title: Quantitative HPLC-UV method for the determination of firocoxib from horse and dog plasma.
abstract: A sensitive reversed-phase HPLC-UV method was developed for the determination of firocoxib, a novel and highly selective COX-2 inhibitor, in plasma. A 1.0 mL dog or horse plasma sample is mixed with water and passed through a hydrophobic-lipophilic copolymer solid-phase extraction column to isolate firocoxib. Quantitation is based on an external standard curve. The method has a validated limit of quantitation of 25 ng/mL and a limit of detection of 10 ng/mL. The validated upper limit of quantitation was 2500 ng/mL for horses and 10,000 ng/mL for dogs. The average recoveries ranged from 88-93% for horse plasma and 96-103% for dog plasma. The coefficient of variation in all cases was less than 10%. This method is suitable for the analysis of clinical samples from pharmacokinetic and bioequivalence studies and drug monitoring.
authors.affiliation: Merial Limited, Pharmacokinetics and Drug Metabolism, 631 Route 1, North Brunswick, NJ 08902, USA. valerie.kvaternick@merial.com
authors.forename: Valerie
authors.initials: V
authors.lastname: Kvaternick
authors.forename: Thomas
authors.initials: T
authors.lastname: Malinski
authors.forename: Jill
authors.initials: J
authors.lastname: Wortmann
authors.forename: James
authors.initials: J
authors.lastname: Fischer
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000097:blood* / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004285:Dogs; D006736:Horses; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D013450:Sulfones / Q000097:blood* / Q000493:pharmacokinetics; D013810:Therapeutic Equivalency
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D013450:Sulfones; D015107:4-Butyrolactone; C487384:firocoxib