Summary statistics for drug concentrations in post‐mortem femoral blood representing all causes of death

Concentration distributions for 183 drugs and metabolites frequently found in post‐mortem (PM) femoral venous blood were statistically characterized based on an extensive database of 122 234 autopsy cases investigated during an 18‐year period in a centralized laboratory. The cases represented all causes of death, with fatal drug poisonings accounting for 8%. The proportion of males was 74% with a median age of 58 years compared with 26% females with a median age of 64 years. In 36% of these cases, blood alcohol concentration was higher than or equal to 0.2‰, the median being 1.6‰. The mean, median, and upper percentile (90th, 95th, 97.5th) drug concentrations were established, as the median PM concentrations give an idea of the “normal” PM concentration level, and the upper percentile concentrations indicate possible overdose levels. A correspondence was found between subsets of the present and the previously published PM drug concentrations from another laboratory that grouped cases according to the cause of death. Our results add to the knowledge for evidence‐based interpretation of drug‐related deaths.     

Drug concentrations in post‐mortem specimens

A meta‐analysis of drug concentrations in post‐mortem specimens is presented. The analysis involved 50 commonly used drugs and their concentrations in femoral blood, other blood (such as cardiac blood), vitreous humor, muscle, liver, kidney, brain, heart, lung, spleen, and bile. A total of 10 993 analytical results from 5375 post‐mortem cases in 388 studies were gathered and the ratios of drug concentrations in tissue material to median femoral blood concentrations were calculated. Analytical results from the laboratory's own database (years 2000–2018) were also included. The results show that the variation of ratios between post‐mortem specimens and femoral blood is highly compound dependent. This database can be utilized in interpretation of toxicological results in cases where femoral blood is not available. The specimens with similar concentrations as in femoral blood were vitreous humor, muscle, and other blood, such as cardiac blood, and the highest concentrations were generally measured from liver and bile. For these reasons we suggest the following order for biological specimens to be used for a quantitative toxicological analysis in cases where femoral blood is not available: 1. other blood, 2. muscle, 3. vitreous humor, 4. brain, 5. heart, 6. spleen, 7. kidney, 8. liver, and 9. bile.     

Validation of a fully automated solid‐phase extraction and ultra‐high‐performance liquid chromatography–tandem mass spectrometry method for quantification of 30 pharmaceuticals and metabolites in post‐mortem blood and brain samples

In this study, we present the validation of an analytical method capable of quantifying 30 commonly encountered pharmaceuticals and metabolites in whole blood and brain tissue from forensic cases. Solid‐phase extraction was performed by a fully automated robotic system, thereby minimising manual labour and human error while increasing sample throughput, robustness, and traceability. The method was validated in blood in terms of selectivity, linear range, matrix effect, extraction recovery, process efficiency, carry‐over, stability, precision, and accuracy. Deuterated analogues of each analyte were used as internal standards, which corrected adequately for any inter‐individual variability in matrix effects on analyte accuracy and precision. The lower limit of quantification (LLOQ) spanned from 0.0008 to 0.010 mg/kg, depending on the analyte, while the upper LOQ ranged between 0.40 and 2.0 mg/kg. Thus, the linear range covered both therapeutic and toxic levels. The method showed acceptable accuracy and precision, with accuracies ranging from 80 to 118% and precision below 19% for the majority of the analytes. Linear range, matrix effect, extraction recovery, process efficiency, precision, and accuracy were also tested in brain homogenate and the results agreed with those from blood. An additional finding was that the analyte concentrations in brain samples could be quantified by calibration curves obtained from spiked blood samples with acceptable precision and accuracy when using deuterated analogues of each analyte as internal standards. This method has been successfully implemented as a routine analysis procedure for quantification of pharmaceuticals in both blood and brain tissue since 2015.     

Rapid determination of quetiapine in blood by gas chromatography–mass spectrometry. Application to post‐mortem cases

A simple, fast and sensitive method for the determination of quetiapine in human blood has been developed and validated. The method involved a basic liquid–liquid extraction procedure and subsequent analysis by gas chromatography–mass spectrometry, previous derivatization with bis(trimethylsilyl)‐trifluoro‐acetamide and chorotrimethylsilane (99 : 1). The methods of validation included linearity with a correlation coefficient > 0.99 over the range 0.02–1 µg ml^–1, intra‐ and interday precision (always < 12%) and accuracy (mean relative error always < 12%) to meet the bioanalytical acceptance criteria. The limit of detection was 0.005 µg ml^–1. The procedure was further applied to post mortems from the Institute of Legal Medicine, University of Santiago de Compostela. Copyright © 2013 John Wiley & Sons, Ltd.     

Studies on drug metabolism by fungi colonizing decomposing human cadavers. Part II: biotransformation of five model drugs by fungi isolated from post‐mortem material

The present study investigated the in vitro metabolic capacity of 28 fungal strains isolated from post‐mortem material towards five model drugs: amitriptyline, metoprolol, mirtazapine, promethazine, and zolpidem. Each fungal strain was incubated at 25 °C for up to 120 h with each of the five models drugs. Cunninghamella elegans was used as positive control. Aliquots of the incubation mixture were centrifuged and 50 μL of the supernatants were diluted and directly analyzed by liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) with product ion scanning. The remaining mixture was analyzed by full scan gas chromatography‐mass spectrometry (GC‐MS) after liquid‐liquid extraction and acetylation. The metabolic activity was evaluated through the total number of detected metabolites (NDM) produced in each model and fungal strains and the percentage of parent drug remaining (%RPD) after up to five days of incubation. All the tested fungal strains were capable of forming mammalian phase I metabolites. Fungi from the normal fungal flora of the human body such as Candida sp., Geotrichum candidum, and Trichosporon asahii) formed up to seven metabolites at %RPD values greater than 52% but no new fungal metabolites (NFM). In contrast, some airborne fungal strains like Bjerkandera adusta, Chaetomium sp, Coriolopsis sp., Fusarium solani and Mucor plumbeus showed NDM values exceeding those of the positive control, complete metabolism of the parent drug in some models and formation of NFM. NFM (numbers in brackets) were detected in four of the five model drugs: amitriptyline (18), metoprolol (4), mirtazapine (8), and zolpidem (2). The latter NFM are potential candidates for marker substances indicating post‐mortem fungal metabolism. Copyright © 2014 John Wiley & Sons, Ltd.     

Post‐mortem determination of insulin using chemiluminescence enzyme immunoassay: preliminary results

Insulin determination in blood sampled during post‐mortem investigation has been repeatedly asserted as being of little diagnostic value due to the rapid occurrence of decompositional changes and blood haemolysis. In this study, we assessed the feasibility of insulin determination in post‐mortem serum, vitreous humour, bile, and cerebrospinal and pericardial fluids in one case of fatal insulin self‐administration and a series of 40 control cases (diabetics and non‐diabetics) using a chemiluminescence enzyme immunoassay. In the case of suicide by insulin self‐administration, insulin concentrations in pericardial fluid and bile were higher than blood clinical reference values, though lower than post‐mortem serum concentration. Insulin concentrations in vitreous (11.50 mU/L) and cerebrospinal fluid (17.30 mU/L) were lower than blood clinical reference values. Vitreous insulin concentrations in non‐diabetic control cases were lower than the estimated detection limit of the method. These preliminary results tend to confirm the usefulness of insulin determination in vitreous humour in situations of suspected fatal insulin administration. Additional findings pertaining to insulin determination in bile, pericardial, and cerebrospinal fluid would suggest that analysis performed in post‐mortem serum and injection sites could be complemented, in individual cases, by investigations carried out in alternative biological fluids. Lastly, these results would indicate that analysis with chemiluminescence enzyme immunoassay may provide suitable data, similar to analysis with liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) and immunoradiometric assay, to support the hypothesis of insulin overdose. Copyright © 2015 John Wiley & Sons, Ltd.     

Production of human metabolites by gastrointestinal bacteria as a potential source of post‐mortem alteration of antemortem drug/metabolite concentrations

Previous studies have demonstrated that bacterial species are capable of transforming complex chemical substances. Several of these species, native to the human gastrointestinal tract, are active in postmortem decomposition. They have potential to cause biotransformations affecting compound‐to‐metabolite ratios within the human body, especially after death. Investigation of postmortem effects could supply valuable information, especially concerning compound identification and confirmation. The purpose of this research was to investigate the effects of Escherichia coli, Bacteroides fragilis, and Clostridium perfringens on diazepam and flunitrazepam in Reinforced Clostridial Medium, and to compare bacterial biotransformation products to those of human metabolism. A decrease in diazepam concentration between pre‐ and post‐incubation was observed for samples inoculated with Escherichia coli (14.7–20.2%) as well as Bacteroides fragilis (13.9–25.7%); however there was no corresponding increase in concentration for the monitored human metabolites. Flunitrazepam demonstrated a greater concentration loss when incubated with individual bacterial species as well as mixed culture (79.2–100.0%). Samples incubated with Bacteroides fragilis, Clostridium perfringens, and mixed culture resulted in nearly complete conversion of flunitrazepam. Increased 7‐aminoflunitrazepam concentrations accounted for the majority of the conversion; however discrepancies in the mass balance of the reaction suggested the possibility of a minor metabolite that was not monitored in the current analysis. These experiments served as a pilot study and proof of concept that can be adapted and applied to a realm of possibilities. Ultimately, this methodology would be ideal to study compounds that are too toxic or lethal for animal and human metabolic investigations. Copyright © 2014 John Wiley & Sons, Ltd.     

Development and validation of an ESI‐LC‐MS/MS method for simultaneous identification and quantification of 24 analytes of forensic relevance in vitreous humour,whole blood and plasma

Detection and quantification of drugs from various biological matrices are of immense importance in forensic toxicological analysis. Despite the various reported methods, development of a new method for the detection and quantification of drugs is still an active area of research. However, every method and biological matrix has its own limitation, which further encourage forensic toxicologists to develop new methods and to explore new matrices for the analysis of drugs. In this study, an electrospray ionization‐liquid chromatograph‐tandem mass spectrometry (ESI‐LC‐MS/MS) method is developed and validated for simultaneous identification and quantification of 24 drugs of forensic relevance in various body fluids, namely, whole blood, plasma and vitreous humour. The newly developed method has been validated for intra‐day and inter‐day accuracy, precision, selectivity and sensitivity. Absolute recovery shows a mean of 84.5, 86.2, and 103% in the vitreous humour, whole blood and plasma respectively, which is suitable for the screening procedure. Further, the absolute matrix effect (AME) shows a mean of 105, 96.5, and 109% in the vitreous humour, whole blood and plasma, respectively. In addition, to examine the practical utility of this method, it has been applied for screening of drugs in post‐mortem samples of the vitreous humour, whole blood and plasma collected at autopsy from ten cadavers. Experimental results show that the newly developed method is well applicable for screening of analytes in all the three matrices. Copyright © 2015 John Wiley & Sons, Ltd.     

An evaluation of the DRI‐ETG EIA method for the determination of ethyl glucuronide concentrations in clinical and post‐mortem urine

A commercial enzyme immunoassay for the qualitative and semi‐quantitative measurement of ethyl glucuronide (EtG) in urine was evaluated. Post‐mortem (n=800), and clinical urine (n=200) samples were assayed using a Hitachi 902 analyzer. The determined concentrations were compared with those obtained using a previously published liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) method for the quantification of EtG and ethyl sulfate. Using a cut‐off of 0.5 µg/ml and LC‐MS/MS limit of reporting of 0.1 µg/ml, there was a sensitivity of 60.8% and a specificity of 100% for clinical samples. For post‐mortem samples, sensitivity and specificity were 82.4% and 97.1%, respectively. When reducing the cut‐off to 0.1 µg/ml, the sensitivity and specificity were 83.3% and 100% for clinical samples whereas for post‐mortem samples the sensitivity and specificity were 90.3 % and 88.3 %, respectively. The best trade‐offs between sensitivity and specificity for LC‐MS/MS limits of reporting of 0.5 and 0.1 µg/ml were achieved when using immunoassay cut‐offs of 0.3 and 0.092 µg/ml, respectively. There was good correlation between quantitative results obtained by both methods but analysis of samples by LC‐MS/MS gave higher concentrations than by enzyme immunoassay (EIA), with a statistically significant proportional bias (P<0.0001, Deming regression) for both sample types. The immunoassay is reliable for the qualitative and semi‐quantitative presumptive detection of ethyl glucuronide in urine. Copyright © 2012 John Wiley & Sons, Ltd.     

Analysis of phenazepam and 3‐hydroxyphenazepam in post‐mortem fluids and tissues

Phenazepam is a benzodiazepine that is predominantly used clinically in the former Soviet states but is being abused throughout the wider world. This study reports the tissue distribution and concentration of both phenazepam and 3‐hydroxyphenazepam in 29 cases quantitated by liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) in a variety of post‐mortem fluids (subclavian blood, femoral blood, cardiac blood, urine, vitreous humour) and tissues (thalamus, liver and psoas muscle). In 27 cases, the cause of death was not directly related to phenazepam (preserved (fluoride/oxalate) femoral blood phenazepam concentrations 0.007 mg/L to 0.360 mg/L (median 0.097 mg/L). In two cases, phenazepam was either a contributing factor to, or the certified cause of death (preserved (fluoride/oxalate) femoral blood 0.97 mg/L and 1.64 mg/L). The analysis of phenazepam and 3‐hydroxyphenazepam in this study suggests that they are unlikely to be subject to large post‐mortem redistribution and that there is no direct correlation between tissues/fluid and femoral blood concentrations. Preliminary investigations of phenazepam stability comparing femoral blood phenazepam concentrations in paired preserved (2.5% fluoride/oxalate) and unpreserved blood show that unpreserved samples show on average a 14% lower concentration of phenazepam and we recommend that phenazepam quantitation is carried out using preserved samples wherever possible. Copyright © 2015 John Wiley & Sons, Ltd.     

丙戊酸钠联用碳青霉烯类药物血药浓度变化特点探讨

目的：探讨丙戊酸钠联用碳青霉烯类药物后引起丙戊酸钠血药浓度变化特点,为临床合理用药提供参考。方法：采用化学发光免疫分析法检测丙戊酸钠联用碳青霉烯类药物前、期间以及停用碳青霉烯类药物后的血药浓度,总结变化特点,并研究给药剂量调整与血药浓度变化情况。结果：丙戊酸钠联用碳青霉烯类药物后,美罗培南使其血药浓度下降（83.2±7.8）%,亚胺培南使其血药浓度下降（71.7±5.3）%,停用碳青霉烯类药物后,血药浓度逐渐恢复,但增加丙戊酸钠给药剂量对血药浓度变化影响不明显。结论：碳青霉烯类药物可致丙戊酸钠血药浓度显著降低,两者不宜联用,以确保临床用药安全、有效。     

Enantioselective analysis of citalopram and demethylcitalopram in human whole blood by chiral LC–MS/MS and application in forensic cases

Citalopram is one of the most frequently used antidepressants in Denmark. It is marketed as a racemic mixture (50:50) of S‐ and R‐enantiomers as well as of the S‐enantiomer alone, which is the active enantiomer named escitalopram that processes the inhibitory effects. In this study, a chiral liquid chromatography–tandem mass spectrometry (LC–MS/MS) method is developed for the measurement of citalopram and demethylcitalopram enantiomers in whole blood and is applied to forensic cases. Whole blood samples (0.10 g) were extracted with butyl acetate after adjusting the pH with 2 M NaOH. The analytes were separated on a 250 × 4.6 mm Chirobiotic V, 5 μm column by isocratic elution with methanol:ammonia:acetic acid (1000:1:1) using an ultra‐high‐pressure liquid chromatography (UHPLC) system. Quantification was performed by tandem mass spectrometry (MS/MS) using multiple reaction monitoring (MRM) in the positive mode. The total chromatographic run time was 20 min. The limit of detection (LOD) and quantification (LOQ) were 0.001 and 0.005 mg/kg of all four enantiomers, respectively. Linear behaviour was obtained for all four enantiomers from LOQ to 0.50 mg/kg blood with absolute recoveries from 71 to 80%. The method showed an acceptable precision and accuracy as the obtained coefficient of variation, and bias values were ≤16% for all enantiomers. After the validation of the method, a correlation with the racemic method was assessed and found to be acceptable. Then, the method was successfully applied to authentic blood samples from forensic investigations demonstrating that escitalopram was less frequent than citalopram among all forensic cases. Copyright © 2017 John Wiley & Sons, Ltd.     

Dosing time‐dependent effect of raloxifene on plasma plasminogen activator inhibitor‐1 concentrations in post‐menopausal women with osteoporosis

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反相高效液相色谱法测定人血浆中氟康唑的浓度及其应用

目的:建立氟康唑人血浆中药物浓度的高效液相色谱测定方法,并用于氟康唑人体药代动力学研究。方法:使用固相萃取高效液相色谱紫外检测法,样品经 Bond elut 同相萃取小柱处理。色谱柱为 Diamonsil C~(18)柱(4.6 mm×150 mm,5 μm),流动相:0.01 mol·L~(-1)磷酸二氢钾(1000 mL 0.01 mol·L~(-1)磷酸二氢钾加入200 μL三乙胺)-乙腈-甲醇(60:24:16),流速为1.0 mL·min~(-1),柱温为30℃,紫外检测波长267 nm,内标为非那西丁。结果:氟康唑血浆浓度测定方法的线性范围为0.1～9.6 μg·mL~(-1),线性关系良好(γ=0.9997),最低检测浓度为0.1μg·mL~(-1)(以 S/N>4计),方法回收率为93.7%～102.1%,日内和日间差异均小于6%。结论:本文采用的高效液相色谱紫外检测法灵敏度高、重复性好,能快速可靠地测定氟康唑血药浓度,适用于氟康唑的血药浓度监测和人体约代动力学研究。     

Rapid determination of nine barbiturates in human whole blood by liquid chromatography‐tandem mass spectrometry

A rapid, simple and sensitive liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) method was developed for the qualitative and quantitative analysis of nine barbiturates (barbital, phenobarbital, pentobarbital, amobarbital, secobarbital, thiopental, butalbital, butabarbital, and hexobarbital) in human whole blood. Barbiturates were extracted from 100 μL of human whole blood samples using a simple liquid‐liquid extraction (LLE) procedure, and detected by LC‐MS/MS. An UPLC C18 (2.1 mm × 100 mm, 1.7 µm) column was used at 40 °C for the separation and acetonitrile/water system was used as the mobile phase with gradient elution. This method showed excellent accuracy (86–111%) and precision (relative standard deviation <15%). The limits of detection (LODs) were 0.2 ng/mL for barbital and secobarbital and 0.5 ng/mL for the other barbiturates. The linearity ranged from 2 ng/mL to 2000 ng/mL, with r² > 0.99 over the range. This method achieved the separation and detection of pentobarbital and amobarbital at the same time in a convenient way. Moreover, it was both simple and sensitive for the determination of nine most commonly used barbiturate drugs, which was meaningful in the field of clinical and forensic toxicology. Copyright © 2016 John Wiley & Sons, Ltd.     

The role of apelin in central cardiovascular regulation in rats with post‐infarct heart failure maintained on a normal fat or high fat diet

Based on the available literature, it can be assumed that in cases of post‐infarct heart failure (HF) and obesity, a significant change in the central regulation of the cardiovascular system takes place with, among others, the involvement of the apelinergic system. The main objective of the present study was to clarify the role of apelin‐13 in the central regulation of the cardiovascular system in Sprague Dawley rats with HF or sham operated (SO) and fed on a normal fat (NFD) or a high fat diet (HFD). The study was divided into two parts: Part I, hemodynamic studies; and Part II, biochemical and molecular studies. The animals were subjected to the following research procedures. Part I and II: feeding NFD or HFD; experimental induction of HF or SO; Part I: intracerebroventricular (ICV) infusion of the examined substances, monitoring of mean arterial blood pressure (MABP) and heart rate (HR); Part II: venous blood and tissue samples collected. ICV infusion of apelin‐13 caused significantly higher changes in ΔMABP in the SO NFD group. No changes were noted in ΔHR in any of the studied groups. Apelin and apelin receptor (APJ) mRNA expression in the brain and adipose tissues was higher in the HF rats. HFD causes significant increase in expression of apelin and APJ mRNA in the left ventricle. In conclusion, HF and HFD appear to play an important role in modifying the activity of the central apelinergic system and significant changes in mRNA expression of apelin and APJ receptor.     

Relationship between plasma concentrations of clozapine and norclozapine and therapeutic response in patients with schizophrenia resistant to conventional neuroleptics

Rationale: Monitoring plasma clozapine concentrations may play a useful role in the management of patients with schizophrenia, but information on the relationship between the plasma levels of the drug and response is still controversial. Objective: The purpose of this study was to assess the relationship between plasma concentrations of clozapine and its weakly active metabolite norclozapine and clinical response in patients with schizophrenia resistant to conventional neuroleptics. Methods: Forty-five patients, 35 males and ten females, aged 19–65 years, were given clozapine at a dosage up to 500 mg/day for 12 weeks. Steady-state plasma concentrations of clozapine and norclozapine were measured at week 12 by a specific HPLC assay. Psychopathological state was assessed at baseline and at week 12 by using the Brief Psychiatric Rating Scale, and patients were considered responders if they showed a greater than 20% reduction in total BPRS score compared with baseline and a final BPRS score of 35 or less. Results: Mean plasma clozapine concentrations were higher in responders (n=18) than in non-responders (n=27) (472±220 versus 328±128 ng/ml, P<0.01), whereas plasma norclozapine levels did not differ between the two groups (201±104 versus 156±64 ng/ml, NS). A significant positive correlation between plasma levels and percent decrease in total BPRS score was found for clozapine (r _s=0.371, P<0.02), but not for norclozapine (r _s=0.162, NS). A cutoff value at a clozapine concentration of about 350 ng/ml differentiated responders from non-responders with a sensitivity of 72% and a specificity of 70%. At a cutoff of 400 ng/ml, sensitivity was 67% and specificity 78%. The incidence of side effects was twice as high at clozapine concentrations above 350 ng/ml compared with lower concentrations (38% versus 17%). Conclusions: These results suggest that plasma clozapine levels are correlated with clinical effects, although there is considerable variability in the response achieved at any given drug concentration. Because many patients respond well at plasma clozapine concentrations in a low range, aiming initially at plasma clozapine concentrations of 350 ng/ml or greater would require in some patients use of unrealistically high dosages and imply an excessive risk of side effects. Increasing dosage to achieve plasma levels above 350–400 ng/ml may be especially indicated in patients without side effects who failed to exhibit amelioration of psychopathology at standard dosages or at lower drug concentrations. Received: 5 May 1999 / Final version: 30 August 1999