Postmortem Fluid and Tissue Concentrations of THC, 11-OH-THC and THC-COOH.

Marijuana is the most commonly abused illicit drug worldwide. Marijuana is used for its euphoric and relaxing properties. However, marijuana use has been shown to result in impaired memory, cognitive skills and psychomotor function. The Federal Aviation Administration's Civil Aerospace Medical Institute conducts toxicological analysis on aviation fatalities. Due to severe trauma associated with aviation accidents, blood is not always available; therefore, the laboratory must rely on specimens other than blood for toxicological analysis in ~30-40% of cases. However, the postmortem distribution of cannabinoids has not been well characterized. The purpose of this research is to evaluate the distribution of Δ9-tetrahydrocannabinol (THC), and its metabolites, 11-hydroxy-tetrahydrocannabinol (11-OH-THC) and THC-COOH, in postmortem fluid and tissue specimens from 11 fatal aviation accident cases (2014-2015) previously found positive for cannabinoids. Specimens evaluated, when available, included: blood, urine, vitreous humor, liver, lung, kidney, spleen, muscle, brain, heart and bile. We developed and validated (following SWGTOX guidelines) a sensitive and robust method using solid-phase extraction and liquid chromatography-tandem mass spectrometry to identify and quantify THC, 11-OH-THC and THC-COOH in postmortem fluids and tissues. The method readily identified and quantified these cannabinoids in postmortem fluids and tissues below 1 ng/mL. Qualitative cannabinoid results within each case were comparable between blood and non-blood specimens. However, there was no consistent distribution of the cannabinoids between blood and any other fluids or tissues. Therefore, while quantitative interpretation of non-blood postmortem fluid and tissues samples is not prudent, a majority of the non-blood specimens tested could be suitable alternative/supplemental choices for qualitative cannabinoid detection.

False carbamazepine positives due to 10,11-dihydro-10-hydroxycarbamazepine breakdown in the GC-MS injector port.

During the investigation of aviation accidents, postmortem specimens from accident victims are submitted to the Federal Aviation Administration's Civil Aerospace Medical Institute (CAMI) for toxicological analysis. A case recently received by CAMI screened positive for the anticonvulsant medication carbamazepine (CBZ; Tegretol(®)) by gas chromatography-mass spectrometry (GC-MS). The CBZ found during this routine screening procedure was subsequently confirmed using a CBZ-specific GC-MS procedure. It was later discovered that the accident victim had been prescribed oxcarbazepine (OXCBZ; Trileptal(®)). OXCBZ is structurally similar to CBZ and is metabolized by cytosolic enzymes in the liver to an active metabolite, 10,11-dihydro-10-hydroxycarbamazepine (DiCBZ). It was determined that the CBZ initially found in this case was present due to the thermal breakdown of DiCBZ in the GC-MS injector port. In the current study, this conversion was investigated and the percentage of CBZ formed at various injector port temperatures was determined. Additionally, these three compounds were quantified in nine fluid and tissue specimens from the case in question. Liquid chromatography-mass spectrometry was also incorporated to further demonstrate the absence/presence of CBZ in these samples.

Analysis of sertraline in postmortem fluids and tissues in 11 aviation accident victims.

Sertraline (Zoloft) is a selective serotonin reuptake inhibitor that is a commonly prescribed drug for the treatment of depression, obsessive-compulsive disorder, panic disorder, social anxiety disorder, premenstrual dysphoric disorder and post-traumatic stress disorder. Although the use of sertraline is relatively safe, certain side effects may negatively affect a pilot's performance and become a factor in an aviation accident. The authors' laboratory investigated the distribution of sertraline and its primary metabolite, desmethylsertraline, in various postmortem tissues and fluids obtained from 11 fatal aviation accident cases between 2001 and 2004. Eleven specimen types were analyzed for each case, including blood, urine, vitreous humor, liver, lung, kidney, spleen, muscle, brain, heart and bile. Human specimens were processed utilizing solid-phase extraction, followed by characterization and quantitation employing gas chromatography-mass spectrometry. Whole blood sertraline concentrations obtained from these 11 cases ranged from 0.005 to 0.392 µg/mL. The distribution coefficients of sertraline, expressed as specimen/blood ratio, were as follows: urine, 0.47 ± 0.39 (n = 6); vitreous humor, 0.02 ± 0.01 (n = 4); liver, 74 ± 59 (n = 11); lung, 67 ± 45 (n = 11); kidney, 7.4 ± 5 (n = 11); spleen, 46 ± 45 (n = 10); muscle, 2.1 ± 1.3 (n = 8); brain, 22 ± 14 (n = 10); heart, 9 ± 7 (n = 11); and bile, 36 ± 26 (n = 8). Postmortem distribution coefficients obtained for sertraline had coefficients of variation ranging from 47-99%. This study suggests that sertraline likely undergoes significant postmortem redistribution.

The postmortem distribution of vardenafil (Levitra) in an aviation accident victim with an unusually high blood concentration.

Vardenafil (Levitra) is one of the most widely prescribed treatments for erectile dysfunction. This report presents a rapid and reliable method for the identification and quantification of vardenafil in postmortem fluids and tissues, applies this method to a postmortem case, and describes the distribution of vardenafil in various fluids and tissues. This procedure utilizes sildenafil-d8, which is structurally closely related to vardenafil, as an internal standard for more accurate and reliable quantitation. The method incorporates solid-phase extraction and liquid chromatography-tandem mass spectrometry (MS) and MS-MS-MS utilizing an atmospheric pressure chemical ionization ion trap MS in the positive chemical ionization mode. Solid-phase extraction proved to be exceptionally efficient providing recoveries that ranged from 94% to 97%. The limit of detection for vardenafil was determined to be 0.19 ng/mL. The linear dynamic range for this compound was 0.39-200 ng/mL. This method was successfully applied to postmortem fluid and tissue specimens obtained from an aviation accident victim. The distribution of vardenafil in various fluids and tissues and the unusually high concentration of vardenafil in the victim's blood are examined.

The distribution of fluoxetine in human fluids and tissues.

Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) that was introduced in 1986. Certain side effects of this medication-drowsiness, dizziness, abnormal vision, diarrhea, and headache-could affect pilot performance and become a factor in an aviation accident. Our laboratory has determined the distribution of fluoxetine and its desmethyl metabolite, norfluoxetine, in various postmortem tissues and fluids from 10 fatal aviation accident cases. When available, 11 specimen types were analyzed for each case, including blood, urine, vitreous humor, bile, liver, kidney, skeletal muscle, lung, spleen, heart muscle, and brain. Blood fluoxetine concentrations in these 10 cases ranged from 21 to 1480 ng/mL. The distribution coefficients for both fluoxetine and norfluoxetine, expressed as specimen/blood ratios, were determined. The distribution coefficients for fluoxetine were determined to be 0.9 +/- 0.4 for urine, 0.10 +/- 0.03 for vitreous humor, 9 +/- 1 for bile, 38 +/- 10 for liver, 60 +/- 17 for lung, 9 +/- 3 for kidney, 20 +/- 5 for spleen, 2.2 +/- 0.3 for muscle, 15 +/- 3 for brain, and 10 +/- 2 for heart. To our knowledge, this is the first report presenting the distribution of fluoxetine in humans at therapeutic concentrations.

Gas chromatographic-mass spectrometric differentiation of atenolol, metoprolol, propranolol, and an interfering metabolite product of metoprolol.

Over a 10-year period, 1993-2002, Federal Aviation Administration identified 50 pilot fatalities involving atenolol, metoprolol, and propranolol, which is consistent with the fact that these drugs have been in the lists of the top 200 drugs prescribed in the U.S. In a few of the 50 pilot fatality cases, initial analysis suggested the presence of atenolol and metoprolol. However, there was no medical history with these cases supporting the use of both drugs. Therefore, atenolol, metoprolol, and/or propranolol, with their possible metabolite(s), were re-extracted from the selected case specimens, derivatized with pentafluoropropionic anhydride (PFPA), and analyzed by gas chromatography-mass spectrometry (GC-MS). The MS spectra of these three antihypertensives and a metoprolol metabolite are nearly identical. All of the PFPA derivatives had baseline GC separation, with the exception of a metoprolol metabolite product, which co-eluted with atenolol. There were four primary mass fragments (m/z 408, 366, 202, and 176) found with all of the PFPA-beta-blockers and with the interfering metabolite product. However, atenolol has three unique fragments (m/z 244, 172, and 132), metoprolol has two unique fragments (m/z 559 and 107), propranolol has four unique fragments (m/z 551, 183, 144, and 127), and the metoprolol metabolite product has two unique fragments (m/z 557 and 149). These distinctive fragments were further validated by using a computer program that predicts logical mass fragments and performing GC-MS of deuterated PFPA-atenolol and PFPA-propranolol and of the PFPA-alpha-hydroxy metabolite of metoprolol. By using the unique mass fragments, none of the pilot fatality cases were found to contain more than one beta-blocker. Therefore, these mass ions can be used for differentiating and simultaneously analyzing these structurally similar beta-blockers in biological samples.

Ethanol formation in unadulterated postmortem tissues.

During the investigation of aviation accidents, postmortem samples obtained from fatal accident victims are submitted to the FAA's Civil Aerospace Medical Institute (CAMI) for toxicological analysis. During toxicological evaluations, ethanol analysis is performed on all cases. Many species of bacteria, yeast, and fungi have the ability to produce ethanol and other volatile organic compounds in postmortem specimens. The potential for postmortem ethanol formation complicates the interpretation of ethanol-positive results from accident victims. Therefore, the prevention of ethanol formation at all steps following specimen collection is a priority. Sodium fluoride is the most commonly used preservative for postmortem specimens. Several studies have been published detailing the effectiveness of sodium fluoride for the prevention of ethanol formation in blood and urine specimens; however, our laboratory receives blood or urine in approximately 70% of cases. Thus, we frequently rely on tissue specimens for ethanol analysis. The postmortem tissue specimens received by our laboratory have generally been subjected to severe trauma and may have been exposed to numerous microbial species capable of ethanol production. With this in mind, we designed an experiment utilizing unadulterated tissue specimens obtained from aviation accident victims to determine the effectiveness of sodium fluoride at various storage temperatures for the prevention of microbial ethanol formation. We found that without preservative, specimens stored at 4 degrees C for 96 h showed an increase in ethanol concentration ranging from 22 to 75 mg/hg (average 42 +/- 15 mg/hg). At 25 degrees C, these same specimens showed an increase ranging from 19 to 84 mg/hg (average 45 +/- 22 mg/hg). With the addition of 1.00% sodium fluoride, there was no significant increase in ethanol concentration at either temperature.