Immunoassay detection of drugs in racing horses. VII. Detection of acepromazine in equine urine and blood by ELISA and PCFIA.

We have developed and evaluated a one step enzyme-linked immunosorbent assay (ELISA) test and a particle concentration fluorescence immunoassay (PCFIA) test for acepromazine as part of a panel of pre- and post-race tests for illegal medications in racing horses. These tests are rapid, sensitive and economical and development of the tests occurred in less than seven months. The ELISA test detects acepromazine with an I-50 of about 150 pg/ml. In vivo, it readily detects the presence of acepromazine or its metabolites in equine blood and urine from 8 to 72 hours or longer, respectively, after administration of sub-therapeutic doses. In vitro, the ELISA test cross-reacts with analogs of acepromazine, suggesting that it will also detect the use of other phenothiazine tranquilizers. The PCFIA test detects acepromazine with an I-50 of about 10 ng/ml. When applied to pre-race screening of serum samples as part of the pre-race testing program at a midwestern racetrack, the PCFIA test detected a number of cases of acepromazine abuse. Screening of stored post-race urine samples from associated horses by the ELISA test 'flagged' numerous samples for acepromazine, suggesting a pattern of acepromazine abuse. To date about twenty of these acepromazine flagged samples have been confirmed positive on mass spectrometry. As such the ELISA and PCFIA tests described in this communication are capable of substantially improving the quality of pre- and post-race testing programs for phenothiazine tranquilizers in racing horses.

Immunoassay detection of drugs in racing horses. IV. Detection of fentanyl and its congeners in equine blood and urine by a one step ELISA assay.

We have developed and evaluated a one step enzyme-linked immunosorbent assay (ELISA) test for fentanyl as part of a panel of pre- and post-race tests for narcotic analgesics in racing horses. This ELISA test detects fentanyl with an I-50 of about 100 pg/ml. The test is economical in that it can be read with an inexpensive spectrophotometer, or even by eye. The test is rapid, and ten samples, a normal pre-race complement, can be analyzed in about twenty minutes. The test readily detects the presence of fentanyl or its metabolites in equine blood and urine from two and twenty-four hours respectively after administration of sub-therapeutic doses. The two antibodies evaluated also cross-react with the methylated analogs of fentanyl, sufetanil and carfentanil and the test detected these drugs shortly after their administration to horses. When introduced into routine screening, this test, in combination with another immunoassay test previously described, yielded 10 sufentanil positives. As such this test is capable of both improving the quality and reducing the cost of pre-race and post-race testing for fentanyl and a number of its congeners in racing horses.