Determination of firocoxib in equine plasma using high performance liquid chromatography

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Vol. 879; no. 2; pp. 205 - 208
• Main Authors: Cox, S., Yarbrough, J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.01.2011; Elsevier
• Subjects: 4-Butyrolactone - analogs & derivatives; 4-Butyrolactone - blood; Acetonitrile; Analgesic; Analysis; Analytical, structural and metabolic biochemistry; Animals; Anti-Inflammatory Agents, Non-Steroidal - blood; Biocompatibility; Biological and medical sciences; Biomedical materials; blood plasma; Chromatography; Chromatography, High Pressure Liquid - methods; Dogs; Drug Stability; Extraction; Firocoxib; Fundamental and applied biological sciences. Psychology; General pharmacology; Horses; Horses - blood; HPLC; Linear Models; Liquids; Medical sciences; new methods; nonsteroidal anti-inflammatory agents; NSAID; Pain; Pharmacokinetics; Pharmacology. Drug treatments; Reproducibility of Results; reversed-phase high performance liquid chromatography; Sensitivity and Specificity; Sulfonamides - analysis; Sulfones - blood; Analgesic; Firocoxib; Pharmacokinetics; NSAID; HPLC; Prostaglandin-endoperoxide synthase; Biological fluid; Enzyme; Enzyme inhibitor; HPLC chromatography; Cyclooxygenase 2 inhibitor; Determination; Blood plasma; Non steroidal antiinflammatory agent; Vertebrata; Mammalia; Horse; Oxidoreductases; Perissodactyla; Ungulata; Quantitative analysis
• ISSN: 1570-0232; 1873-376X
• DOI: 10.1016/j.jchromb.2010.11.026

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 C18 column and quantified using UV detection at 290nm. The mobile phase was a mixture of water with 0.025% trifluoroacetic acid and acetonitrile, with a flow-rate of 1.1ml/min. The procedure produced a linear curve over the concentration range 5–1500ng/ml with a lower limit of quantification of 5ng/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.