Tissue distribution of quetiapine in 20 cases in Virginia

Abstract

Quetiapine fumarate (Seroquel®) is a dibenzothiazepine psychotropic agent that was introduced in 1997 for treating psychoses. Quetiapine is being found with increasing frequency in postmortem cases in Virginia. We report the postmortem results and histories of 20 quetiapine cases from the Office of the Chief Medical Examiner in Virginia covering the period 1999 through 2004. Quetiapine was extracted from blood using a basic drug solid-phase extraction (SPE) and identified by full scan electron impact gas chromatography-mass spectrometry (GC-MS). Quetiapine quantification was accomplished by forming the trimethylsilyl derivative with bis(trimethylsilyl)trifluoracetamide/ trimethylchlorosilane and using selected ion monitoring GC-MS. The quetiapine trimethylsilyl derivative ions acquired were m/z 210, 239, and 322. Methapyrilene was the internal standard, and ions m/z 97 and 58 were monitored. The method was linear from 0.1 to 5.0 mg/L with a limit of quantitation of 0.1 mg/L. The quetiapine mean and range of concentrations found in each tissue are as follows: peripheral blood, 7.7 mg/L (0.14-37 mg/L, n = 17); heart blood, 23.63 mg/L (0.53-76 mg/L, n = 4); liver liver, 91 mg/Kg (1.1-510 mg/Kg, , n = 19); bile, 44 mg/L (6.0-96 mg/L, n = 4); urine, 15 mg/L (1.9-37 mg/L, n = 8); gastric, 897 mg total (3.5-3960 mg, n = 7); and vitreous, 1.4 mg/L (0.2-3.2 mg/L, n = 5). The average of all blood concentrations in 18 cases in which quetiapine contributed to the cause of death was 7.95 mg/L (0.4-76 mg/L). The manner of death in 13 of those cases was suicide, two were undetermined, and three were accidents. In two cases in which quetiapine was an incidental finding, the blood concentrations were 0.14 and 1.0 mg/L. Quetiapine and other toxicological findings are presented with the cause and manner of death indings to assist in interpreting future quetiapine findings in postmortem samples.