Enzyme linked immunosorbent assay for detecting benzodiazepines in urine.

A relatively simple ELISA technique was developed for the detection of a range of benzodiazepines (BZs) in urine. The assay employs a mouse anti-oxazepam antibody that is highly specific for the BZs. The limit of detection using 10 microliters samples of urine was 0.3 microgram ml-1 oxazepam. N-Desmethyldiazepam showed equal cross-reactivity to oxazepam, 11 BZs cross-reacted weakly and flurazepam and chlordiazepoxide did not cross-react at levels reported to be found in urine. No cross-reactivity was observed with drugs of abuse and a range of therapeutic drugs commonly found in urine. The assay was used as a screen to detect the presence of BZs in urine from 88 addicts that had been screened by the EMIT technique and a radioreceptor assay (RRA) for BZs. The ELISA produced two false negatives that were EMIT and RRA positive whereas the EMIT produced four different false negatives that were positive by both ELISA and RRA. Thirty-three positives were common to all three assays. The ELISA was also used to monitor nitrazepam-like activity in the urine of a greyhound receiving 5 mg oral medication and the results were compared with those obtained by RRA. Both assays were able to detect nitrazepam-like activity for up to 10 h post-administration.

Direct determination of some phenothiazine sedatives in greyhound urine by fluoroimmunoassay.

Antibodies have been raised in rabbits to a chlorpromazine sulfoxide-bovine serum albumin immunogen and the resulting antiserum used to develop a magnetizable solid-phase antibody fluoroimmunoassay for the detection of sulfoxide metabolites of commonly used phenothiazine and thioxanthine neuroleptics. These assays were used to screen metabolite levels in the urine of a greyhound following oral medication with chlorpromazine in order to assess the potential of these assays as simple screens for detecting exposure of racing greyhounds to such sedatives. The urine samples were also screened for neuroleptic content using an established radioreceptor assay and by TLC. The immunoassay described represents a relatively simple, sensitive and group-specific alternative method for screening for medication with phenothiazine and structurally similar sedatives in urine samples.