title: Development of a homogeneous immunoassay for the detection of zolpidem in urine.
abstract: Sleep disorders are common conditions that affect about 40 million people in the U.S every year, the most common of which is insomnia, which is characterized by difficulty falling or staying asleep. Zolpidem (Ambien) is a non-benzodiazepine prescription drug that is used to treat insomnia and is often preferred over the commonly used benzodiazepines due to a lesser side effect profile. This is because the non-benzodiazepine binding is more selective to GABA-A receptors versus the non-selective binding of benzodiazepines. With the increasing popularity of non-benzodiazepines, drug abuse and driving-while-impaired cases involving sleep-inducing drugs have risen. Therefore, a highly sensitive and rapid homogeneous immunoassay (EMIT-type assay) has been developed for the detection of zolpidem in urine. The zolpidem antibody is highly specific and does not cross-react with other newer sleep aids such as zopiclone and zaleplon. This assay has a detection limit of 5 ng/mL for zolpidem in urine. Further evaluation of this assay using liquid chromatography-tandem mass spectrometry (LC-MS-MS) analysis of authentic urine samples demonstrated that the accuracy of the assay is greater than 90%. Because this assay is designed to measure the non-conjugated drug in urine, it resulted in simplification for gas chromatography-MS or LC-MS-MS confirmation methods that do not require urine hydrolysis before solid-phase extraction or liquid-liquid extraction.
authors.affiliation: Immunalysis Corporation, Pomona, California 91767, USA.
authors.forename: Kim
authors.initials: K
authors.lastname: Huynh
authors.forename: Guohong
authors.initials: G
authors.lastname: Wang
authors.forename: Christine
authors.initials: C
authors.lastname: Moore
authors.forename: Rehka
authors.initials: R
authors.lastname: Barhate
authors.forename: Cynthia
authors.initials: C
authors.lastname: Coulter
authors.forename: Warren
authors.initials: W
authors.lastname: Rodrigues
authors.forename: Philip
authors.initials: P
authors.lastname: Catbagan
authors.forename: James
authors.initials: J
authors.lastname: Soares
mesh_terms: D000081:Acetamides / Q000276:immunology / Q000652:urine; D053961:Azabicyclo Compounds / Q000276:immunology / Q000652:urine; D002851:Chromatography, High Pressure Liquid; D003429:Cross Reactions; D017248:Enzyme Multiplied Immunoassay Technique; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000276:immunology / Q000652:urine*; D010879:Piperazines / Q000276:immunology / Q000652:urine; D011237:Predictive Value of Tests; D011725:Pyridines / Q000008:administration & dosage / Q000276:immunology / Q000652:urine*; D011743:Pyrimidines / Q000276:immunology / Q000652:urine; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D015813:Substance Abuse Detection / Q000379:methods*; D053719:Tandem Mass Spectrometry; D000077334:Zolpidem
chemical_list: D000081:Acetamides; D053961:Azabicyclo Compounds; D006993:Hypnotics and Sedatives; D010879:Piperazines; D011725:Pyridines; D011743:Pyrimidines; C515050:zopiclone; D000077334:Zolpidem; C085665:zaleplon