Vitreous humor in the forensic toxicology of quetiapine and its metabolites.

PURPOSE: Τhe aim of the present study was to investigate the use of vitreous humor as an alternative biological material in forensic toxicology for the determination of quetiapine, 7-hydroxy-quetiapine, and nor-quetiapine. The distribution of these substances in vitreous humor was studied by determining and correlating their concentrations in vitreous humor with the respective concentrations in blood. METHODS: During this study, a method for the determination of these substances was developed, validated and applied to postmortem samples obtained from 16 relative forensic cases. The sample preparation procedure included the isolation of the analytes from vitreous humor and blood samples using solid-phase extraction, with Bond Elut LRC C18 columns followed by derivatization with BSTFA with 1% TMCS prior to GC/MS analysis. RESULTS: The developed method is characterized by a dynamic range of 10.0-1000.0 ng/mL (R2 ≥ 0.991) for the three substances, with a limit of detection and quantification of 3.0 and 10.0 ng/mL, respectively. Accuracy and precision were below 8.09% and 8.99%, respectively, for both biological materials, while absolute recovery for the three substances was greater than 81%. According to the results, quetiapine, 7-hydroxy-quetiapine, and nor-quetiapine are easily distributed in vitreous humor. CONCLUSION: The results of the study indicate the usefulness of vitreous humor in toxicological analysis for the determination of these substances, especially when the traditional biological materials are not available. The levels of quetiapine and its metabolites in vitreous humor as well as the vitreous humor to blood concentration ratios can provide important information for a more thorough toxicological investigation of forensic cases.

Bisphenol A correlates with fewer retrieved oocytes in women with tubal factor infertility.

PURPOSE: Serum and urinary bisphenol A (BPA) concentrations have been associated negatively with the number of retrieved oocytes after in vitro fertilization (IVF). The impact of BPA upon women with polycystic ovary syndrome (PCOS) and women with tubal factor infertility (TFI), following IVF, was investigated. To this purpose, associations among serum and urinary and follicular fluid (FF) BPA concentrations and the number of retrieved and fertilized oocytes and comparisons between pregnancy rates were evaluated. METHODS: This was a cross-sectional study conducted at a university-affiliated assisted conception unit between January and November 2019, including 93 women of reproductive age (PCOS: 45; TFI: 48) following IVF. Unconjugated FF and serum BPA concentrations and total urinary BPA concentration were measured using a novel gas chromatography-mass spectrometry method. The number of retrieved and fertilized oocytes and pregnancy rate were documented and evaluated. RESULTS: The number of oocytes retrieved from PCOS women was greater than that of 21 TFI women, independently of BMI. Lower FF BPA concentrations were found in all PCOS women and in overweight/obese PCOS compared to TFI women (0.50, 0.38, and 1.13 ng/mL, respectively). In TFI women, FF BPA concentrations correlated negatively with the number of retrieved oocytes. Serum and FF and urinary BPA concentrations did not significantly affect the number of fertilized oocytes and pregnancy rate in both groups. CONCLUSION: FF BPA concentrations were lower in all PCOS women and in overweight/obese PCOS than in TFI women. In TFI women, FF BPA concentrations correlated negatively with retrieved oocytes. Confirmation of these findings might lead to moderation of use of BPA-containing products by women undergoing IVF.

Incidence of fatalities of road traffic accidents associated with alcohol consumption and the use of psychoactive drugs: A 7-year survey (2011-2017).

Driving under the influence of alcohol and/or psychoactive substances increases the risk of severe, even fatal motor vehicle accidents. The aim of this descriptive study was to present the impact of alcohol and/or psychoactive substances on fatal road traffic accidents (RTAs) during the period 2011-2017. For this purpose, the toxicological investigation reports from the Department of Forensic Medicine and Toxicology of the University of Athens were used. In total, 1,841 (32.2%) of the autopsies conducted by the Department of Forensic Medicine and Toxicology of the National and Kapodistrian University of Athens over a 7-year period (2011-2017) were victims of fatal RTAs. Blood and urine samples were collected and analyzed for the presence of alcohol and psychoactive substances. The results were classified according to sex, age, victim (car driver, motorcyclist, pedestrian, or passenger) and the date the accident occurred (day, month and year). In total, 40.7% of the RTA-related fatalities were associated with alcohol consumption, among which 20.3% were car drivers. Of these, 87.3% were male victims. A higher frequency of RTA-related fatalities associated with a blood alcohol concentration (BAC) >110 mg/dl was encountered in younger compared with older age groups. Psychoactive substances were detected in 348 (18.9%) of the victims (cannabis in 46.6% of these, benzodiazepines in 25.9%, opiates in 16.4% and cocaine in 11.1% of these). The percentage of the RTA-related victims that had consumed alcohol in combination with other psychoactive substances was 4.5%. On the whole, the findings of this study suggest that alcohol and psychoactive substances are probably risk factors for RTA-related fatalities.

Bioanalytical LC-MS Method for the Quantification of Plasma Androgens and Androgen Glucuronides in Breast Cancer.

The physiological and pathological development of the breast is strongly affected by the hormonal milieu consisting of steroid hormones. Mass spectrometry (MS) technologies of high sensitivity and specificity enable the quantification of androgens and consequently the characterization of the hormonal status. The aim of this study is the assessment of plasma androgens and androgen glucuronides, in the par excellence hormone-sensitive tissue of the breast, through the application of liquid chromatography-mass spectrometry (LC-MS). A simple and efficient fit-for-purpose method for the simultaneous identification and quantification of dehydroepiandrosterone sulfate (DHEAS), androstenedione (A4), androsterone glucuronide (ADTG) and androstane-3α, 17ß-diol-17-glucuronide (3α-diol-17G) in human plasma was developed and validated. The presented method permits omission of derivatization, requires a single solid-phase extraction procedure and the chromatographic separation can be achieved on a single C18 analytical column, for all four analytes. The validated method was successfully applied for the analysis of 191 human plasma samples from postmenopausal women with benign breast disease (BBD), lobular neoplasia (LN), ductal carcinoma in situ and invasive ductal carcinoma (IDC). DHEAS plasma levels exhibited significant differences between LN, IDC and BBD patients (P < 0.05). Additionally, ADTG levels were significantly higher in patients with LN compared with those with BBD (P < 0.05).

Clinical and echocardiographic correlates of serum copper and zinc in acute and chronic heart failure.

AIM: Emerging evidence suggests a pathophysiological role of micronutrient dyshomeostasis in heart failure, including promotion of adverse remodeling and clinical deterioration. We sought to evaluate serum copper (Cu) and zinc (Zn) levels in acute (AHF) and chronic (CHF) heart failure. METHODS: We studied 125 patients, 71 % male, aged 69 ± 11 years, 37 % with preserved left ventricular ejection fraction (LVEF ≥40 %) (HFPEF), including 81 with AHF and 44 with CHF; 21 healthy volunteers served as controls. Serum Cu and Zn levels were determined using air-acetylene flame atomic absorption spectrophotometry. RESULTS: Serum Cu levels were significantly higher in AHF (p = 0.006) and CHF (p = 0.002) patients compared to controls after adjusting for age, gender and comorbidities, whereas they did not differ between AHF and CHF (p = 0.840). Additionally, serum Cu in patients with LVEF <40 % was significantly higher compared to both controls (p < 0.001) and HFPEF patients (p = 0.003). Serum Zn was significantly lower in AHF (p < 0.001) and CHF (p = 0.039) compared to control after adjusting for the above-mentioned variables. Moreover, serum Zn was significantly lower in AHF than in CHF (p = 0.015). In multiple linear regression, LVEF (p = 0.033) and E/e ratio (p = 0.006) were independent predictors of serum Cu in total heart failure population, while NYHA class (p < 0.001) and E/e ratio (p = 0.007) were independent predictors of serum Zn. CONCLUSION: Serum Cu was increased both in AHF and CHF and correlated with LV systolic and diastolic function. Serum Zn, in contrast, was decreased both in AHF and CHF and independently predicted by clinical status and LV diastolic function.

Stability of morphine, codeine, and 6-acetylmorphine in blood at different sampling and storage conditions.

The stability of drugs in biological specimens is a major concern during the evaluation of the toxicological results. The stability of morphine, codeine, and 6-acetyl-morphine in blood was studied after different sampling conditions: (i) in glass, polypropylene or polystyrene tubes, (ii) with addition of dipotassium ethylene diamine tetraacetic acid (K2EDTA) or sodium oxalate (Na2C2O4), and (iii) with or without the addition of sodium fluoride (NaF). Spiked blood samples were stored at two different temperatures (4 and -20°C), analyzed after different storage times and after three freeze­thaw cycles. Opiate concentrations were decreased in all conditions, but the most unstable was 6-acetyl-morphine. The addition of NaF as preservative improved the stability of opiates at all conditions studied, whereas the type of anticoagulant did not affect the stability of opiates. It was concluded that blood samples should be stored at -20°C in glass tubes containing oxalate and NaF for maximum stability.

Androgen glucuronides analysis by liquid chromatography tandem-mass spectrometry: could it raise new perspectives in the diagnostic field of hormone-dependent malignancies?

Breast and prostate constitute organs of intense steroidogenic activity. Clinical and epidemiologic data provide strong evidence on the influence of androgens and estrogens on the risk of typical hormone-dependent malignancies, like breast and prostate cancer. Recent studies have focused on the role of androgen metabolites in regulating androgen concentrations in hormone-sensitive tissues. Steroid glucuronidation has been suggested to have a prominent role in controlling the levels and the biological activity of unconjugated androgens. It is well-established that serum levels of androgen glucuronides reflect androgen metabolism in androgen-sensitive tissues. Quantitative analysis of androgen metabolites in blood specimens is the only minimally invasive approach permitting an accurate estimate of the total pool of androgens. During the past years, androgen glucuronides analysis most often involved radioimmunoassays (RIA) or direct immunoassays, both methods bearing serious limitations. However, recent impressive technical advances in mass spectrometry, and particularly in high performance liquid chromatography coupled with mass spectrometry (LC-MS/MS), have overcome these drawbacks enabling the simultaneous, quantitative analysis of multiple steroids even at low concentrations. Blood androgen profiling by LC-MS/MS, a robust and reliable technique of high selectivity, sensitivity, specificity, precision and accuracy emerges as a promising new approach in the study of human pathology. The present review offers a contemporary insight in androgen glucuronides profiling through the application of LC-MS/MS, highlighting new perspectives in the study of steroids and their implication in hormone-dependent malignancies.

Ibogaine related sudden death: a case report.

Ibogaine is a naturally occurring alkaloid derived from the roots of the rain forest shrub Tabernanthe iboga. Deaths have occurred temporarily related to the use of ibogaine. However, although not licensed as therapeutic drug, and despite evidence that ibogaine may disturb the rhythm of the heart, this alkaloid is currently used as an anti-addiction drug in alternative medicine for detoxification purposes. We report the case of a man who died suddenly 12-24 h after ibogaine use for alcohol detoxification treatment. In the autopsy liver cirrhosis and heavy fatty infiltration was found. The concentration of ibogaine was 2 mg/l. The potential risks of ibogaine use, especially for persons with pathological medical background, are discussed.

Direct urine analysis for the identification and quantification of selected benzodiazepines for toxicology screening.

A simple and rapid LC/MS method with direct injection analysis was developed and validated for the identification and quantification of ten benzodiazepines (flunitrazepam, nordiazepam, diazepam, 7-aminoflunitrazepam, flurazepam, bromazepam, midazolam, alprazolam, temazepam and oxazepam) in human urine using diazepam-d5 as internal standard (IS). The main advantage of the proposed methodology is the minimal sample preparation procedure, as diluted urine samples were directly injected into LC/MS system. Electrospray ionization in positive mode using selected ion monitoring was chosen for the identification and quantification of the analytes. The linear range was 50-1000 ng/mL for each analyte, with square correlation coefficient (r(2))≥0.981. Interday and intraday errors were found to be ≤5.72%. The LC/MS method was applied at ten real samples found initially to be positive and negative, using immunoassay technique. Finally the results were confirmed with GC/MS. The method demonstrates simplicity and fast sample preparation, accuracy and specificity of the analytes which make it suitable for replacement of immunoassay screening in urine avoiding thus false negative/false positive results. Using this method, laboratories may overcome the problem of high cost instrumentation such as LC-MS/MS by providing similar sensitivity and specificity with other methods.

A fully validated method for the simultaneous determination of 11 antidepressant drugs in whole blood by gas chromatography-mass spectrometry.

Antidepressant drugs are widely used for the treatment of depression and other psychiatric disorders and as a result they are involved in numerous clinical and forensic cases. The aim of this study was the development, optimization and validation of a simple, specific and sensitive GC/MS method for the simultaneous determination of 11 antidepressant drugs and 4 of their metabolites (amitriptyline, citalopram, clomipramine, fluoxetine, fluvoxamine, maprotiline, desmethyl-maprotiline, mirtazapine, desmethyl-mirtazapine, nortriptyline, paroxetine, sertraline, desmethyl-sertraline, venlafaxine and desmethyl-venlafaxine) in whole blood. The combination of solid-phase extraction with derivatization using heptafluorobutyric anhydride efficiently reduced matrix effect and improved sensitivity of the method. In this assay, protriptyline was used as internal standard. Absolute recovery values for all analytes were ranged from 79.2 to 102.6%. LODs and LOQs were found to be between 0.30-1.50 µg/L and 1.00-5.00 µg/L, respectively. The calibration curves were linear (R(2)≥0.990) within the range of 5.00-1000 µg/L for all analytes. Accuracy expressed as the % E(r) was found to be between -12.3 and 12.2%. Precision expressed as the % RSD was found to be less than 11.7% for all antidepressants. The developed method proved to be suitable for routine work and it was used to successfully analyze more than 2500 clinical and forensic blood samples.

First systematic evaluation of the potency of Cannabis sativa plants grown in Albania.

Cannabis products (marijuana, hashish, cannabis oil) are the most frequently abused illegal substances worldwide. Delta-9-tetrahydrocannabinol (THC) is the main psychoactive component of Cannabis sativa plant, whereas cannabidiol (CBD) and cannabinol (CBN) are other major but no psychoactive constituents. Many studies have already been carried out on these compounds and chemical research was encouraged due to the legal implications concerning the misuse of marijuana. The aim of this study was to determine THC, CBD and CBN in a significant number of cannabis samples of Albanian origin, where cannabis is the most frequently used drug of abuse, in order to evaluate and classify them according to their cannabinoid composition. A GC-MS method was used, in order to assay cannabinoid content of hemp samples harvested at different maturation degree levels during the summer months and grown in different areas of Albania. This method can also be used for the determination of plant phenotype, the evaluation of psychoactive potency and the control of material quality. The highest cannabinoid concentrations were found in the flowers of cannabis. The THC concentrations in different locations of Albania ranged from 1.07 to 12.13%. The influence of environmental conditions on cannabinoid content is discussed. The cannabinoid content of cannabis plants were used for their profiling, and it was used for their classification, according to their geographical origin. The determined concentrations justify the fact that Albania is an area where cannabis is extensively cultivated for illegal purposes.

Carbon monoxide-related deaths in Greece: a 23-year survey.

Carbon monoxide (CO) is the cause of more than one half of the fatal poisonings throughout the world. The aim of this study was to assess the characteristics of nonfire CO-related deaths in Greece, as they were recorded at the Department of Forensic Medicine and Toxicology, School of Medicine, University of Athens. This retrospective study concerned the toxicological records of all fatal cases of CO poisoning received by the Department of Forensic Medicine and Toxicology during the period 1987 to 2009. The records were reviewed and compiled according to the official coroner's verdict as to the manner of poisoning (accident or suicide), as well as according to the sex and the nationality of the victims. The registered victims were 176 (131 males, 45 females). Of CO deaths, 97.2% were accidental, and 2.8% were suicides, through automobile exhaust. Among the decedents, 32 victims were immigrants (30 males, 2 females). The average annual death rate for males was nearly 3½ times higher than that for females. This increase suggests a need for preventive strategies targeting not only high-risk population, such as homeless or immigrants, but also the general population. Preventive messages in many languages through the media about potential sources of CO exposure are recommended. Precautions should also be taken during periods of low temperatures.

Development and validation of a simple GC-MS method for the simultaneous determination of 11 anticholinesterase pesticides in blood--clinical and forensic toxicology applications.

Anticholinesterase pesticides are widely used, and as a result they are involved in numerous acute and even fatal poisonings. The aim of this study was the development, optimization, and validation of a simple, rapid, specific, and sensitive gas chromatography-mass spectrometry method for the determination of 11 anticholinesterase pesticides (aldicarb, azinphos methyl, carbofuran, chlorpyrifos, dialifos, diazinon, malathion, methamidophos, methidathion, methomyl, and terbufos) in blood. Only 500 µL of blood was used, and the recoveries after liquid-liquid extraction (toluene/chloroform, 4:1, v/v) were more than 65.6%. The calibration curves were linear (R(2) ≥ 0.996). Limit of detections and limit of quantifications were found to be between 1.00-10.0 and 3.00-30.0 µg/L, respectively. Accuracy expressed as the %E(r) was found to be between -11.0 and 7.8%. Precision expressed as the percent relative standard deviation was found to be <9.4%. The developed method can be applied for the investigation of both forensic and clinical cases of accidental or suicidal poisoning with these pesticides.

Accidental poisoning after ingestion of "aphrodisiac" berries: diagnosis by analytical toxicology.

BACKGROUND: A large number of plants, seeds, and berries have been used for medicinal, psychotropic, or aphrodisiac purposes for a thousand years. Mandragora officinarum belongs to the family of Solanaceae and is traditionally known as an aphrodisiac and is closely associated with witchcraft. OBJECTIVES: In this study we report a case of an accidental poisoning after ingestion of some "aphrodisiac" berries and the contribution of the toxicological analysis in the case investigation. CASE REPORT: A 35-year-old man was admitted to the hospital with clinical signs and symptoms of an anticholinergic syndrome. The diagnosis of the poisoning was made by the toxicological analysis of the patient's urine. The cause of the poisoning was revealed by his girlfriend's disclosure that the patient had intentionally consumed some "aphrodisiac" berries to enhance his sexual performance. Subsequently, berries similar to the ones consumed were sent to the laboratory. The analysis of the urine and the berries revealed the presence of hyoscyamine and scopolamine; the berries were identified as Mandragora officinarum berries. Decontamination and symptomatic treatment were proven effective for the control of this poisoning. The patient recovered completely after hospitalization for 4 days. CONCLUSION: This case report indicates the importance of analytical toxicology in diagnosis of intoxications after the consumption of unknown plants or plant products and presents the clinical aspects of Mandragora intoxication.

A simple and sensitive GC/MS method for the determination of atropine during therapy of anticholinesterase poisoning in serum samples.

Atropine is used in the daily clinical practice for the treatment of poisonings caused by anticholinesterase pesticides, due to its sympathomimetic action. The investigation of the cause of the adverse effects that appear during atropine administration showed the necessity for the development and validation of a simple, rapid, sensitive, and specific method for the determination of atropine levels in serum samples. The developed method includes liquid-liquid extraction with ethyl acetate: dichloromethane (3:1, v/v) and derivatization using N,O-bis(trimethylsilyl)-trifluoracetamide (BSTFA) with 1% trimethylchlorsilane (TMCS) in acetonitrile environment. The method was found to be selective, linear, accurate, and precise according to international guidelines. The recovery was higher than 85.9%, the limit of quantification was 2.00 ng/ml, and the calibration curve was linear within the range of 2.00-500 ng/ml (R(2) ≥ 0.992). Accuracy and precision were also calculated and were found to be less than 5.2 and 8.7%, respectively. The developed method was applied in a real case of accidental poisoning with chlorpyrifos in order to determine the atropine serum levels of the patient. The proposed method proved to be useful for the investigation of adverse effects that appear during atropine treatment of patients poisoned by anticholinesterase pesticides and it can also be used for the investigation of poisonings caused after consumption of atropine containing plants.

Development and validation of a method for the determination of buprenorphine and norbuprenorphine in breast milk by gas chromatography-mass spectrometry.

Buprenorphine (BUP) is used for the maintenance of opioid-addicted pregnant women. Because BUP and its main metabolite nor-BUP are excreted into breast milk, a sensitive and specific GC/MS method has been developed, optimized and validated for their determination in breast milk. BUP-d4 was used as internal standard. The sample preparation includes combination of protein precipitation with solid-phase extraction and derivatization (acetylation). The absolute recovery for both analytes was found to be higher than 87.3%. The limits of detection and quantification were 0.07 and 0.20 µg/L, respectively. The calibration curves were linear within the dynamic range 0.20-20.0 µg/L, with a correlation coefficient higher than 0.996. Intra- and inter-day accuracies were ranged from -7.06 to 4.50 and from -5.88 to 7.00%, respectively, while intra- and inter-day precision were less than 5.7 and 6.1%. The analytes were found to be stable in breast milk at 4 °C for one week, at -20 °C for one month, and after three freeze-thaw cycles. The method can be used for the determination of BUP and nor-BUP in breast milk of BUP-maintained mothers, in order to calculate the amount of drug that could pass to the newborn via breast milk and to avoid toxic consequences of breastfeeding.

Development and validation of a gas chromatography-mass spectrometric method for the determination of sildenafil and desmethyl-sildenafil in whole blood.

Sildenafil (SDL) is a phosphodiesterase type 5 inhibitor and it is approved for the treatment of erectile dysfunction and pulmonary hypertension. SDL is extensively metabolized to its pharmacologically active metabolite, desmethyl-sildenafil (DSDL). A sensitive and specific GC/MS method for the determination of SDL and DSDL in whole blood was developed and validated to support therapeutic drug monitoring of SDL patients. The combination of solid-phase extraction with derivatization using BSTFA with 1% TMCS in acetonitrile efficiently reduced matrix effect and improved sensitivity of the method. In this assay, protriptyline was used as internal standard for both analytes. The LODs were 1.50 and 5.00 ng/mL for SDL and DSDL, respectively, whereas the respective LOQs were 5.00 and 15.0 ng/mL. The calibration curves were linear up to 500.0 ng/mL (SDL: R(2) 0.992, DSDL: R(2) 0.990). Absolute recovery values for both analytes ranged from 83.1 to 93.2%. Within- and between-batch accuracy was less than 11.8 and 10.2%, respectively, whereas within- and between-batch precision was less than 8.1 and 10.8%, correspondingly. The developed method is suitable for the determination of SDL and DSDL concentrations in blood samples obtained from patients under Viagra(®) treatment, for pharmacokinetic studies or for the investigation of related forensic cases.

Serum selenium levels do not differ in type 2 diabetic subjects with and without coronary artery disease.

BACKGROUND: The aim of the present study was to investigate whether selenium levels differ between type 2 diabetic subjects with and without coronary artery disease (CAD). METHODS: A total of 200 subjects with type 2 diabetes (100 with CAD and 100 without CAD), consecutively selected from the diabetes outpatient clinic of our hospital were enrolled into the study. A detailed medical history and a physical examination were obtained by all the participants. RESULTS: Serum selenium levels did not differ between diabetic subjects with and without CAD (102.40 ± 31.10 vs. 108.86 ± 33.88 microg/L, p = 0.16). In diabetic subjects with CAD multivariate linear regression analysis demonstrated significant independent associations between selenium and sex (beta = 0.21, p = 0.03) and glucose levels (beta = 0.25, p = 0.008). In diabetic subjects without CAD multivariate linear regression analysis demonstrated significant independent associations between selenium and peripheral artery disease (beta = 0.16, p = 0.05) and glucose levels (beta = -0.09, p = 0.05). CONCLUSION: Serum selenium levels did not differ between diabetic subjects with and without CAD. In diabetic subjects with CAD, the only determinants of serum selenium levels were sex and glucose levels. In diabetic subjects without CAD the only determinants of serum selenium levels were peripheral artery disease and glucose levels.

Development and validation of an EI-GC/MS method for the determination of sertraline and its major metabolite desmethyl-sertraline in blood.

A sensitive and specific GC/MS method for the determination of sertraline and its main metabolite desmethyl-sertraline in whole blood has been developed, optimized and validated. Sample preparation included solid-phase extraction of both analytes and their derivatization with heptafluorobutyric anhydride (HFBA). Protriptyline was used as internal standard for the determination of both analytes. Limits of detection and quantification for both sertraline and desmethyl-sertraline were 0.30 and 1.00 µg/L, respectively. The calibration curves were linear within the dynamic range of each analyte (1.00-500.0 µg/L) with a correlation coefficient (R(2)) exceeding 0.991. Extraction efficiency ranged from 90.1(± 5.8)% to 95.4(± 3.0)% for sertraline, and from 84.9(± 8.2)% to 107.7(± 4.4)% for desmethyl-sertraline. The precision for sertraline and desmethyl-sertraline was between 3.6-5.5% and 4.7-7.2%, respectively, while the accuracy was in the range of -6.67% to 2.20% and -6.33% to 2.88% for sertraline and desmethyl-sertraline, respectively. The method was applied to real blood samples obtained from patients that follow sertraline treatment and also in cases of forensic interest. The developed method can be used in routine every day analysis by clinical and forensic laboratories, for pharmacokinetic studies, for therapeutic sertraline monitoring or for the investigation of forensic cases where sertraline is involved.

Development and validation of a GC/MS method for the determination of tadalafil in whole blood.

Tadalafil is a phosphodiesterase type 5 (PDE-5) inhibitor and it is used in the treatment of pulmonary arterial hypertension and erectile dysfunction. A sensitive and specific method is described for the determination of tadalafil in whole blood. Tadalafil and its internal standard (protriptyline) were isolated from the matrix by solid phase extraction, and were analyzed by gas chromatography/mass spectrometry (GC/MS) after derivatization by N,O-bis(trimethylsilyl)-trifluoracetamide (BSTFA) with 1% trimethylchlorsilane (TMCS). Limits of detection and quantification for tadalafil were 0.70 and 2.00 µg/L, respectively. The calibration curve was linear between 2.00 and 500.0 µg/L, with a correlation coefficient higher than 0.991. The values obtained for intra- and inter-day accuracy was found to be between -10.5 to 8.5% and -4.2 to 4.5%, respectively, while intra- and inter-day precision were less than 8.4 and 11.2%, correspondingly. Absolute recovery was determined at three concentration levels and ranged from 92.1 to 98.9%. The proposed method is the first fully validated GC/MS method for the determination of tadalafil in whole blood and it can be routinely applied by toxicological laboratories, for pharmacokinetic studies, for therapeutic drug level monitoring or for the investigation of related forensic cases.