Development of IC-ELISA and immunochromatographic strip assay for the detection of flunixin meglumine in milk

Flunixin meglumine (FM) is a novel nonsteroidal anti-inflammatory drug for animals, which has antipyretic, analgesic, and anti-inflammatory effects. The drug, which was originally used to relieve inflammation in horses, musculoskeletal disorders, and pain, has been approved for use in endotoxemia, infectious diseases in swine, etc. A sensitive anti-FM monoclonal antibody 2H4 was prepared and used to develop an indirect competitive enzyme-linked immunosorbent assay and immunochromatographic strip assay for the detection of FM in milk. The complete antigen and coating antigen were conjugated with bovine serum albumin and ovalbumin, respectively. The monoclonal antibody 2H4, with a half inhibition concentration of 0.29 ng/mL, had a limit of detection of 0.432 ng/mL and a linear range of detection of 0.08664–0.97226 ng/mL. A sensitive and convenient immunochromatographic strip assay was developed with an FM cutoff value of 0.29 ng/mL. The developed methods were suitable for the detection of FM in milk.