A fatal case of desvenlafaxine and paroxetine poisoning.

Desvenlafaxine (O-desmethylvenlafaxine) and paroxetine are antidepressants that inhibit serotonin reuptake. Despite their relatively safe profiles, several serious side effects, including serotonin syndrome, bleeding, mania, and high blood pressure, are observed. We report the confirmation of the death of a 41-year-old female, with an overdose of desvenlafaxine and paroxetine suspected as the main cause of death. To quantify the level of desvenlafaxine and paroxetine in whole blood and urine, solid phase extraction combined with liquid chromatography-tandem mass spectrometry was developed and validated. Calibration curves were linear with coefficients of determination (r2) >0.999 for desvenlafaxine and paroxetine. The limits of detection and the limits of quantification for both desvenlafaxine and paroxetine were 0.001 µg/mL and 0.02 µg/mL, respectively. Desvenlafaxine and paroxetine were detected in the postmortem samples, along with various psychiatric drugs, and the blood alcohol content level was below 0.010%. The concentrations of desvenlafaxine and paroxetine in the heart blood were 11.0 µg/mL and 2.1 µg/mL, respectively, indicating lethal concentrations. In the urine, the concentrations of desvenlafaxine and paroxetine were 87.7 µg/mL and 3.5 µg/mL, respectively. This is the first report to determine the blood concentration of desvenlafaxine in a fatal intoxication caused by an overdose of desvenlafaxine single formulation.

Forensic investigation on a combined death by food aspiration and acute escitalopram intoxication occurred to a psychiatric subject in a nursing home.

Food aspiration is one of the major health risks for elderly people in nursing homes which could lead to death. Moreover, misconducts in pharmacotherapy may represent a potential risk of adverse drug reactions. It is reported here the toxicological evaluation of a combined death by food aspiration and acute escitalopram intoxication of a psychiatric subject, occurred in a nursing home. An 89-year-old man, suffering from dysphagia and Alzheimer's, was resident in a nursing home. He was fed with a liquid diet administered directly in mouth using a syringe. The man was also being treated with escitalopram 10 mg tablet. One evening, after receiving the meal in the usual way, the man complained of sudden illness. Carried to the emergency room, the man died about 3 h later with a diagnosis of cardiogenic shock subsequentially to ab ingestis. The histological findings revealed the presence of exogenous material, probably food, up to the finest bronchial branches. The toxicological examination revealed the presence of escitalopram and its main metabolite, desmethylcitalopram: in the blood 1972 ng/ml and 285 ng/ml, in the brain 4657 ng/g and 1025 ng/g, in the gastric content 2317 ng/g and 423 ng/g, in the lung 21,771 ng/g and 468 ng/g, respectively. The bad practice of the nurses to dissolve the escitalopram tablet in the liquefied food and to administer the therapy with a syringe directly into the mouth emerged thanks this investigation. Following food aspiration, escitalopram was absorbed by inhalation route, reaching high concentrations in blood and tissues. The death occurred due to a combined mechanism between food aspiration and the escitalopram toxic action.

Concentrations of citalopram and escitalopram in postmortem hair segments.

Hair analysis can provide information regarding previous drug intake and use patterns, as the drugs consumed are incorporated into the hair. Therefore, reference values for drugs in hair are valuable in forensic investigations, especially when evaluating drug intake and assessing drug tolerance. The aim of the study was to determine concentrations of citalopram, escitalopram, and their primary metabolites in hair segments from deceased individuals with mental illness. Concentrations in up to six months prior to death were evaluated and compared with the estimated daily doses. Hair samples collected from 47 deceased individuals, were segmented in one to six 1 cm segments, and extracted overnight in medium. The concentrations in hair were quantified via ultra-high-performance liquid chromatography-tandem mass spectrometry. Following this quantification, the extracts were reanalyzed qualitatively using a chiral method to distinguish between citalopram and escitalopram intake. We found hair concentrations (10-90 percentile (perc.)) of citalopram from 0.12 to 67 ng/mg with a median of 8.2 ng/mg (N = 40 individuals, n = 182 segments) and of escitalopram from 0.027 to 7.0 ng/mg with a median of 3.9 ng/mg (N = 4, n = 23). The metabolite-to-drug ratios in hair (10-90 perc.) of citalopram were 0.091-0.57 with a median of 0.30 (N = 39) and of escitalopram were 0.053-0.63 with a median of 0.41 (N = 3). No correlations were found between concentrations in the hair and the estimated daily dose. However, our results indicate higher concentrations in dark hair compared to light hair, given the estimated doses, and thus an influence of hair color on the results. A significant positive correlation was found between the concentration of citalopram in the proximal segment and the blood concentrations. The median R/S-ratio of citalopram in hair was 1.5 and was similar to previously reported ratios in blood. In the present study, we report concentrations of citalopram and escitalopram in postmortem hair and their relation to an estimated daily dose and thus contribute valuable information in forensic investigations.

Consumption and ocurrence of antidepressants (SSRIs) in pre- and post-COVID-19 pandemic, their environmental impact and innovative removal methods: A review.

Selective serotonin reuptake inhibitors (SSRIs) are pharmaceuticals whose consumption has increased significantly. They are prescribed as first-line treatment in mental disorders such as depression, obsessive-compulsive disorder, phobias, and anxiety; also, they are indicated as adjuvants in diseases such as fibromyalgia and bulimia nervosa. In addition to being linked to the illegal market to be consumed as recreational drugs. The relevance of this review lies in the fact that worldwide consumption has increased significantly during the COVID-19 pandemic, due to the depression and anxiety that originated in the population. As a consequence of this increase in consumption, concentrations of SSRIs in the environment have increased, and these have become a relevant issue for toxicologists due to the effects that they could generate in different organisms, both aquatic and terrestrial. For this reason, the objective of this article was to do a critical evaluation of the existing data on the characteristics and physicochemical properties of SSRIs, consumption data during the COVID-19 pandemic, its occurrence in the environment and the reports of toxic effects that have been generated in different organisms; we also conclude with an updated review of different methods that have been used for their removal. With this analysis, it can be concluded that, despite SSRIs are pharmaceutical products widely studied since their launching to the market, still currently under investigation to clarify their mechanisms of action to understand the different effects on the organisms, adverse reactions, as well as possible toxicological effects on non-target organisms. On the other hand, it has been proven that although it is already possible to eliminate a significant percentage of SSRIs in the laboratory, due to their physicochemical characteristics and their behavior in complex mixtures in the environment, they have not yet been eradicated, showing a persistence in the soil, subsoil and surface waters of the entire planet that may represent a future risk.

Determination of citalopram in fish brain tissue: benefits of coupling laser diode thermal desorption with low- and high-resolution mass spectrometry.

Recent state-of-the-art methods developed for the analysis of polar xenobiotics from different types of biological matrices usually employ liquid chromatography with mass spectrometry. However, there are limitations when a small amount of sample mass is available. For example, individual benthic invertebrates or fish tissue samples often weigh less than 100 mg (e.g., brain, liver) but are necessary to understand environmental fate and bioaccumulation dynamics. We developed ultra-fast methods based on a direct sample introduction technique. This included coupling laser diode thermal desorption with atmospheric pressure chemical ionization mass spectrometry (LDTD-APCI-MS). We then quantitated a common selective serotonin reuptake inhibitor (citalopram) in brain tissues of individual juvenile fish after in vivo exposure to environmentally relevant concentration. Two mass spectrometric methods based on low (LDTD-APCI-triple quadrupole (QqQ)-MS/MS) and high (LDTD-APCI-high-resolution product scan (HRPS)) resolutions were developed and evaluated. Individual instrument conditions were optimized to achieve an accurate and robust analytical method with minimum sample preparation requirements. We achieved very good recovery (97-108%) across the range of 1-100 ng g-1 for LDTD-APCI-HRPS. LDTD-APCI-QqQ-MS/MS showed poorer performance due to interferences from the matrix at the lowest concentration level. LDTD-APCI ionization was successfully validated for analysis of non-filtered sample extracts. Evaluation of final methods was performed for a set of real fish brain samples, including comparison of LDTD-APCI-HRPS with a previously validated LC-heated electrospray ionization-HRPS method. This new LDTD-APCI-HRPS method avoids the chromatographic step and provides important benefits such as analysis of limited sample masses, lower total sample volume (typically µL), and reduction in analysis time per sample run to a few seconds. Graphical abstract.

Ultrasound-assisted dispersive liquid-liquid microextraction coupled with field-amplified capillary electrophoresis for sensitive and quantitative determination of fluoxetine and norfluoxetine enantiomers in biological fluids.

A rapid, simple, and sensitive technique for the quantitative detection of fluoxetine and norfluoxetine enantiomers in biological fluids was developed based on the combination of field-amplified sample stacking (FASS)-related capillary electrophoresis (CE) with ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME). The extraction efficiency of UA-DLLME was strongly related to extraction time, salt concentration, type of extraction and dispersion solvents, and volume of extraction and dispersion solvents. The extracted fluoxetine and norfluoxetine enantiomers in a mixture of 50% methanol and 50% deionized water were efficiently stacked using FASS and then separated using cyclodextrin-modified CE. Under optimal conditions of FASS (chiral selector, 3 mM trimethyl-ß-cyclodextrin; and background electrolyte, 100 mM phosphate buffer) and UA-DLLME (extraction solvent, 200 µL of acetone; and dispersed solvent, 50 µL of C2H2Cl4 in 1 mL of the sample solution), the obtained enrichment factors of fluoxetine and norfluoxetine enantiomers reached approximately 2000. The linear ranges for the quantification of fluoxetine and norfluoxetine enantiomers were 0.3-150 and 0.6-150 nM, respectively. The relative standard deviations in peak areas and migration time for four analytes were less than 3.3% and 6.3%, respectively. The proposed system provided limits of detection (signal-to-noise ratio of 3) for four analytes corresponding to 0.1 nM. The precision and accuracy for urine and serum samples were less than 6.8 and 8.3%, respectively. These findings suggested that the proposed system exhibited a high potential for the reliable determination of fluoxetine and norfluoxetine enantiomers in clinical samples. Graphical abstract.

Ultraviolet cutoff area and predictive ability of partial least squares regression method: A pharmaceutical case study.

UV cutoff area (COA) is known to be the wavelength band where solvents used for analysis can absorb radiation and accordingly affect the absorption spectra of drugs of interest being analyzed, even if blank experiments are done to eliminate solvent interference. However, this area may show peaks of significance for some drugs, and accordingly some researchers tend to include it in analysis. This study is presenting the importance of avoiding using COA, where it may represent significant negative effect on predictive ability of some linear chemometric methods like partial least squares regression PLSR. The presented study is using previously analyzed pharmaceutical mixtures of Dapoxetine Hydrochloride (DAP) and Tadalafil (TAD) as a case study, whether in pure forms or in dosage form, where the study uses two datasets for analysis, the first aims to include COA and the second dataset avoids it, then a statistical comparison is conducted for training sets, test sets and dosage form datasets to see how far COA may interfere with analysis results. Generally, the results show significant difference in datasets for t and F statistics for analysis of dosage form sets; which reflects changes in predictive ability of used chemometric method upon inclusion of COA in absorbance datasets, and accordingly unsuitability of using COA especially for routine quality control analysis of pharmaceutical mixtures.

Enantioselective LC analysis and determination of selective serotonin reuptake inhibitors.

LC separation of biologically and pharmaceutically important enantiomers (from racemic or non-racemic mixtures) remains a subject of importance. The present review article deals with the liquid chromatographic enantioseparation of chiral selective serotonin reuptake inhibitors (SSRIs), namely citalopram, paroxetine, sertraline and fluoxetine. It is now known that the enantiomers of numerous psychotropic drugs exhibit distinct pharmacodynamics, pharmacokinetic patterns and receptor binding properties, and psychiatric patients are frequently taking more than one medication. Therefore, monitoring of the levels of these analytes in biological fluids is important to determine the levels of enantiomer concentrations; the present paper may be helpful in understanding the present state of available methods (along with a critical discussion of applicability of the methods) and in developing the new ones for this purpose. Different approaches using LC discussed herein may be applied for determining the enantiomeric composition (and enantiomeric purity) of SSRIs and numerous other racemic drugs, of current/future pharmaceutical importance and utility, using simple separation methods, instrumentation, inexpensive reagents and potentially significant analytical approaches. The contents cover the essential data to understand the various separation techniques and associated issues, if any, with documented examples.

Analytical methodologies for the enantiodetermination of citalopram and its metabolites.

Citalopram (CIT) is a highly selective serotonin reuptake inhibitor (SSRI) frequently used in the treatment of major depressive disorders. It has a chiral centre in its structure and is used in therapy both as a racemic mixture (R,S-CIT) and a pure enantiomer (S-CIT). The differences between the pharmacokinetic and pharmacological profiles of the two enantiomers are well established. Consequently, the development of new efficient chiral analysis methods for their enantiomeric separation is a topic of great actuality. CIT metabolism is stereoselective as it is metabolized in chiral active metabolites, which retain considerable SSRI activity and contribute to the pharmacological effect. Chiral analytical methods are employed for the determination of enantiomeric ratio in pharmaceutical preparations and for monitoring the enantiomer levels in biological samples for therapeutic and toxicologic purposes. The current study reviews the published literature for the chiral analysis of CIT and its metabolites based on chromatographic and electrophoretic methods coupled with UV, fluorescence and mass spectrometry detectors.

High resolution mass spectrometry analysis of the sertraline residues contained in the tissues of rainbow trout reared in model experimental conditions.

The growing consumption of pharmaceuticals in the human population and the insufficient efficiency of their elimination in waste water has a long-term negative impact on the environment of aquatic ecosystems, including the organisms that inhabit them. A significant contributor is the consumption of anti-depressants from the SSRI group, which corresponds to their increasing concentration in the environment. The aim of this work was to determine if antidepressant sertraline is able to be stored in fish organisms and to evaluate the content of residues in various body tissues. Rainbow trout (Oncorhynchuss mykkis) was selected as the test organism and was artificially exposed to the antidepressant for 1 month (concentrations 0; 4.2; 44 and 400 ng.g-1 sertraline in the feed). Liver, kidney, brain and muscle tissue biopsies samples were taken for analysis. Detection was performed using an Accela 1250 LC pump and an Accela autosampler coupled with a high-performance mass analyzer with a heated electrospray ionization source Q-Exactive Orbitrap, operating in positive ionization mode and in PRM mode (m/z 306.08108->275.03888 and 309.009991->275.03888 for sertraline and internal standard, respectively). The limit of quantification of the method was 0.1 ng.g-1 of sertraline and the calibration curve showed a good linearity up to 20 ng.g-1. From the collected data, amount of residues was found in the liver, kidney and brain. In contrast, the incidence of residues in muscle tissue was not detected in all groups, which is favorable from the point of view of fish meat consumption, by humans.

Postmortem analysis of human bone marrow aspirate - Quantitative determination of SSRI and SNRI drugs.

For the first time the MAE/UHPLC-TOFMS method was developed and used in order to determine the antidepressant drugs within the human bone marrow aspirate in real forensic cases. The following drugs, belonging to the group of selective serotonin (or serotonin-norepinephrine) reuptake inhibitors, were tested in this study: venlafaxine, citalopram, fluoxetine, sertraline and paroxetine. The sample preparation proposed in the present article included several steps: homogenization in ultrasound bath, liquid-liquid extraction, fat removal and evaporation under nitrogen. The extraction involved microwave-assisted extraction, performed for 15 min at 55 °C, with hexane-isoamyl alcohol (99:1, v/v) mixture, as an extraction solvent. Time and temperature of extraction were optimized using the simplex method. The fat removal step was introduced because of the fatty nature of the bone marrow that resulted in insufficiently purified samples, impossible to analyze using HPLC. It was achieved by adding a mixture of ethanol, water and formic acid to samples consisting of hexane and isoamyl alcohol, so that the analytes could diffuse to polar phase and fat could stay in non-polar phase. The method was validated and parameters such as: LOD, LOQ, linearity, matrix effect, recovery were determined. The validation parameters obtained allowed to recognize the method as quantitative. Due to lack of the data on therapeutic and toxic levels of considered drugs in bone marrow, data regarding serum has been used for reference. Under this assumption, the developed method allows for quantification of all mentioned drugs at therapeutic levels. Moreover this method has been used in real cases. Finally four analytes: venlafaxine (104 ng/mL), fluoxetine (84 ng/mL), paroxetine (about 3.6 µg/mL) and citalopram (68 ng/mL) were found in three case samples.

Space-Resolved Tissue Analysis by Solid-Phase Microextraction Coupled to High-Resolution Mass Spectrometry via Desorption Electrospray Ionization.

It is hard to overstate the tremendous utility of desorption electrospray ionization (DESI) and its various configurations for rapid and high-throughput analyses or spatially resolved imaging of heterogeneous systems. However, there have been few attempts to employ this technique in spatially resolved mode with solid substrates featuring extractive and analyte-enrichment properties. This study documents the development of a platform that combines solid-phase microextraction (SPME) with desorption electrospray ionization mass spectrometry (DESI-MS) for unidimensional investigation of the heterogeneous distribution of compounds in semisolid systems (i.e., depth profiling across the fiber axis), with the ultimate end of employing it for brain tissue analysis. To this end, a DESI interface and a custom holder accommodating SPME probes were built in house, with the latter contributing to reduction of mechanical sources of signal instability. The system was evaluated through the quantitative reconstruction of the laminar and radial concentration gradients of xenobiotics introduced in multilayer gel arrangements and surrogate brain tissue models. Good quantitative capability was achieved by employing a strategy that combined signal correction via preloading internal standard onto SPME fibers and signal integration in scan-by-scan mode. The proposed technique's suitability for characterizing more complex systems, such as rat brains ex vivo, was also evaluated. The proposed approach allows for fast and noninvasive probing of three-dimensional objects without the need for their slicing, and the space-resolved mode reduces the number of required probe insertions, allowing in vivo applications. We foresee suitability of this setup for examining the spatial patterns of local drug release in the brain and the extent of the resultant physiological responses.

Global scanning of selective serotonin reuptake inhibitors: occurrence, wastewater treatment and hazards in aquatic systems.

As the global population becomes more concentrated in urban areas, resource consumption, including access to pharmaceuticals, is increasing and chemical use is also increasingly concentrated. Unfortunately, implementation of waste management systems and wastewater treatment infrastructure is not yet meeting these global megatrends. Herein, pharmaceuticals are indicators of an urbanizing water cycle; antidepressants are among the most commonly studied classes of these contaminants of emerging concern. In the present study, we performed a unique global hazard assessment of selective serotonin reuptake inhibitors (SSRIs) in water matrices across geographic regions and for common wastewater treatment technologies. SSRIs in the environment have primarily been reported from Europe (50%) followed by North America (38%) and Asia-Pacific (10%). Minimal to no monitoring data exists for many developing regions of the world, including Africa and South America. From probabilistic environmental exposure distributions, 5th and 95th percentiles for all SSRIs across all geographic regions were 2.31 and 3022.1 ng/L for influent, 5.3 and 841.6 ng/L for effluent, 0.8 and 127.7 ng/L for freshwater, and 0.5 and 22.3 ng/L for coastal and marine systems, respectively. To estimate the potential hazards of SSRIs in the aquatic environment, percent exceedances of therapeutic hazard values of specific SSRIs, without recommended safety factors, were identified within and among geographic regions. For influent sewage and wastewater effluents, sertraline exceedances were observed 49% and 29% of the time, respectively, demonstrating the need to better understand emerging water quality hazards of SSRIs in urban freshwater and coastal ecosystems. This unique global review and analysis identified regions where more monitoring is necessary, and compounds requiring toxicological attention, particularly with increasing aquatic reports of behavioral perturbations elicited by SSRIs.

A fluvoxamine-related fatality: Case report with postmortem concentrations.

Fluvoxamine is a selective serotonin reuptake inhibitor that has been considered relatively safe in overdose. At therapeutic and supratherapeutic concentrations, fluvoxamine affects cardiac conduction, prolongs QTc interval, causes hypotension, obtundation, and can increase propensity for seizures. A man in his 60s was found dead at his home with a postmortem fluvoxamine peripheral blood concentration of 4.9 mg/L, and a liver concentration of 440 mg/kg. His cause of death was determined to be acute fluvoxamine toxicity.

Segmental Hair Analysis-Interpretation of the Time of Drug Intake in Two Patients Undergoing Drug Treatment.

The present study involved segmental testing of hair in two clinical cases with known dosage histories. Hair analysis confirmed the first patient's exposure to the prescribed sertraline and citalopram for several months. Citalopram was generally distributed along the hair shaft in accordance with the drug ingestion period. By contrast, "false" positive results were observed for sertraline in distal hair segments, corresponding to a period of no sertraline exposure, which may indicate incorporation from sweat or sebum, which transport the drugs along the hair surface. The second patient received various drugs during her treatment for brain cancer. Metoclopramide, morphine, oxazepam, paracetamol, sumatriptan, tramadol, and zopiclone, which had been part of the therapy, were all detected in the proximal hair segment. The results of these two cases indicated that results-especially concerning the time of drug intake-must be interpreted with caution and allow for the possibility of incorporation from sweat or sebum.

Capillary electrophoresis method for the determination of (R)-dapoxetine, (3S)-3-(dimethylamino)-3-phenyl-1-propanol, (S)-3-amino-3-phenyl-1-propanol and 1-naphthol as impurities of dapoxetine hydrochloride.

A capillary electrophoresis method was developed and validated for the determination of the purity of dapoxetine with regard to the related substances (3S)-3-amino-3-phenylpropan-1-ol, (3S)-3-(dimethylamino)-3-phenylpropan-1-ol, 1-naphthol and the enantiomer (R)-dapoxetine. The separation was based on a dual selector system, which was optimized by a fractional factorial resolution V + design followed by a central composite face centered design with star distance 1 and Monte Carlo simulations for defining the design space. The optimized background electrolyte consisted of a 50 mM sodium phosphate buffer, pH 6.3, containing 45 mg/mL sulfated γ-cyclodextrin and 40.2 mg/mL 2,6-dimethyl-ß-cyclodextrin. Separations were carried out in a 23.5/32 cm, 50 µm fused-silica capillary employing a separation voltage of 9 kV at 15 °C. Following robustness testing using a Plackett-Burman design the method was validated according to the International Council on Harmonization guideline Q2(R1) in the range of 0.05-1.0% relative to the dapoxetine concentration. The method was applied to the analysis of drug substance and a commercial tablet. Data regarding the enantiomeric purity of dapoxetine obtained by the capillary electrophoresis assay were comparable to the data obtained by an enantioselective HPLC method.

Antidepressants in breast milk; comparative analysis of excretion ratios.

Despite increasing prescription rates of antidepressants in pregnant and breastfeeding women over the past decades, evidence of drug exposure for neonates through lactation is very sparse. Concentrations of three antidepressants citalopram, sertraline, and venlafaxine were measured in maternal blood and breast milk in 17 women receiving antidepressant therapy during breastfeeding period. We also computed concentration-by-dose-ratios (C/D) and milk to serum (plasma) penetration ratios (M/P). Non-parametric tests were applied. Serum concentration of citalopram and daily dosage correlated positively while daily dosage and mother milk concentration did not (rho = 0.939, p = 0.005, and rho = 0.772, p > 0.05 respectively). A significant correlation was also found between serum and milk concentrations (rho = 0.812, p = 0.05). Venlafaxine daily dosage correlated positively with the active moiety milk concentration (rho = 0.949, p = 0.014). No significant correlations were reported for sertraline. The amount of antidepressant concentrations to which neonates may be exposed, assessed as absolute infant dose (AID), was particularly low with the highest median AID being 0.16 mg/kg/day for venlafaxine. No significant difference was detected for the M/P ratios between different drugs (p > 0.05), whereas the comparison of C/D ratios revealed lower values in the sertraline group, with the highest values reported for citalopram group (p = 0.007 for serum concentrations and p = 0.008 for mother milk). Findings suggest that breastfeeding under antidepressant treatment constantly exposes children with measurable drug concentrations. As daily dosage and serum concentration of the antidepressants did not predict drug concentrations in mother milk, measuring of drug concentrations in milk helps to quantify drug exposure during breastfeeding. More data-even data of drug concentrations in breastfed children-are needed to better assess the effects of drug exposure on children's development.

Development of a fluvoxamine detection system using a Quenchbody, a novel fluorescent biosensor.

The misuse of psychotropic drugs intended for medical treatment represents a recent worldwide public health concern. Quenchbody (Q-body) is a novel fluoroimmunosensor that can detect an antigen immediately without additional reagents or washing steps. Here, we describe creating Q-bodies for the detection of the antidepressant fluvoxamine (FLV) and determining optimal conditions to achieve the highest fluorescence intensity (FI). We prepared five Q-bodies with the fluorophore labeled at either the N- or C- terminus and with different linker lengths. Fluorescence was measurable within minutes, indicating the interaction of Q-bodies with FLV. The normalized FI (FI ratio) of the N-terminus labeled Q-body increased approximately 1.5-fold upon FLV addition; Q-bodies labeled at the C-terminus did not significantly increase FI. Among the fluorescence dyes used in this study, Rhodamine 6G labeled Q-body showed the best FI ratio. EC50 values of the N-terminus labeled Q-bodies were similar (23.2-224nM) regardless of linker length or labeling dye. We examined whether the Q-body could be applicable to serum matrix instead of phosphate-buffered saline. The intact serum interfered strongly with the Q-body fluorescence. However, the FI ratios of the Q-body for FLV-spiked serum filtrate, for which proteins were removed by filtration, showed a dose-dependency for detecting FLV levels. Deproteinization, which does not interfere with Q-body fluorescence measurements, is likely necessary to detect serum FLV with high sensitivity. This study demonstrates the potential of Q-body probes as a tool towards developing creative immunoassay applications.

Fatal intoxication with antidepressants: a case with many culprits.

Serotonin-specific reuptake inhibitors (SSRIs) are generally considered safe drugs but fatal adverse effects do sometimes occur, often as a consequence of interactions with other serotonin active drugs. Polypharmacy is usually a problem that the elderly encounter, but it can also have dire consequences for young people, especially when an underlying heart condition is present. Thus, failure to diagnose heart disease and the use of contraindicated medications can be a lethal combination, irrespective of age. Here we present a case of a young adult suffering from bipolar disorder who used a combination of two SSRIs (citalopram and fluoxetine) and a monoamine oxidase inhibitor (MAO; moclobemide) with tragic consequences. The deceased also suffered from undiagnosed hypertrophic cardiomyopathy and was carrier of a genotype that may have predisposed him to increased sensitivity to SSRIs. The apparent difficulty in establishing the manner of death in this case is also discussed.

Analytical methodologies for the stereoselective determination of fluoxetine: An overview.

Fluoxetine is a widely used antidepressant belonging to the selective serotonin reuptake inhibitor class; it is used in the treatment of major depression, obsessive compulsive, premenstrual dysphoric, panic and post-traumatic stress disorders. Fluoxetine is an optical active pharmaceutical substance, which is used as a racemate in therapy, but stereospecific interactions associated with the serotonin-reuptake carrier, for both the parent drug and its active metabolite, norfluoxetine, have been described in the literature. Therefore, the stereoselective analysis of fluoxetine and norfluoxetine is important in order to characterize the pharmacokinetic and pharmacodynamic profile of the analytes. Several chromatographic and electrophoretic methods have been published in the literature for the chiral discrimination of fluoxetine enantiomers from different matrices. The purpose of the current review is to provide a systematic survey of the analytical techniques used for the chiral determination of fluoxetine and norfluoxetine covering a period of ~25 years.