title: Fentanyl receptor assay. II. Utilization of a radioreceptor assay for the analysis of fentanyl analogs in urine.
abstract: A radioreceptor assay has been developed to measure fentanyl and fentanyl-like drugs in biological specimens. The assay is based on the competition of these drugs with [3H]fentanyl for opioid receptors. Rats were injected intravenously with fentanyl (15 micrograms/kg), alpha-methylfentanyl (15 micrograms/kg), (+/-)-cis-3-methylfentanyl (15 micrograms/kg), butyrylfentanyl (0.48 mg/kg), and benzylfentanyl (3.19 mg/kg). Urine samples were analyzed by radioreceptor assay (RRA), radioimmunoassay (RIA), and gas chromatography/mass spectrometry (GC/MS). The time-course of urinary analysis of fentanyl analogs showed some discrepancies. RRA measurement of urine concentrations of (+/-)-cis-3-methylfentanyl that were undetectable by RIA gave results 5-10 times higher than values obtained by GC/MS. Concentrations of alpha-methylfentanyl obtained by RRA and GC/MS were similar; however, these samples were negative by RIA. Following the administration of benzylfentanyl, urinary concentrations were not detected by RIA and only slightly detectable with RRA; however, high concentrations of benzylfentanyl were found by GC/MS in the same samples. Urine samples from animals injected with butyrylfentanyl showed high cross-reactivity with fentanyl antibody, giving values measured by radioimmunoassay about two times higher than those obtained by the other two methods. These findings suggest that this radioreceptor assay is well-suited as an initial assay for the detection of active analogs of fentanyl in urine and correlates well with other techniques in the analysis of fentanyl; however, there is substantial disagreement between techniques in the quantitation of fentanyl analogs.
authors.affiliation: Department of Pharmacology and Toxicology, University of Utah, Salt Lake City 84112.
authors.forename: M E
authors.initials: ME
authors.lastname: Alburges
authors.forename: G R
authors.initials: GR
authors.lastname: Hanson
authors.forename: J W
authors.initials: JW
authors.lastname: Gibb
authors.forename: C O
authors.initials: CO
authors.lastname: Sakashita
authors.forename: D E
authors.initials: DE
authors.lastname: Rollins
mesh_terms: D000700:Analgesics / Q000652:urine; D000818:Animals; D000906:Antibodies; D001522:Behavior, Animal / Q000187:drug effects; D005283:Fentanyl / Q000031:analogs & derivatives* / Q000652:urine; D008401:Gas Chromatography-Mass Spectrometry; D008297:Male; D008566:Membranes / Q000378:metabolism / Q000648:ultrastructure; D011863:Radioimmunoassay / Q000379:methods; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000032:analysis*; D017450:Receptors, Opioid, mu; D013997:Time Factors; D014316:Tritium
chemical_list: D000700:Analgesics; D000906:Antibodies; D011957:Receptors, Opioid; D017450:Receptors, Opioid, mu; D014316:Tritium; C075895:benzylfentanyl; C031638:alpha-methylfentanyl; C030592:3-methylfentanyl; D005283:Fentanyl