The incidence of Zolpidem use in suspected DUI drivers in Miami-Dade Florida: a comparative study using immunalysis Zolpidem ELISA KIT and gas chromatography-mass spectrometry screening.

In 1993, Zolpidem (Ambien), a non-benzodiazepine hypnotic agent, was approved for use in the United States for the short-term treatment of insomnia. Zolpidem has a rapid onset of action and short elimination half-life, rendering it ideal as a sleep aid. The objective of this study was to evaluate, and retrospectively compare, the use of the Immunalysis ELISA kit and gas chromatograpy-mass spectrometry (GC-MS) to screen blood/urine specimens for zolpidem. In addition, results for the incidence of zolpidem in suspected DUI drivers in 2007 are compared to previous years' data. The ELISA kit was evaluated for cross-reactivity with zaleplon and zopiclone and zolpidem metabolite I. Urine samples (n = 100) and blood samples (n = 100) were selected from specimens received into the DUI laboratory in 2007 and were screened via the Immunalysis Zolpidem ELISA kit and on GC-MS in full EI scan mode following an alkaline liquid-liquid extraction. Results show 5% of the urine and blood samples screened positive for zolpidem using the ELISA kits, and all 5% confirmed positive for zolpidem using GC-MS. The ELISA kit demonstrated no cross-reactivity to zaleplon or zopiclone at a spiked urine concentration of 1000 ng/mL. Ten cases of suspected DUI drivers in 2007 confirmed positive for zolpidem by ELISA and GC-MS in blood/urine, a higher incidence rate than in the previous years. Because of the low percentage elimination of the parent compound in urine, a screening method for the detection of the main metabolite of zolpidem may be needed for better detection of drug impairment driving due to zolpidem.

Zolpidem urine excretion profiles and cross-reactivity with ELISA(®) kits in subjects using Zolpidem or Ambien(®) CR as a prescription sleep aid.

Zolpidem, a Schedule IV controlled substance under the Federal Controlled Substance Act, has a rapid onset of action and short elimination half-life, rendering it ideal as a sleep aid. The crossreactivity of two zolpidem ELISA kits was investigated using patients taking a known administration of zolpidem. Subjects provided urine samples before, 30 min after their prescribed dose, and upon waking. Specimens were screened for zolpidem by ELISA (Immunalysis and Neogen) and then confirmed and quantitated for zolpidem using gas chromatography-mass spectrometry (GC-MS) confirmation in select ion monitoring mode. All samples were measured for creatinine and corrected accordingly. The ELISA screening results demonstrated that all samples, except one, screened positive by ELISA using both kits, even when the GC-MS data found no zolpidem in the patient's urine sample. The maximum concentrations of zolpidem ranged from 15 to 120 ng/mg creatinine. Two of the patients showed zolpidem concentrations of 10 ng/mg creatinine or above after 20 h post dose. The high variability and concentration range seen in these patients, all on similar doses, suggest wide variability in the metabolism of zolpidem.

13C-Isotope ratio mass spectrometry as a potential tool for the forensic analysis of white architectural paint: a preliminary study.

Paints have a dual role in society, to protect materials from environmental agents such as ultraviolet light, moisture and oxygen, and to make painted materials look more attractive. Variability in paint samples is often due to binder and pigment type within the sample. The most common resin used in decorative paints is drying oil alkyd resin, which incorporates soybean oil and vinyl acrylic based latexes. Traditional analytical methods used by forensic scientists may be able to say whether two paint samples are indistinguishable but cannot conclusively say that they both originate from the same source. To find out if isotopic composition can provide an added dimension of information, 28 different white architectural paints were analysed for (13)C abundance using isotope ratio mass spectrometry. In addition, variations in application, drying time and thickness were also investigated to assess the discriminatory power of (13)C data from white paints with an unknown history. Preliminary results indicate that this method could aid screening of paint samples.