title: Comparison of methaqualone excretion patterns using Abuscreen ONLINE and EMIT II immunoassays and GC/MS.
abstract: A study was performed to compare the ONLINE and EMIT II immunoassays with gas chromatographic/mass spectrometric (GC/MS) analysis of methaqualone metabolites on urine using samples obtained from a clinical study. Urine was collected over a 72 h period from six healthy adults (4 male, 2 female) after oral dosing with 200 mg methaqualone (MTQ). Each urine sample was analyzed by ONLINE and EMIT II. The samples were then analyzed by GC/MS, hydrolyzed with beta-glucuronidase and again analyzed by GC/MS. Both immunoassays showed greater than 600 ng/ml concentrations of drug in each sample by the second void and remained highly positive for the rest of the 72 h. Unhydrolyzed samples analyzed by GC/MS showed both low concentrations of MTQ as well as its five major hydroxylated metabolites. The hydrolyzed samples analyzed by GC/MS showed high concentrations of the hydroxylated metabolites with the 2'-hydroxy and 3'-hydroxy metabolites being present at the highest concentrations, the 4'-hydroxy metabolite at a lower amount and the 6-hydroxy and 2-hydroxy metabolites at the lowest concentrations. The GC/MS data coupled with the antibody cross-reactivity data indicate that the major species in clinical samples that cross-react in both immunoassays are the conjugated forms of the hydroxylated metabolites of MTQ. Therefore when confirming by GC/MS after an immunoassay screen it would be prudent to confirm for the major hydroxylated metabolites as glucuronides of MTQ instead of the parent drug.
authors.affiliation: Roche Diagnostic Systems, Somerville, NJ 08876, USA.
authors.forename: C
authors.initials: C
authors.lastname: Brenner
authors.forename: R
authors.initials: R
authors.lastname: Hui
authors.forename: J
authors.initials: J
authors.lastname: Passarelli
authors.forename: R
authors.initials: R
authors.lastname: Wu
authors.forename: R
authors.initials: R
authors.lastname: Brenneisen
authors.forename: K
authors.initials: K
authors.lastname: Bracher
authors.forename: M A
authors.initials: MA
authors.lastname: ElSohly
authors.forename: V D
authors.initials: VD
authors.lastname: Ghodoussi
authors.forename: S J
authors.initials: SJ
authors.lastname: Salamone
mesh_terms: D000328:Adult; D003429:Cross Reactions; D017248:Enzyme Multiplied Immunoassay Technique; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000378:metabolism / Q000652:urine*; D007118:Immunoassay; D008297:Male; D008702:Methaqualone / Q000008:administration & dosage / Q000378:metabolism / Q000652:urine*; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D006993:Hypnotics and Sedatives; D008702:Methaqualone