Injections, Intramuscular / Q000662:veterinary; D007275:Injections, Intravenous / Q000662:veterinary; D008297:Male; D015203:Reproducibility of Results; D013929:Thromboxane B2 / Q000097:blood
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D007192:Indenes; D013929:Thromboxane B2; C039724:oxindanac