title: Disposition and tolerance of suxibuzone in horses.
abstract: Suxibuzone (SBZ), a nonsteroidal anti-inflammatory drug, was administered to 6 horses at a dose rate of 7.5 mg/kg bwt by intravenous (i.v.) route. Plasma and synovial fluid concentrations of suxibuzone and its main active metabolites, phenylbutazone (PBZ) and oxyphenbutazone (OPBZ), were measured simultaneously by a sensitive and specific high-performance liquid chromatographic method. The pharmacokinetic parameters were determined by noncompartmental analysis. Plasma SBZ concentrations rapidly decreased and were not detectable beyond 20 min after treatment. The parent drug was not detected in any synovial fluid samples. Average maximum plasma concentrations of PBZ (16.43 microg/ml) and OPBZ (2.37 microg/ml) were attained at 0.76 and 7.17 h, respectively. The mean residence time (MRT) of PBZ was 6.96 h in plasma. Oxyphenbutazone plasma concentrations were below those reached by phenylbutazone during the first 12 h after suxibuzone administration, even though its values were detectable for at least 24 h (MRT = 10.65 h). Plasma concentrations of PBZ and OPBZ exceeding EC50 and IC50 of TXB2 and PGE2 were reached by at least 12 h. Synovial fluid concentrations of PBZ and OPBZ were 2.87+/-0.37 microg/ml and 0.97+/-0.08 microg/ml at 9 h after suxibuzone administration and exceeded IC50 of PGE2 for at least this time. In the present study, suxibuzone was well tolerated following i.v. injection.
authors.affiliation: Cátedra de Farmacología, Facultad de Veterinaria, Universidad Complutense de Madrid, Spain.
authors.forename: M V
authors.initials: MV
authors.lastname: Jaraiz
authors.forename: C
authors.initials: C
authors.lastname: Rodriguez
authors.forename: M D
authors.initials: MD
authors.lastname: San Andres
authors.forename: F
authors.initials: F
authors.lastname: Gonzalez
authors.forename: M I
authors.initials: MI
authors.lastname: San Andres
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics*; D019540:Area Under Curve; D001772:Blood Cell Count / Q000662:veterinary; D002851:Chromatography, High Pressure Liquid / Q000662:veterinary; D006400:Hematocrit / Q000662:veterinary; D006736:Horses / Q000378:metabolism* / Q000502:physiology; D007213:Indomethacin / Q000097:blood / Q000493:pharmacokinetics; D007275:Injections, Intravenous / Q000662:veterinary; D008297:Male; D010113:Oxyphenbutazone / Q000097:blood / Q000493:pharmacokinetics; D010653:Phenylbutazone / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics; D013582:Synovial Fluid / Q000378:metabolism
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; C003371:suxibuzone; D010653:Phenylbutazone; D010113:Oxyphenbutazone; D007213:Indomethacin