Journal of analytical toxicology
-
A simple, sensitive, and reproducible liquid chromatography-tandem mass spectrometry method has been developed and validated for the quantification of the antipsychotic drug olanzapine in whole blood using dibenzepine as internal standard (IS). After acidic methanol-induced protein precipitation of the whole blood samples, olanzapine and IS were chromatographed on a reversed-phase Zorbax Extend-C(18)-column at pH 9.0. Quantification was performed on a triple-quadrupole mass spectrometer employing electrospray ionization technique operating in multiple reaction monitoring and positive ion mode. ⋯ An LOQ of 0.005 mg/kg olanzapine in whole blood was achieved. Inter- and intraday precision were less than 11% within concentrations from 0.01 to 0.50 mg/kg, and the accuracy ranged from 85 to 115%. The method was subsequently applied to 27 authentic samples, of which 20 were postmortem blood samples, from forensic investigations.
-
A rapid, sensitive, and specific method was developed and validated using ultra-performance liquid chromatography- tandem mass spectrometry (UPLC-MS-MS) for simultaneous determination of clozapine and its major metabolite norclozapine in human serum. The compounds were extracted from serum by a single step protein precipitation and analyzed using a UPLC-triple-quadrupole detection (TQD) system. Separation of compounds was achieved on a BEH C18 (50 mm x 2.1 mm, 1.7 microm) analytical column using methanol and water (both containing 0.2% ammonium hydroxide) as the mobile phase at a flow rate of 0.40 mL/min. ⋯ Intra-assay CVs (n = 6, 20 days) were 0.61-1.26% and 1.62-2.21% for clozapine and norclozapine, respectively. The extraction recoveries were larger than 95% for both clozapine and norclozapine. The method was applied to the quantification of clozapine and norclozapine in the sera of schizophrenic patients, and the data revealed that the concentrations of two compounds varied significantly in the patients treated with clozapine.
-
Comparative Study
Comparison of drugs of abuse detection in meconium by EMIT II and ELISA.
The results of meconium specimens and fortified samples screened for drugs of abuse by both enzyme multiplied immunoassay technique (EMIT((R) )II) and enzyme-linked immunosorbent assay (ELISA) methods were compared. The sample preparation for the ELISA screen was a simple buffer extraction versus a lengthy and more laborious sample preparation procedure for the EMIT II screen. The ELISA method was automated using a TECAN Genesis. ⋯ Specificity of the ELISA assay was slightly better for PCP and opioids. EMIT II appears to be more sensitive for the detection of barbiturates and benzodiazepines. The ELISA method reduced turnaround time by 50% compared to the EMIT II method.
-
Case Reports
Relationship between serum glycolate and falsely elevated lactate in severe ethylene glycol poisoning.
In the setting of ethylene glycol (EG) poisoning, a falsely elevated serum lactate concentration is suggested to be an assay cross-reaction with glycolate, but a concentration-dependent relationship has never been identified. We correlate serum lactate and glycolate concentrations in a case of severe EG poisoning. Serial EG [by gas chromatography (GC)], glycolate (derivatized to methyl glycolate, analysis by GC), and lactate (both enzymatic spectrophotometry and GC) concentrations were correlated at five time points. ⋯ The mean lactate/glycolate conversion factor was 2.58 +/- 0.95. We demonstrate the linear correlation between falsely elevated serum lactate and glycolate concentrations in a case of severe EG poisoning. Our data provide further support to the belief that the lactate assay may cross-react with glycolate in EG poisoning.
-
Etomidate is a commonly used anesthetic agent often utilized to induce anesthesia as it has a short half-life and allows for central nervous system depression without causing major cardiovascular disturbances, making it one of the preferred medications for trauma and hemodynamically unstable patients. Thus, etomidate is commonly found during a postmortem drug screen conducted for medicolegal reasons. ⋯ We report of a case of suicide by etomidate with concentrations of 0.40 mg/L in the femoral blood, 0.46 mg/L in the bile, and 0.30 mg/L in the vitreous with a blood alcohol content of 0.119 g/dL. For comparison, we identified two cases in which etomidate was administered during resuscitation after trauma with levels of 0.05 mg/L and < 0.026 mg/L, respectively.