Development and performance of an analytical method for polychlorinated naphthalenes and other persistent organic pollutants in dried blood spots.

BACKGROUND: Dried blood spots (DBSs) collected and archived in newborn screening programs (NSP) represent a potentially valuable resource for assessing exposure to a range of organic and inorganic chemicals in newborns. This study develops and optimizes a method to measure polychlorinated naphthalenes (PCNs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (OCPs) in DBS using the isotope dilution technique, ultrasonic-assisted liquid-liquid extraction, simple cleanup, triple quadrupole GC-MS/MS analysis, and background correction. RESULTS: We minimize the number of extraction repetitions and the volume of solvent, which helps increase throughput while minimizing the potential for contamination. We obtained high recovery and precision for most compounds, and method detection limits (MDLs) were sufficiently low to detect the more prevalent compounds based on representative sample of the US population. MDLs averaged 0.020 ng/mL (recovery: 107 %, precision: 4 %) for PCNs, 0.021 ng/mL (recovery: 97 %, precision: 4 %) for PCBs, 0.021 ng/mL (recovery: 117 %, precision: 2 %) for OCPs, and 0.021 ng/mL (recovery: 96 %, precision: 3 %) for PBDEs. SIGNIFICANCE AND NOVELTY: To our knowledge, this is the first study presenting an analytical method and for PCNs in DBS, and one of the few studies providing an assessment of method performance for persistent organic pollutants in DBS. The optimized method can be applied to a wide range of applications, including exposure assessment, environmental epidemiology, forensics, environmental surveillance, and ecological monitoring.

Profiling population-wide exposure to environmental chemicals: A case study of naphthalene.

Long-term exposure to environmental chemicals can detrimentally impact human health, and understanding the relationship between age distribution and levels of external and internal exposure is crucial. Nonetheless, existing methods for assessing population-wide exposure across age groups are limited. To bridge this research gap, we introduced a modeling approach designed to assess both chronic external and internal exposure to chemicals at the population level. The external and internal exposure assessments were quantified in terms of the average daily dose (ADD) and steady-state blood concentration of the environmental chemical, respectively, which were categorized by age and gender groups. The modeling process was presented within a spreadsheet framework, affording users the capability to execute population-wide exposure analyses across a spectrum of chemicals. Our simulation outcomes underscored a salient trend: younger age groups, particularly infants and children, exhibited markedly higher ADD values and blood concentrations of environmental chemicals compared to their older counterparts. This observation is due to the elevated basal metabolic rate per unit of body weight characteristic of younger individuals, coupled with their diminished biotransformation kinetics of xenobiotics within their livers. These factors collectively contribute to increased intake rates of environmental chemicals per unit of body weight through air and food consumption, along with heightened bioaccumulation of these chemicals within their bodies (e.g., blood). Furthermore, we augmented the precision of the external and internal exposure assessment by incorporating the age distribution across the population. The simulation outcomes unveiled that, to estimate the central tendency of the population's exposure levels, employing the baseline value group (age group 21-30) or the surrogate age of 25 serves as a simple yet dependable approach. However, for comprehensive population protection, our recommendation aligns with conducting exposure assessments for the younger age groups (age group 0-11). Future studies should integrate individual-level exposure assessment, analyze vulnerable population groups, and refine population structures within our developed model.

Polychlorinated naphthalene concentrations and temporal trends in serum from the general Chinese adult population and effects of polychlorinated naphthalenes on thyroid function.

Polychlorinated naphthalenes (PCNs) have stopped being produced and used but have been detected in human serum around the world. Investigating temporal trends in PCN concentrations in human serum will improve our understanding of human exposure to PCNs and the risks posed. We determined the PCN concentrations in serum collected from 32 adults in five consecutive years (2012-2016). The total PCN concentrations in the serum samples were 0.00-5443 pg/g lipid weight. We found no significant decreases in the total PCN concentrations in human serum and even found that the concentrations of some PCN congeners (e.g., CN20) increased over time. We found differences in the PCN concentrations in serum from males and females, the CN75 concentration being significantly higher in serum from females than males, meaning CN75 poses more serious risks to females than males. We found, using molecular docking techniques, that CN75 interferes with thyroid hormone transport in vivo and that CN20 affects thyroid hormone binding to receptors. These two effects are synergistic and can cause hypothyroidism-like symptoms.

Intoxication by a synthetic cannabinoid (JWH-018) causes cognitive and psychomotor impairment in recreational cannabis users.

BACKGROUND: Smoking mixtures containing synthetic cannabinoids (SCs) have become very popular over the last years but pose a serious risk for public health. Limited knowledge is, however, available regarding the acute effects of SCs on cognition and psychomotor performance. Earlier we demonstrated signs of impairment in healthy volunteers after administering one of the first SCs, JWH-018, even though subjective intoxication was low. In the current study, we aimed to investigate the acute effects of JWH-018 on several cognitive and psychomotor tasks in participants who are demonstrating representative levels of acute intoxication. METHODS: 24 healthy cannabis-experienced participants took part in this placebo-controlled, cross-over study. Participants inhaled the vapor of 75 µg JWH-018/kg body weight and were given a booster dose if needed to induce a minimum level of subjective high. They were subsequently monitored for 4 h, during which psychomotor and cognitive performance, vital signs, and subjective experience were measured, and serum concentrations were determined. RESULTS: Maximum subjective high (average 64%) was reached 30 min after administration of JWH-018, while the maximum blood concentration was shown after 5 min (8 ng/mL). JWH-018 impaired motor coordination (CTT), attention (DAT and SST), memory (SMT), it lowered speed-accuracy efficiency (MFFT) and slowed down response speed (DAT). CONCLUSION: In accordance with our previous studies, we demonstrated acute psychomotor and cognitive effects of a relatively low dose of JWH-018.

Equine metabolism of the selective androgen receptor modulator AC-262536 in vitro and in urine, plasma and hair following oral administration.

AC-262536 is one of a number of selective androgen receptor modulators that are being developed by the pharmaceutical industry for treatment of a range of clinical conditions including androgen replacement therapy. Though not available therapeutically, selective androgen receptor modulators are widely available to purchase online as (illegal) supplement products. The growth- and bone-promoting effects, along with fewer associated negative side effects compared with anabolic-androgenic steroids, make these compounds a significant threat with regard to doping control in sport. The aim of this study was to investigate the metabolism of AC-262536 in the horse following in vitro incubation and oral administration to two Thoroughbred horses, in order to identify the most appropriate analytical targets for doping control laboratories. Urine, plasma and hair samples were collected and analysed for parent drug and metabolites. Liquid chromatography-high-resolution mass spectrometry was used for in vitro metabolite identification and in urine and plasma samples. Nine phase I metabolites were identified in vitro; four of these were subsequently detected in urine and three in plasma, alongside the parent compound in both matrices. In both urine and plasma samples, the longest detection window was observed for an epimer of the parent compound, which is suggested as the best target for detection of AC-262536 administration. AC-262536 and metabolites were found to be primarily glucuronide conjugates in both urine and plasma. Liquid chromatography-tandem mass spectrometry analysis of post-administration hair samples indicated incorporation of parent AC-262536 into the hair following oral administration. No metabolites were detected in the hair.

Novel aminoarylcysteine adducts in globin of rats dosed with naphthylamine and nitronaphthalene isomers.

Novel aminonaphthylcysteine (ANC) adducts, formed via naphthylnitrenium ions and/or their metabolic precursors in the biotransformation of naphthylamines (NA) and nitronaphthalenes (NN), were identified and quantified in globin of rats dosed intraperitoneally with 0.16 mmol/kg b.w. of 1-NA, 1-NN, 2-NA and 2-NN. Using HPLC-ESI-MS2 analysis of the globin hydrolysates, S-(1-amino-2-naphthyl)cysteine (1A2NC) together with S-(4-amino-1-naphthyl)cysteine (4A1NC) were found in rats given 1-NA or 1-NN, and S-(2-amino-1-naphthyl)cysteine (2A1NC) in those given 2-NA or 2-NN. The highest level of ANC was produced by the most mutagenic and carcinogenic isomer 2-NA (35.8 ± 5.4 nmol/g globin). The ratio of ANC adduct levels for 1-NA, 1-NN, 2-NA and 2-NN was 1:2:100:3, respectively. Notably, the ratio of 1A2NC:4A1NC in globin of rats dosed with 1-NA and 1-NN differed significantly (2:98 versus 16:84 respectively), indicating differences in mechanism of the adduct formation. Moreover, aminonaphthylmercapturic acids, formed via conjugation of naphthylnitrenium ions and/or their metabolic precursors with glutathione, were identified in the rat urine. Their amounts excreted after dosing rats with 1-NA, 1-NN, 2-NA and 2-NN were in the ratio 1:100:40:2, respectively. For all four compounds tested, haemoglobin binding index for ANC was several-fold higher than that for the sulphinamide adducts, generated via nitrosoarene metabolites. Due to involvement of electrophilic intermediates in their formation, ANC adducts in globin may become toxicologically more relevant biomarkers of cumulative exposure to carcinogenic or non-carcinogenic arylamines and nitroarenes than the currently used sulphinamide adducts.

Imbalances in the disposition of estrogen and naphthalene in breast cancer patients: a potential biomarker of breast cancer risk.

Elevation of naphthoquinones and estrogen quinones, which are reactive metabolites of naphthalene and estrogen, is thought to be an important indicator of naphthalene- and estrogen-induced carcinogenesis. We compared background levels of naphthalene and estrogen quinone-derived adducts in serum albumin (Alb) from 143 women with breast cancer and 119 healthy controls. Cysteinyl adducts of naphthoquinones, including 1,2-naphthoquinone (1,2-NPQ) and 1,4-naphthoquinone (1,4-NPQ), and estrogen quinones, including estrogen-2,3-quinones (E2-2,3-Q) and estrogen-3,4-quinones (E2-3,4-Q), were characterized after adduct cleavage. Levels of estrogen quinones and naphthoquinones were positively correlated in healthy controls, but not in breast cancer patients (p < 0.05). Compared with controls, levels of 1,2-NPQ and E2-3,4-Q were elevated by two- to ten-fold in cancer patients (p < 0.001). To explore the correlation between estrogen- and naphthalene-derived quinone adducts and disease status, we performed linear discriminant analysis of the ratio of 1,2-NPQ-Alb to (1,2-NPQ-Alb plus 1,4-NPQ-Alb) versus the ratio of E2-3,4-Q-2-S-Alb to (E2-2,3-Q-4-S-Alb plus E2-3,4-Q-2-S-Alb) in patients and controls. These two groups were separable using albumin adducts of estrogen quinones and naphthoquinones, with 99.6% overall correct classification rate (overall accuracy). The findings of this study suggest that differences in the disposition of estrogen and naphthalene, and the subsequent elevation of cumulative E2-3,4-Q and 1,2-NPQ may serve as biomarkers of breast cancer risk.

High performance liquid chromatography - Mass spectrometric bioanalytical method for the determination of dapoxetine in human plasma: Application for bioequivalence study.

Dapoxetine is an oral medication used for treatment of premature ejaculation (PE) in men aged (18-64 years). In this study, we present a validated, precise and sensitive method for determination of dapoxetine in human plasma by liquid chromatography/ electrospray ionization-tandem mass spectrometry. Dapoxetine and the internal standard (Dapoxetine- d6) were extracted from plasma via liquid-liquid extraction (LLE). The LC separation was performed utilizing ACE C8 (4.6 X50) mm, 5 µm column. The mobile phase was composed of acetonitrile and buffer (0.01 M Ammonium acetate +0.02% Formic acid solution) (85:15, v/v). The method was linear within the concentration range of 5.0-600 ng/mL for Dapoxetine in human plasma. Short analytical run was achieved with 1.6 min run time. Intra-day and inter-day accuracy was between 97 and 106% with precision (CV, %) of ≤ 5% achieved across all the quality control samples. Dapoxetine was stable in several conditions with recovery rates > 90%. This method was utilized successfully in clinical pharmacokinetic study following oral administration of 60 mg Dapoxetine tablets in 36 healthy male subjects. The result for all 90% confidence intervals were within the preset ranges. The method proved to be highly reproducible and sensitive and thus can be employed in bioequivalence studies and large scale sample analysis of Dapoxetine.

Zein-alpha lipoic acid-loaded nanoparticles to enhance the oral bioavailability of dapoxetine: optimization and clinical pharmacokinetic evaluation.

BACKGROUND: Premature ejaculation (PE) is the most common type of male sexual disorder with important psychological consequences. Dapoxetine (DPX), a recently approved drug for the treatment of PE, suffers from low bioavailability with large variability that ranges from 15-76% (mean 42%) after oral administration. The objective of this study is to optimize the parameters for the preparation of DPX-Zein-alpha lipoic acid (ALA) nanoparticles (NPs) to improve the bioavailability of DPX and consequently decrease therapeutic dose and adverse effect, leading to patient satisfaction and compliance. METHODS: We investigated the effect of ALA concentration, PVA concentration and stirring rate on nanoparticle size (Y1), zeta potential (Y2), initial DPX release (Y3) and cumulative DPX release (Y4). In addition, in vivo pharmacokinetic study was performed for the optimized DPX formulation on human healthy volunteers compared with marketed DPX tablet. RESULTS: The optimized DPX-loaded NPs showed Y1, Y2, Y3, and Y4 of 159.24 nm, 19.14 mV, 25.31% and 95.9 %, respectively. A single oral dose of 30 mg of optimized DPX-loaded NPs to human volunteers resulted in 2-fold improvement of AUC (1376.145±339.592 vs 709.178±146.307 in DPX), 4-fold increase in tmax (2.5±0.314 vs 0.583±0.144), prolongation of MRT (7.637±1.373 compared to 6.031±1.826 h), but with reduction in t1/2 (5.283±1.077 vs 8.452±2.813). CONCLUSION: The clinical findings suggest 194% enhancement of relative bioavailability of the optimized DPX-loaded NPs, potentially leading to a decrease in therapeutic dose and associated side effects in the treatment of PE.

Toxicokinetic Interaction between Hepatic Disposition and Pulmonary Bioactivation of Inhaled Naphthalene Studied Using Cyp2abfgs-Null and CYP2A13/2F1-Humanized Mice with Deficient Hepatic Cytochrome P450 Activity.

Previous studies using Cyp2abfgs-null (lacking all genes of the Cyp2a, 2b, 2f, 2g, and 2s subfamilies), CYP2A13/2F1-humanized, and liver-Cpr-null (LCN) mice showed that although hepatic cytochrome P450 (P450) enzymes are essential for systemic clearance of inhaled naphthalene (a possible human carcinogen), both hepatic and extrahepatic P450 enzymes may contribute to naphthalene-induced lung toxicity via bioactivation. Herein, we aimed to further understand the toxicokinetics of inhaled naphthalene in order to provide a basis for predicting the effects of variations in rates of xenobiotic disposition on the extent of target tissue bioactivation. We assessed the impact of a hepatic deficit in naphthalene metabolism on the toxicokinetics of inhaled naphthalene using newly generated Cyp2abfgs-null-and-LCN and CYP2A13/2F1-humanized-and-LCN mice. We determined plasma, lung, and liver levels of naphthalene and naphthalene-glutathione conjugate, a biomarker of naphthalene bioactivation, over time after naphthalene inhalation. We found that the loss of hepatic naphthalene metabolism severely decreased naphthalene systemic clearance and caused naphthalene to accumulate in the liver and other tissues. Naphthalene release from tissue, as evidenced by the continued increase in plasma naphthalene levels after termination of active inhalation exposure, was accompanied by prolonged bioactivation of naphthalene in the lung. In addition, transgenic expression of human CYP2A13/2F1 in the respiratory tract caused a reduction in plasma naphthalene levels (by 40%, relative to Cyp2abfgs-null-and-LCN mice) and corresponding decreases in naphthalene-glutathione levels in the lung in mice with hepatic P450 deficiency, despite the increase in local naphthalene-bioactivating P450 activity. Thus, the bioavailability of naphthalene in the target tissue has a significant effect on the extent of naphthalene bioactivation in the lung. SIGNIFICANCE STATEMENT: In this study, we report several novel findings related to the toxicokinetics of inhaled naphthalene, the ability of which to cause lung carcinogenesis in humans is a current topic for risk assessment. We show the accumulation of naphthalene in the liver and lung in mice with compromised hepatic cytochrome P450 (P450) activity; the ability of tissue-stored naphthalene to redistribute to the circulation after termination of active inhalation exposure, prolonging exposure of target tissues to naphthalene; and the ability of non-CYP2ABFGS enzymes of the lung to bioactivate naphthalene. These results suggest potentially large effects of deficiencies in hepatic P450 activity on naphthalene tissue burden and bioactivation in human lungs.

Metabolism and Lung Toxicity of Inhaled Naphthalene: Effects of Postnatal Age and Sex.

Human exposure to naphthalene (NA), an acute lung toxicant and possible human carcinogen, is primarily through inhalation. Acute lung toxicity and carcinogenesis are thought to be related because the target sites for both are similar. To understand susceptibility of the developing lung to cytotoxicity of inhaled NA, we exposed neonatal (7 days), juvenile (3 weeks), and adult mice to 5 or 10 ppm NA vapor for 4 h. We measured vacuolated airway epithelium morphometrically, quantified NA and NA-glutathione levels in plasma and lung, and quantified gene expression in microdissected airways. NA inhalation caused airway epithelial cytotoxicity at all ages, in both sexes. Contrary to a previous study that showed the greatest airway epithelial cytotoxicity in neonatal mice following intraperitoneal NA injection, we observed the most extensive airway epithelial toxicity in older, juvenile, animals exposed to NA by inhalation. Juvenile female animals were the most susceptible. Furthermore, NA inhalation in juvenile animals resulted in damage to conducting airway Club cells that was greater in proximal versus distal airways. We also found NA tissue burden and metabolism differed by age. Gene expression pathway analysis was consistent with the premise that female juvenile mice are more predisposed to damage; DNA damage and cancer pathways were upregulated. Our data demonstrate special susceptibility of young, juvenile mice to NA inhalation-induced cytotoxicity, highlight the importance of route of exposure and airway location in toxicity of chemicals in the developing lung, and provide metabolic and molecular insights for further identification of mechanisms underlying age and sex differences in NA toxicity.

Polychlorinated naphthalenes in human serum samples from an industrial city in Eastern China: Levels, sources, and sex differences.

Polychlorinated naphthalenes (PCNs) in the environment in China have been studied extensively. However, there have been no reports on PCNs in human serum samples from China. In this context, we collected 480 serum samples from an industrial city in Eastern China. The concentration range for the sum of the mono-to octa-CNs was 14300-50700 pg/g lipid. The most predominant congener was CN-5/7, which accounted for 21.6%-51.1% of the total PCN concentration. Further analysis indicated that residues of PCN industrial technical products in the local environment appear to be the main source of CN-5/7 in the serum samples. On the other hand, the sum of the tetra-to octa-CNs concentration was obviously higher in males (1390 ±â€¯929 pg/g lipid) than in females (267 ±â€¯25 pg/g lipid). Moreover, the concentrations of combustion-related PCNs in the male 20-24, 25-29 and 30-34 years groups were obviously higher than those in the female samples. Therefore, industrial thermal processes are important sources of PCNs in male serum in addition to PCN products. The toxic equivalent (TEQ) concentrations of PCNs in the pooled serum samples ranged from 0.12 to 0.40 pg/g lipid. CN-10 and CN-66/67 were the dominant TEQ congeners in male serum, and CN-10, CN-1, and CN-2 were the main TEQ congeners in female serum.

Effect of Wuziyanzong pill on metabolism of dapoxetine in vivo and in vitro.

In vitro incubation of rat liver microsomes with 30 µL of 100 µmol·L-1 dapoxetine and 30 µL of 10, 100, 250, 500, 1000, 2500, or 5000 µg·mL-1 Wuziyanzong pill was performed at 37 °C for 60 min. Dapoxetine concentration was analyzed by high performance liquid chromatography (HPLC). The half maximal inhibitory concentration (IC50) of Wuziyanzong pill on metabolism of dapoxetine was 296.10 µg mL-1in vitro. Twelve SD rats were randomly divided into 2 groups: Control group and Wuziyanzong pill group. The two groups were administrated with 10 mL·kg-1 saline (Control group) or 10 mL·kg-1 Wuziyanzong pill solution (Experimental group, solution contained 200 mg mL-1 Wuziyanzong pill) for 15 consecutive days. Following administration of saline or Wuziyanzong pill on the 15th day, 20 mg kg-1 dapoxetine was administered to all rats. Blood was collected from the tail vein (0.3 mL) at multiple time points, and ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was used to determine the concentration of dapoxetine and its main metabolites, dapoxetine-N-oxide and desmethyldapoxetine in rats. Pharmacokinetic analysis of dapoxetine showed that area under the concentration-time curve (AUC) and mean maximum plasma concentration (Cmax) of the Wuziyanzong pill group were decreased, while plasma clearance (CLz) was increased compared with control group (P < 0.01). The HPLC method for determination of dapoxetine in vitro was accurate and specific. The UHPLC-MS/MS method established for determination of dapoxetine and its major metabolites in rat plasma was rapid and specific, which met the requirements of pharmacokinetic guidelines. Wuziyanzong pill had a weak inhibitory effect on metabolism of dapoxetine in vitro, but had a very strong induction effect in vivo, suggesting the dosage of dapoxetine should be increased when administered in combination with Wuziyanzong pill.

The distribution and excretion of 1-Methylnaphthalene in rats exposed to 1-Methylnaphthalene by inhalation.

OBJECTIVES: 1-Methylnaphthalene (1-MN) is a constituent of polycyclic aromatic hydrocarbons, the chemicals that have become ubiquitous in the environment as result of natural and industrial process. This paper reports a study on the distribution and excretion of 1-MN in rats after single and repeated inhalation exposure to 1-MN vapor. MATERIAL AND METHODS: Male Wistar rats were exposed to 1-MN vapor at nominal concentrations of 50 mg/m3 or 200 mg/m3 in the dynamic inhalation chambers (TSE Systems Head Nose Only Exposure) for 6 h (single exposure) or 5 days (6 h/day, repeated exposure). Blood, urine and tissue samples were collected during and after the exposure. Blood, urine and tissue concentrations of 1-MN were estimated by gas chromatography using the headspace technique. RESULTS: The elimination of 1-MN from blood followed an open 2-compartment model. The concentration in rat tissues was dependent on the magnitude and time of exposure. After repeated exposure, the concentration 1-MN in tissue decreased in comparison to single exposure. The elimination of 1-MN with urine after single and repeated exposure to 1-MN occurred mainly in the samples collected during the first day of collection. CONCLUSIONS: 1-Methylnaphthalene was rapidly eliminated from the blood and tissues of animals exposed by inhalation to 1-MN. In repeated exposure, there was probably a significant increase of 1-MN metabolism in rats exposed to low and high 1-MN doses. Under conditions of repeated 1-MN exposure, no significant systemic 1-MN accumulation could be observed. Int J Occup Med Environ Health 2018;31(6):763-770.

A case of intoxication with a mixture of synthetic cannabinoids EAM-2201, AB-PINACA and AB-FUBINACA, and a synthetic cathinone α-PVP.

We report a case of intoxication with a mixture of three synthetic cannabinoids and a synthetic cathinone, which have been disclosed by a highly sensitive progressing technology. A man was found dead, and his forensic autopsy was performed at our department. After further examinations of his specimens, EAM-2201 and α-PVP have been newly found in his lung. The concentrations of EAM-2201 have not been reported yet in any authentic human specimens although its existence (not quantified) in blood was reported in 2015. Therefore, a sensitive quantitation method of these compounds in blood and solid tissues has been devised using the sensitive instrument. The limits of detection of these compounds were in the range of 3-10 pg/ml with their quantification range of 10-1000 pg/ml in blood. The femoral vein blood levels of EAM-2201 and AB-PINACA were 56.6 ±â€¯4.2 and 12.6 ±â€¯0.1 pg/ml, respectively, and AB-FUBINACA could be detected but not quantifiable in the blood specimens; α-PVP could not be detected. The standard addition method was employed for the quantification of these compounds in the lung, liver and kidney specimens. The lung levels of EAM-2201, AB-PINACA, AB-FUBINACA and α-PVP were 348 ±â€¯34, 355 ±â€¯30, 124 ±â€¯12 and 59.0 ±â€¯7.4 pg/g, respectively. In conclusion, in this study, the concentrations of EAM-2201 in authentic human specimens including blood and solid tissues and those of AB-PINACA and AB-FUBINACA in solid tissue specimens were quantified for the first time to our knowledge.

Distribution of polychlorinated naphthalenes (PCNs) in the whole blood of typical meat animals.

The concentrations and distribution of polychlorinated naphthalenes (PCNs) in the whole blood of eight typical terrestrial meat animals (chicken, duck, rabbit, pig, cattle, sheep, horse and donkey) consumed daily in our life were investigated. The total concentrations (on a liquid volume basis) of PCNs were in a range from 305 to 987pg/L. Donkey blood contained the highest PCN concentrations. Mono-CNs were the dominant homolog group, accounting for 38%-71% PCNs. Apart from the mono-CNs and tri-CNs homolog groups, two hepta-CNs (mean: 9.5%) contributed most, followed by tetra-CNs (mean: 6.5%). The congeners CN1, 5/7, 24/14, 27/30, 52/60, 66/67, and 73 were the most abundant congeners or congener groups. The highest toxicity equivalencies (TEQs) were observed in cattle blood (117.4fg TEQ/L) then chicken blood (117.1fg TEQ/L). CN73 contributed 65% to total TEQs, followed by CN70 (20%) and CN66/67 (14%). The dietary intakes of PCNs were also estimated. Chicken meat, which forms the second largest component of meat product consumption in China, contributed most to the total TEQs (61%), followed by beef (27%) and pork (5.9%). The consumption of chicken might pose the highest risk from exposure to PCNs than other types of meat to populations who prefer to eat chicken meat.

Self-assembled biodegradable polymeric micelles to improve dapoxetine delivery across the blood-brain barrier.

BACKGROUND: Dapoxetine (DPX) is the drug of choice for the specific treatment of premature ejaculation. DPX is characterized by relatively low bioavailability (42%) and short half-life (1.5 h). The aim of this study was to improve DPX bioavailability and delivery across the blood-brain barrier (BBB) using a nanostructured DPX formulation for improved DPX efficacy and patient satisfaction. MATERIALS AND METHODS: DPX-loaded polymeric micelles (PMs) formulations (F1-F3) were characterized for particle sizes, entrapment efficiencies, and Fourier transform infrared spectroscopic and transmission electron microscopic evaluations. In addition, diffusion profiles of the prepared formulations were investigated. Animal model pharmacokinetic parameters in plasma and brain tissues were investigated and compared with commercial DPX tablets. RESULTS: Particle size analysis revealed that formulations of DPX PMs showed a narrow range of 62.7±9.3-45.45±9.1 nm for F1-F3. In addition, DPX PMs showed a sustained release pattern with 91.27%±7.64%, 79.43%±7.81%, and 63.78%±5.05% of DPX content permeated after 24 h for F1, F2, and F3, respectively. Plasma pharmacokinetic parameters for DPX PMs showed significant increase (P<0.05) for the area under drug concentration-time curves in plasma and brain tissues compared with commercial DPX tablets. CONCLUSION: DPX formulations in the form of PMs improved bioavailability and efficacy across the BBB. This DPX formulation provided improved brain delivery in order to enhance the convenience and compliance of patients.

The effect of prenatal exposure on disposition of hexachloronaphthalene in female Wistar rats and fetal compartment.

OBJECTIVES: Due to structural and toxicological similarities to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), polychlorinated naphthalenes (PCNs) were included in the Stockholm Convention on Persistent Organic Pollutants (POPs) in 2015. Hexachloronaphthalene (HxCN) is considered to be one of the most toxic congeners of PCNs. The objective of this study was to determine the maternal and fetal tissue concentrations of hexachloronaphthalene after a single administration. MATERIAL AND METHODS: Pregnant female Outbred Wistar rats were used for the study. The [14C]-HxCN was administered in a single oral dose of 0.3 mg/rat (150 kBq/rat) on gestational day 17 (GD17), GD18 or GD19. All dams were sacrificed on GD20. The blood and selected tissue samples taken from mothers and fetuses 24 h, 48 h or 72 h after exposure were evaluated for the distribution of HxCN. RESULTS: Maximum concentrations of HxCN in pregnant rats were found in the liver and adipose tissue. Relatively high levels of HxCN were also reported in the spleen, ovaries, adrenal glands and uterus, as well as in the sciatic nerve, brain and kidneys. Hexachloronaphthalene penetrates through the blood-brain barrier (BBB), as evidenced by twice the concentration in the brain compared to the blood concentration, and through the placental barrier, as indicated by the level of maternal-fetal compartment (placenta, amniotic fluid, litter). Among the examined fetal tissues, the highest levels of HxCN were found in the kidneys and in the brain. The concentrations in these organs were higher than that found in the maternal blood. CONCLUSIONS: This paper is the first to detail the concentrations of HxCN in the maternal tissues and the transplacental transfer of the tested compound to the fetuses. The exposure of pregnant rats to HxCN results in its accumulation in the maternal liver, fat tissue, reproductive and nervous system, and particularly in the fetal brain. This demonstrates both the effective absorption and significant systemic accumulation which could lead to negative health implications. Int J Occup Med Environ Health 2018;31(5):685-695.

Cystinyl and pyroglutamyl-beta-naphthylamide hydrolyzing activities are modified coordinately between hypothalamus, liver and plasma depending on the thyroid status of adult male rats.

The hypothalamus determinates metabolic processes in liver through endocrine and autonomic control. Hypothalamic neuropeptides, such as thyrotropin releasing hormone or vasopressin, have been involved in liver metabolism. The thyroid status influences metabolic processes including liver metabolism in modulating those hypothalamic peptides whose functional status is regulated in part by aminopeptidase activities. In order to obtain data for a possible coordinated interaction between hypothalamus, plasma and liver, of some aminopeptidase activities that may partially reflect the hydrolysis of those peptides, pyroglutamyl- (pGluAP) and cystinyl- (CysAP) beta-naphthylamide hydrolyzing activities were determined fluorimetrically, both in their soluble and membrane-bound forms, in eu- hypo- and hyperthyroid adult male rats. Hyperthyroidism and hypothyroidism were induced with daily subcutaneous injections of tetraiodothyronine (300 µg/kg/day) or with 0.03% methimazole in drinking water for 6 weeks. Results demonstrated significant changes depending on the type of enzyme and the thyroid status. The most striking changes were observed for CysAP in liver where it was reduced in hypothyroidism and increased in hyperthyroidism. Significant intra- and inter-tissue correlations were observed. While there were positive inter-tissue correlations between liver, plasma and hypothalamus in eu-and hypothyroid rats, a negative correlation between hypothalamus and liver was observed in hyperthyroidism. These results suggest the influence of thyroid hormones and an interactive role for these activities in the control of liver metabolism. The present data also suggest a role for CysAP and pGluAP activities in liver function linked to their activities in hypothalamus.

Bioanalysis of ibrutinib, and its dihydrodiol- and glutathione cycle metabolites by liquid chromatography-tandem mass spectrometry.

Ibrutinib is a targeted covalent inhibitor frequently used for the treatment of various lymphomas. In addition to oxidative metabolism, it is metabolized through glutathione coupling. The quantitative insight into this kind of metabolism is scarce, and tools for quantitation are lacking. The non-oxidative metabolism could prove a more prominent role when oxidative metabolism is impaired. Also, in-vitro studies could over-estimate the effect of CYP450-inhibition. To gain quantitative insight into this relatively unknown biotransformation pathway of the drug we have developed a validated simple, fast and sensitive bio-analytical assay for ibrutinib, dihydrodiol-ibrutinib, and the glutathione, cysteinylglycine and cysteine conjugates of ibrutinib in human plasma. The method emphasizes on simplicity, the thiol-conjugates were synthesized by a simple one step synthesis, followed by LC-purification. Sample preparation was done by a simple protein crash with acetonitrile containing labeled internal standards, evaporation of solvents, and reconstitution in eluent. Finally, the compounds were quantified using UHPLC-MS/MS. The assay was successfully validated in a 0.5-500nM calibration range for all compounds, and also a lower range of 0.05-50 nM was demonstrated for ibrutinib to accommodate for even the lowest trough levels. This assay has a considerably higher sensitivity than previous published assays, with the previous lowest LLOQ being 1.14 nM. Both, ibrutinib, dihydrodiol-ibrutinib and the cysteine conjugate were deemed stable under refrigerated or frozen storage conditions. At room temperature, the glutathione conjugate showed rapid degradation into the cysteinylglycine conjugate in plasma. Finally, the applicability of the assay was demonstrated in patient samples.