Development of an ELISA using a universal method of enzyme-labelling drug-specific antibodies. Part I: Detection of dexamethasone in equine urine.
The development, validation, and application of an ELISA for dexamethasone in equine urine is described. The drug-protein conjugate was immobilised in microtitre plate wells and antiserum raised against the same drug-protein conjugate was allowed to compete with sample or standard drug and the immobilised drug-protein conjugate. The proportion of antiserum binding to the immobilised drug-protein conjugate was detected using a biotinylated protein G/extravidin-alkaline phosphatase complex in situ and measurement of the substrate product. The method was used to detect the presence of drug-derived material in unextracted diluted urine after the administration of a single i.m. dose of dexamethasone at approximately 0.04 mg/kg to a thoroughbred horse. Validation of the method was carried out against a radioimmunoassay and GC/MS analysis.
Roberts
C J
CJ
Horseracing Forensic Laboratory Limited, Newmarket, Suffolk, UK.
Jackson
L S
LS
D000818:Animals; D001710:Biotin; D003907:Dexamethasone / Q000652:urine*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006736:Horses; D008297:Male; D009419:Nerve Tissue Proteins; D012756:Sheep
C029152:G-substrate; D009419:Nerve Tissue Proteins; D001710:Biotin; D003907:Dexamethasone