A Validated Method for the Determination of Firocoxib in Equine Tissues

A new reversed-phase High Performance Liquid Chromatography (HPLC) method was developed and validated for the determination of firocoxib in equine tissue. Firocoxib was detected by ultraviolet detection at 290nm after undergoing a liquid extraction using ethyl acetate: hexane (40:60) and separation on a Sunfire C₁₈ column. The mobile phase consisted of water with 0.025% trifluoroacetic acid and acetonitrile (50:50), with a flow rate 1.1 mL/min. A concentration range of 5-1500ng/gm produced a linear curve with r²>0.99. The lower limit of quantification was 5ng/gm. The intra and inter assay variability was <10% and the average recovery was 97%.