No abstract

In the last few years, significant developments have occurred on the key issues involved in oral fluid drug testing. New pharmacokinetic studies have been conducted, optimal cutoffs have been proposed, and new studies have examined the correlation between oral fluid drug concentrations and impairment. Recent studies (eg, the discovery of the presence of THC-COOH in oral fluid) can contribute to solve the issue of false-positive results caused by passive exposure to marijuana. Reliable point-of-care drug testing is still problematic, especially for cannabinoids and benzodiazepines. To date, there is no device that allows both reliable and practical point-of-care testing. The importance of liquid chromatography- tandem mass spectrometry in confirmation analysis has increased over the last several years. It can be expected that this trend will continue because the low sample volumes make simultaneous detection of different drug classes with limited sample preparation necessary. Literature on proficiency testing to ensure reliability and comparability of results is limited. Oral fluid has become an important sample type in driving under the influence research, and the first legal random drug testing program in oral fluid since 2004 has been organized in Victoria. It can be expected that the role of oral fluid as an alternative matrix will keep increasing in the future.

Adenosine-secreting cellular brain implants constitute a promising therapeutic approach for the treatment of epilepsy. To engineer neural stem cells for therapeutic adenosine delivery, a reliable and fast analytical method is necessary to quantify cell-based adenosine release. Here we describe the development, optimization and validation of adenosine measurement using liquid chromatography -atmospheric pressure chemical ionization -tandem mass spectrometry (LC-APCI-MS/MS). LC-MS/MS in positive ion mode used selected reaction monitoring at m/z of 268.2/136.1 and 302.2/170.0 for adenosine and the internal standard, respectively. The bias was within 15% of the nominal value and evaluation of precision showed a relative standard deviation lower than 15% for all measured concentrations. The lower limit of quantification of adenosine was 15.6 ng/ml. Freeze and thaw stability and processed sample stability also fulfilled the acceptance criteria. Evaluation of the matrix effect showed that the method is not affected by relative matrix effects. The major advantages of this method are the absence of an extraction phase and the combination of the high selectivity and sensitivity characteristic for the LC-MS/MS technique, with a short run time of 4.5 min. These results demonstrate that this method is a useful tool to measure adenosine concentrations in culture medium released from stem cells in vitro.

No abstract

There is a need for a reliable rapid on-site oral fluid test that can be used in police controls to detect impaired drivers. We evaluated the Varian OralabA (R) 6 and collected two oral fluid samples from 250 subjects, one with the Varian OralabA (R) 6 and one with the StatSure (TM) SalivaaEuro cent Sampler (TM). The OralabA (R) 6 can detect six drug types: amphetamines, methamphetamine, cocaine, opiates, delta9-tetrahydrocannabinol (THC), and phencyclidine (PCP). On-site results were obtained within 10 to 15 min. The sample collected with StatSure (TM) was analyzed using liquid chromatography-tandem mass spectrometry after liquid-liquid extraction and these results were used as a reference to determine prevalence, sensitivity, and specificity. Two cut-off values were used in the evaluation. The Varian cut-off values were: amphetamine 50 ng/mL, cocaine 20 ng/mL, opiates 40 ng/mL, and THC 50 ng/mL. The DRUID cut-offs were: amphetamine 25 ng/mL, cocaine 20 ng/mL, opiates 20 ng/mL, and THC 1 ng/mL. Applying the first cut-offs, prevalence, sensitivity, and specificity were: amphetamine 10%, 76%, 100%; cocaine 23%, 34%, 100%; opiates 38%, 83%, 94%; and THC 18%, 41%, 99%. The DRUID cut-off values gave the following results: amphetamine 14%, 56%, 100%; cocaine 28%, 34%, 100%; opiates 49%, 68%, 98%, and THC 45%, 16%, 99%. The specificity of the OralabA (R) 6 is generally good. For both cut-offs, sensitivity was low for cocaine and THC. Therefore, the Varian OralabA (R) 6 test is not sensitive enough to be applied during roadside police controls