title: Determination of firocoxib in equine plasma using high performance liquid chromatography.
abstract: A new method of analysis has been developed and validated for the determination of firocoxib, a new nonsteroidal anti-inflammatory drug (NSAID) approved for use in horses and dogs to control pain and inflammation associated with osteoarthritis. Following a liquid extraction using ethyl acetate:hexane (40:60), samples were separated by isocratic reversed-phase HPLC on a Sunfire C(18) column and quantified using UV detection at 290 nm. The mobile phase was a mixture of water with 0.025% trifluoroacetic acid and acetonitrile, with a flow-rate of 1.1 ml/min. The procedure produced a linear curve over the concentration range 5-1500 ng/ml with a lower limit of quantification of 5 ng/ml. Intra- and inter-assay variability was less than 7%. The average recovery was 98%. The method is suitable for the analysis of clinical samples from pharmacokinetic studies and can also be used for small volume sample sizes.
authors.affiliation: University of Tennessee, Department of Comparative Medicine, College of Veterinary Medicine, 2407 River Drive, Knoxville, TN 37996, USA. scox6@utk.edu
authors.forename: S
authors.initials: S
authors.lastname: Cox
authors.forename: J
authors.initials: J
authors.lastname: Yarbrough
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000097:blood; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004355:Drug Stability; D006736:Horses / Q000097:blood*; D016014:Linear Models; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013449:Sulfonamides / Q000032:analysis; D013450:Sulfones / Q000097:blood*; D000096926:Benzenesulfonamides
chemical_list: D015107:4-Butyrolactone; D000894:Anti-Inflammatory Agents, Non-Steroidal; D013449:Sulfonamides; D013450:Sulfones; C471996:deracoxib; D000096926:Benzenesulfonamides; C487384:firocoxib