CEDIA dau Benzodiazepine Screening Assay: A Reformulation*

Robert C. Meatherall, Albert D. Fraser
1998 Journal of Analytical Toxicology  
The CEDIA dau Benzodiazepine assay has been reformulated to include online hydrolysis of urinary benzodiazepine glucuronide conjugates. The new antibody possesses enhanced cross-reactivities toward the low-close benzodiazepines, which are excreted at low urinary drug-metabolite concentrations. The screening method was evaluated using Iorazepam as the probe benzodiazepine. Four subjects each consumed a l-rag Iorazepam tablet. Sequential urine voids over the same time intervals were collected for
more » ... the next 48 h. Twelve postdose urine samples were collected from each subject. Positive results were obtained from 5-24 h to 2-35 h using a 200-ng/mt nitrazepam calibration cutoff. There was no practical difference between hydrolyzing online with the supplied E. coil ~-glucuronidase or offline with Helix pomatia 13-glucuronidase purchased separately. Without hydrolysis, all urine samples tested negative. The cross-reactivities of Iorazepam in terms of nitrazepam calibration equivalents, varied from 108 to 178% for Iorazepam concentrations between 50 and 2500 ng/mL. Lorazepam glucuronide gave cross-reactivities (expressed as Iorazepam base) between 72 and 136% using the online hydrolysis procedure with E. coli ~-glucuronidase. Offline hydrolysis with Helix pomatia gave cross-reactivities between 84 and 134%. Without hydrolysis, Iorazepam glucuronide gave less than 4% cross-reactivity in the assay.
doi:10.1093/jat/22.4.270 pmid:9681328 fatcat:vnnkbyai7rhmlhx6dhzojhwje4