Pharmacokinetic profile of metabolites by heart-cutting two-dimensional liquid chromatography: A focus on paracetamol analysis

Therapeutic drug monitoring of paracetamol (acetaminophen, N-acetyl-p-aminophenol, APAP) metabolites in plasma and serum samples was conducted using two-dimensional liquid chromatography (2D-LC) by means of online heart-cutting passive modulation. The selective and efficient 2D-LC approach here developed was applied for the simultaneous determination of six paracetamol metabolites: its major metabolite, the glucuronide conjugate (APAP-GLUC), and its main transformation product p-aminophenol (PAP), along with the bioactive N-arachidonoylphenolamine (AM404), the reactive hepatotoxic N-Acetyl-p-benzoquinone imine (NAPQI), in addition to glutathione (APAP-GLUT) and protein-derived cysteine (APAP-CYS) conjugates. Online heart-cutting mode allowed the combination of C18 reversed-phase column in the first dimension and a Primesep SB analytical column (C18-anion exchange) in the second dimension promoting the effective separation of such different paracetamol metabolites, ranging from highly polar to extremely hydrophobic. The results suggest the promising potential of the proposed 2D-LC methodology for therapeutic drug analysis and pharmacokinetic studies.

Two chromatographic methods for analyzing paracetamol in spiked human plasma with its toxic metabolite, N-acetyl parabenzoquinone imine and its antidote, N-acetyl-L-cysteine

Acetaminophen, also known as paracetamol (APAP), is a highly utilized pharmaceutical agent on a global scale, particularly in the field of pediatrics. Regrettably, an overdose of APAP, resulting from the predominant oxidation, has the potential to trigger acute liver injury. The study's goal was to find an easy, accurate, and selective way to measure APAP, N-acetyl para benzoquinone imine (NAPQI) (an APAP metabolite that is harmful), and N-acetyl-L-cysteine (NAC) (an antidote). Two different chromatographic methods were used. The HPTLC method, which used silica gel 60 F254 as a stationary phase and a developing liquid made up of methanol, ethyl acetate, and glacial acetic acid (8:2:0.2, v/v/v) and a UV detection at 254 nm. The HPLC method was developed using a mobile phase consisting of water, methanol, and formic acid in a proportion of (70:30:0.15, v/v/v). The stationary phase used in the approach was a C18 column. Analytes quantification was established utilizing a UV detector operating at a wavelength of 254 nm. The present methods make it possible to measure the amount of APAP in plasma samples. When it comes to pharmacokinetics or medication levels in children's plasma, for example, this may be also very helpful. The current methods can quantify NAPQI, which is helpful in figuring out drug concentrations in individuals with APAP intoxication diagnoses. Additionally, the current approaches can estimate NAC as an antidote; as a result, this study is a complete study because it can analyse drug, toxic metabolite, and antidote in one analytical run. Using the innovative blue applicability grade index software, which measures the practicality of procedures, both methodologies were compared with a reported methods. Additionally, the achievement of the eco-friendliness profile of the designed procedures was assessed. Both techniques passed the ICH validation tests.

Differently Processed Low Doses of β-Glucan from Oat Bran Similarly Attenuate Postprandial Glycemic Response

Incorporating β-glucan-rich oat bran (OB) can attenuate postprandial glycemic response (PPGR) in solid foods, but its effect in liquid matrices is unclear. This study investigated the ability of differently processed low-dose-β-glucan-containing beverages to lower PPGR, and the mechanisms of action. Twenty participants consumed five malt beverages made from cocoa powder: intact OB (Intact), OB treated with enzymatic hydrolysis (EnzymA, EnzymB) or extrusion (Extr), or no OB (Ctrl). Four-hour postprandial incremental areas under the curve (iAUC) and peak incremental concentrations (iCmax) of glucose, insulin, glucagon-like peptide 1 (GLP-1), gastric inhibitory polypeptide (GIP), and paracetamol were evaluated. The molecular weight (MW) and extractability of the β-glucan in all the test products were also assessed. The three-hour glucose iAUC significantly decreased by -26%, -28%, -32%, and -38% in Intact, EnzymA, EnzymB, and Extr, respectively, and the insulin levels of the oat-containing products were also significantly lower compared to Ctrl. Intact and Extr elicited a lower insulin iCmax and GLP-1 3 h iAUC compared to Ctrl. However, the GIP and paracetamol levels were not changed. All the processed OBs improved β-glucan extractability and lowered the MW of β-glucan compared to Intact. In conclusion, low-dose oat β-glucan in a beverage significantly reduced PPGR, with effects maintained across different oat processing methods.

Rapid Characterization of Undeclared Pharmaceuticals in Herbal Preparations by Ambient Ionization Mass Spectrometry for Emergency Care

In Asia, some herbal preparations have been found to be adulterated with undeclared synthetic medicines to increase their therapeutic efficiency. Many of these adulterants were found to be toxic when overdosed and have been documented to bring about severe, even life-threatening acute poisoning events. The objective of this study is to develop a rapid and sensitive ambient ionization mass spectrometric platform to characterize the undeclared toxic adulterated ingredients in herbal preparations. Several common adulterants were spiked into different herbal preparations and human sera to simulate the clinical conditions of acute poisoning. They were then sampled with a metallic probe and analyzed by the thermal desorption-electrospray ionization mass spectrometry. The experimental parameters including sensitivity, specificity, accuracy, and turnaround time were prudently optimized in this study. Since tedious and time-consuming pretreatment of the sample is unnecessary, the toxic adulterants could be characterized within 60 s. The results can help emergency physicians to make clinical judgments and prescribe appropriate antidotes or supportive treatment in a time-sensitive manner.

Emergency diagnosis made easy: matrix removal and analyte enrichment from raw saliva using paper-arrow mass spectrometry

Paracetamol overdose is a leading cause of acute liver failure that can prove fatal. Establishing paracetamol concentration accurately and quickly is critical. Current detection methods are invasive, time-consuming and/or expensive. Non-invasive, rapid and cost-effective techniques are urgently required. To address this challenge, a novel approach, called Paper-Arrow Mass Spectrometry (PA-MS) has been developed. This technique combines sample collection, extraction, enrichment, separation and ionisation onto a single paper strip, and the entire analysis process, from sample to result, can be carried out in less than 10 min requiring only 2 μL of raw human saliva. PA-MS achieved a LOQ of 185 ng mL-1, mean recovery of 107 ± 7%, mean accuracy of 11 ± 8% and precision ≤5% using four concentrations, and had excellent linearity (r2 = 0.9988) in the range of 0.2-200 μg mL-1 covering the treatment concentration range, surpassing the best-in-class methods currently available for paracetamol analysis. Furthermore, from a panel of human saliva samples, inter-individual variability was found to be <10% using this approach. This technique represents a promising tool for rapid and accurate emergency diagnosis.

Simultaneous determination of tramadol and paracetamol in human plasma using LC-MS/MS and application in bioequivalence study of -fixed-dose combination

The study aimed to develop a sensitive and high-throughput liquid chromatography coupled with tandem mass spectrometry method to quantify concentrations of tramadol and paracetamol simultaneously in human plasma. Sample preparation involved single-step protein precipitation using methanol and two deuterated internal standards, tramadol D6 and paracetamol D4. Agilent Poroshell 120 EC-C18 (100 × 2.1 mm, 2.1 µm) analytical column was employed to achieve chromatographic separation. Detection was in positive ion multiple reaction monitoring mode. A tailing factor (Tf) of <1.2, separation factor (K prime) of >1.5 from the column dead time and signal-to-noise (S/N) ratio >10, were obtained for analytes and internal standards. The standard curve was linear over the concentration range of 2.5-500.00 ng/mL for tramadol and 0.025-20.00 μg/mL for paracetamol. A small injection volume of 1 µL, low flow rate of 440 µL/min and short analysis time of 3.5 min reduced the solvent consumption, analysis cost and system contamination. The results of method validation parameters fulfilled the acceptance criteria of bioanalytical guidelines. The method was successfully applied to a bioequivalence study of fixed-dose combination products of tramadol and paracetamol in Malaysian healthy subjects.

Analysis of AT7519 as a pro-resolution compound in an acetaminophen-induced mouse model of acute inflammation by UPLC-MS/MS

BACKGROUND

Uncontrolled inflammation contributes to the progression of organ damage in acute conditions, such as acetaminophen-induced acute liver injury (APAP-ALI) and there are limited treatments for this condition. AT7519, a cyclic-dependent kinase inhibitor (CDKI), has been used successfully in several conditions, to resolve inflammation and return tissue homeostatic functions. AT7519 has not been assessed in APAP-ALI and its effect on APAP metabolism is unknown. Targeted chromatography and mass spectrometry can be used to assess multiple compounds simultaneously and this approach has not been applied yet to measure APAP and AT7519 in a mouse model.

RESULTS

We show an optimised simple and sensitive LC-MS/MS method for determining concentrations of AT7519 and APAP in low volumes of mouse serum. Using positive ion mode electrospray ionisation, separation of AT7519 and APAP and their corresponding isotopically labelled internal standards [2H]8-AT16043M (d8-AT7519) and [2H]8-APAP (d4-APAP), was achieved on an Acquity UPLC BEH C18 column (100 × 2.1 mm; 1.7μm). A gradient mobile phase system of water and methanol was delivered at a flow rate of 0.5 mL/min with a run time of 9 min. Calibration curves were linear, intra-day and inter-day precision and accuracy were acceptable and the covariates of all standards and quality control replicates were less than 15%. The method was successfully applied to evaluate AT7519 and APAP levels 20 h post AT7519 (10 mg/mg) in C57Bl6J wild type mouse serum treated with either vehicle or APAP. Serum AT7519 was significantly higher in mice that had received APAP compared to control, but there was no correlation between APAP and AT7519 quantification. There was also no correlation of AT7519 and hepatic damage or proliferation markers.

CONCLUSION

We optimised an LC-MS/MS method to quantify both AT7519 and APAP in mouse serum (50 µL), using labelled internal standards. Application of this method to a mouse model of APAP toxicity proved effective in accurately measuring APAP and AT7519 concentrations after i.p. dosing. AT7519 was significantly higher in mice with APAP toxicity, indicating hepatic metabolism of this CDKI, but there was no correlation with markers of hepatic damage or proliferation, demonstrating that this dose of AT7519 (10 mg/kg) does not contribute to hepatic damage or repair. This optimised method can be used for future investigations of AT7519 in APAP in mice.

Suspect screening of exogenous compounds using multiple reaction screening (MRM) profiling in human urine samples

Thousands of chemical compounds produced by industry are dispersed in the human environment widely enough to reach the world population, and the introduction of new chemicals constantly occurs. As new synthetic molecules emerge, rapid analytical workflows for screening possible presence of exogenous compounds in biofluids can be useful as a first pass analysis to detect chemical exposure and guide the development and application of more elaborate LC-MS/MS methods for quantification. In this study, a suspect screening workflow using the multiple reaction monitoring (MRM) profiling method is proposed as a first pass exploratory technique to survey selected exogenous molecules in human urine samples. The workflow was applied to investigate 12 human urine samples using 310 MRMs related to the chemical functionalities of 87 exogenous compounds present in the METLIN database and reported in the literature. A total of 11 MRMs associated with five different compounds were detected in the samples. Product ion scans for the precursor ions of the selected MRMs were acquired as a further identification step for these chemicals. The suspect screening results suggested the presence of five exogenous compounds in the human urine samples analyzed, namely metformin, metoprolol, acetaminophen, paraxanthine and acrylamide. LC-MS/MS was applied as a last step to confirm these results, and the presence of four out of the five targets selected by MRM profiling were corroborated, indicating that this workflow can support the selection of suspect compounds to screen complex samples and guide more time-consuming and specific quantification analyses.

Acetaminophen (APAP, Paracetamol) Interferes With the First Trimester Human Fetal Ovary Development in an Ex Vivo Model

CONTEXT

Acetaminophen (APAP, paracetamol) is widely used by pregnant women. Although long considered safe, growing evidence indicates that APAP is an endocrine disruptor since in utero exposure may be associated with a higher risk of male genital tract abnormalities. In rodents, fetal exposure has long-term effects on the reproductive function of female offspring. Human studies have also suggested harmful APAP exposure effects.

OBJECTIVE

Given that disruption of fetal ovarian development may impact women's reproductive health, we investigated the effects of APAP on fetal human ovaries in culture.

DESIGN AND SETTING

Human ovarian fragments from 284 fetuses aged 7 to 12 developmental weeks (DW) were cultivated ex vivo for 7 days in the presence of human-relevant concentrations of APAP (10-8 to 10-3 M) or vehicle control.

MAIN OUTCOME MEASURES

Outcomes included examination of postculture tissue morphology, cell viability, apoptosis, and quantification of hormones, APAP, and APAP metabolites in conditioned culture media.

RESULTS

APAP reduced the total cell number specifically in 10- to 12-DW ovaries, induced cell death, and decreased KI67-positive cell density independently of fetal age. APAP targeted subpopulations of germ cells and disrupted human fetal ovarian steroidogenesis, without affecting prostaglandin or inhibin B production. Human fetal ovaries were able to metabolize APAP.

CONCLUSIONS

Our data indicate that APAP can impact first trimester human fetal ovarian development, especially during a 10- to 12-DW window of heightened sensitivity. Overall, APAP behaves as an endocrine disruptor in the fetal human ovary.

Alterations in circadian rhythms aggravate Acetaminophen-induced liver injury in mice by influencing Acetaminophen metabolization and increasing intestinal permeability

Acetaminophen (APAP) is the most common antipyretic and analgesic drug causing drug-induced liver injury (DILI). Alterations in circadian rhythms can adversely affect liver health, especially metabolic and detoxification functions. However, the effect of circadian rhythm alterations induced by environmental factors on APAP-induced liver injury and the underlying mechanisms are not well known. In this study, a mouse model of circadian rhythm alterations was established by light/dark cycle shift and then treated with excessive APAP. The liver injury indexes, APAP-related metabolic enzymes, and intestinal permeability in mice were evaluated by biochemical analysis, quantitative real-time PCR, enzyme-linked immunosorbent assays, and histopathology. Results showed that circadian rhythm alterations resulted in increased reactive oxygen species (ROS) and malondialdehyde (MDA) and decreased liver superoxide dismutase (SOD), glutathione, and CYP1A2 and CYP3A11 mRNA expression, and increased serum diamine oxidase, lipopolysaccharide, and D-lactate in the mice. Compared with control mice, APAP induced higher serum alanine aminotransferase and aspartate aminotransferase, liver interleukin-1β and tumor necrosis factor-α mRNA, ROS and MDA, lower SOD, glutathione, and UDP-glucuronosyltransferases /sulfotransferases mRNA and more severe liver necrosis and intestinal damage in mice with alterations in circadian rhythms. In conclusion, circadian rhythm alterations by light/dark cycle shift resulted in increased oxidative stress and intestinal permeability in the mice and exacerbated APAP-induced liver injury by influencing APAP metabolization and increasing intestinal permeability.

Redefining IL11 as a regeneration-limiting hepatotoxin and therapeutic target in acetaminophen-induced liver injury

Acetaminophen (N-acetyl-p-aminophenol; APAP) toxicity is a common cause of liver damage. In the mouse model of APAP-induced liver injury (AILI), interleukin 11 (IL11) is highly up-regulated and administration of recombinant human IL11 (rhIL11) has been shown to be protective. Here, we demonstrate that the beneficial effect of rhIL11 in the mouse model of AILI is due to its inhibition of endogenous mouse IL11 activity. Our results show that species-matched IL11 behaves like a hepatotoxin. IL11 secreted from APAP-damaged human and mouse hepatocytes triggered an autocrine loop of NADPH oxidase 4 (NOX4)-dependent cell death, which occurred downstream of APAP-initiated mitochondrial dysfunction. Hepatocyte-specific deletion of Il11 receptor subunit alpha chain 1 (Il11ra1) in adult mice protected against AILI despite normal APAP metabolism and glutathione (GSH) depletion. Mice with germline deletion of Il11 were also protected from AILI, and deletion of Il1ra1 or Il11 was associated with reduced c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) activation and quickly restored GSH concentrations. Administration of a neutralizing IL11RA antibody reduced AILI in mice across genetic backgrounds and promoted survival when administered up to 10 hours after APAP. Inhibition of IL11 signaling was associated with the up-regulation of markers of liver regenerations: cyclins and proliferating cell nuclear antigen (PCNA) as well as with phosphorylation of retinoblastoma protein (RB) 24 hours after AILI. Our data suggest that species-matched IL11 is a hepatotoxin and that IL11 signaling might be an effective therapeutic target for APAP-induced liver damage.

Alcohol and drug consumption among motor vehicle drivers in the Brittany region of France: A 9-year cross-sectional population study

The primary objective of the present study was to evaluate the frequency of positive tests for alcohol and drugs during roadside testing or after road accidents among drivers in the Brittany region of France. The study’s secondary objective was to describe the blood concentrations of the substances found during these tests, in order to provide a scientific basis for the establishment or modification of legislative threshold values for road injuries prevention. We performed a cross-sectional study of a database compiled by Rennes University Hospital’s toxicology laboratory in the Brittany region of France between 2010 and 2018. Driver’s age, sex, and test status (positive or negative), and blood levels of ethanol, 9-tetrahydrocannabinol (THC), methylene dioxymethamphetamine (MDMA), amphetamine, benzoylecgonine and 6-monoacetylmorphine (6-MAM) were collected. Twelve thousand four hundred and ninety-seven drivers (males: 86.1%; median (range) age: 29 (15–94)) have provided roadside blood samples, giving a total of 25,998 test results. Among the 10,996 drivers with at least one positive test, the median blood concentrations of ethanol, THC, MDMA, amphetamine, benzoylecgonine, and 6-MAM were respectively 1.82 g/L, 2.41 ng/mL, 138.4 ng/mL, 67.7 ng/mL, 173.3 ng/mL, and 0.97 ng/mL. 1159 (10.54%) of the 10,996 drivers tested positive for two or more substances, and 151 (1.4%) tested positive for three or more substances. With the exception of heroin, the currently recommended threshold values appear to be appropriate for road injuries prevention with regard to the concentrations observed in offenders.

A functional long-term 2D serum-free human hepatic in vitro system for drug evaluation

Human in vitro hepatic models generate faster drug toxicity data with higher human predictability compared to animal models. However, for long-term studies, current models require the use of serum and 3D architecture, limiting their utility. Maintaining a functional long-term human in vitro hepatic culture that avoids complex structures and serum would improve the value of such systems for preclinical studies. This would also enable a more straightforward integration with current multi-organ devices to study human systemic toxicity to generate an alternative model to chronic animal evaluations. A human primary hepatocyte culture system was characterized for 28 days in 2D and serum-free defined conditions. Under the studied conditions, human primary hepatocytes maintained their characteristic morphology, hepatic markers and functions for 28 days. The acute and chronic administration of known drugs validated the sensitivity of the system for drug testing. This human 2D model represents a realistic system to evaluate hepatic function for long-term drug studies, without the need of animal serum, confounding variable in most models, and with less complexity and resultant cost compared to most 3D models. The defined culture conditions can easily be integrated into complex multi-organ in vitro models for studying systemic effects driven by the liver function for long-term evaluations.

The analysis of acetaminophen (paracetamol) and seven metabolites in rat, pig and human plasma by U(H)PLC-MS

A U(H)PLC-MS/MS method is described for the analysis of acetaminophen and its sulphate, glucuronide, glutathione, cysteinyl and N-acetylcysteinyl metabolites in plasma using stable isotope-labeled internal standards. P-Aminophenol glucuronide and 3-methoxyacetaminophen were monitored and semi-quantified using external standards. The assay takes 7.5 min/sample, requires only 5 μl of plasma and involves minimal sample preparation. The method was validated for rat plasma and cross validated for human and pig plasma and mouse serum. LOQ in plasma for these analytes were 0.44 μg/ml (APAP-C), 0.58 μg/ml (APAP-SG), 0.84 μg/ml (APAP-NAC), 2.75 μg/ml (APAP-S), 3.00 μg/ml (APAP-G) and 16 μg/ml (APAP). Application of the method is illustrated by the analysis of plasma following oral administration of APAP to male Han Wistar rats.

Performance evaluation of five commercial assays for detection of acetaminophen

BACKGROUND

To evaluate the analytical performance of five commercial acetaminophen assays and select the best method for routine use.

METHODS

Imprecision, accuracy, linearity, and interferences of three enzymatic assays (Beckman Coulter AU Paracetamol, Abbott MULTIGENT Acetaminophen, and Sekisui Acetaminophen L3K) and two immunoassay-based assays (Beckman Coulter SYNCHRON ACTM (Acetaminophen) Reagent and Siemens SYVA Emit-tox Acetaminophen) were evaluated on a Beckman Coulter AU680 chemistry analyzer. Hook effect for immunoassay-based assays and recovery in ultrafiltrate for enzymatic methods were studied.

RESULTS

Within-run and between-run imprecision of the enzymatic assays ranged 0.26%-0.82% and 0.53%-2.86%, respectively, while that for the immunoassay-based methods ranged 0.96%-6.34% and 1.50%-11.33%, respectively. All assays except the SYNCHRON assay fell within the program analytical performance specifications (±20 µmol/L or 10%) for external quality assurance (EQA) samples, with the highest positive bias (31.7%) observed in the SYNCHRON assay. Icteric interference was demonstrated most significantly in the Abbott assay (up to 88 μmol/L positive bias in blank serum). The lipemic interference on the SYNCHRON was significant (up to 110% positive bias at level of 100 μmol/L). The immunoassay-based methods were less susceptible to hemolytic interference, while the Abbott and AU assays were more susceptible to N-acetylcysteine interference. Both immunoassay-based methods showed no hook effect up to 18 000 μmol/L. Ultrafiltration recoveries for enzymatic methods were satisfactory, ranging from 80.0% ± 5.1% to 89.5% ± 3.0%.

CONCLUSIONS

Proportional bias was observed in the SYNCHRON assay, while the Siemens and Sekisui assays were minimally affected by bilirubin interferences.

Quantitation of paracetamol by liquid chromatography-mass spectrometry in human plasma in support of clinical trial

Aim:

Paracetamol is a well-tolerated antipyretic widely used in severe malaria management. The study aimed to develop and validate a rapid LC–MS/MS assay to quantify paracetamol in plasma from patients with severe malaria.

Materials & methods:

Plasma sample was precipitated by organic solvent containing isotope-labeled paracetamol internal standard. Supernatant was isolated, diluted with water, followed by LC–MS/MS analysis.

Results:

Plasma samples were extracted and assayed in less than 5.5 min. The assay response was linear (0.125–50 mg/l) with total intra- and interassay imprecision of <1.4%, which were considerably lower than most published reports.

Conclusion:

We developed, validated and applied a rapid and small volume LC–MS/MS assay with high precision and accuracy for plasma paracetamol quantitation in 989 samples from 62 patients with severe malaria. The simple and high-throughput quality could facilitate assay automation for future clinical studies.

Paracetamol is a commonly prescribed antipyretic in severe malaria management. Here, a rapid quantitative assay was developed to measure the plasma level of paracetamol. The developed method required levels as low as 20 μl plasma, and was highly precise, with a short analysis time of 5.5 min. The developed method is particularly suitable for clinical trial application and potentially for clinical use.

Glucosamine-paracetamol spray-dried solid dispersions with maximized intrinsic dissolution rate, bioavailability and decreased levels of in vivo toxic metabolites

Purpose

This study is aimed at preparing and testing physicochemical, pharmacokinetic and levels of toxic metabolites of paracetamol and glucosamine solid dispersions intended for multiple deliveries via the parenteral or per oral route.

Methods

Solid dispersions were prepared using the spray drying technique at different molar ratios of paracetamol and glucosamine. Characterization of the solid dispersions was carried out using differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), equilibrium solubility and intrinsic dissolution rate. In vivo pharmacokinetics and toxic metabolites of the prepared dispersions were evaluated and compared to those of pure drugs and physical mixtures.

Results

Instant water solubility and more than 7-fold increase in dissolution rate led to significantly high plasma drug concentration (>6.5-fold) compared to paracetamol alone. More than 2-fold increase in area under the curve from 0 to 24 h from the dispersions was noticed on the third day of oral dosing to animals. Lower number and concentration followed by the complete disappearance of toxic pathway metabolites were observed on second and third days of dosing with solid dispersions and physical mixtures, respectively.

Conclusions

The spray-dried dispersions support safer and more effective delivery of multiple doses of paracetamol, leading to an acceleration of its analgesic actions. Synergism between the analgesic actions of paracetamol and joint protective actions of glucosamine in this combination is expected to facilitate effective treatment of persistent pain-related illnesses such as osteoarthritis.

Novel approach for evaluating pharmaceuticals toxicity using Daphnia model: analysis of the mode of cytochrome P450-generated metabolite action after acetaminophen exposure

Because of its widespread use, the pharmaceutical acetaminophen (APAP) is frequently detected in aquatic environments. APAP can have serious physiological effects, such as reduced reproduction, low growth rates, and abnormal behavior, in aquatic organisms. However, the methods available for evaluation of the aquatic toxicity of APAP are of limited usefulness. The present study aimed to develop reliable and sensitive markers for evaluation of APAP toxicity using Daphnia as a model organism. We focused on N-acetyl-p-benzoquinoneimine (NAPQI) production from APAP via cytochrome P450 metabolism because NAPQI causes APAP toxicity. Daphnia magna were exposed to APAP (0, 50, or 100 mg/L for 12 h or 24 h), and the total metabolites were extracted and analyzed for NAPQI. Direct detection of NAPQI was difficult because of its high reactivity, and its peak was close to that for APAP. Therefore, we tried to identify molecular and biochemical indicators associated with NAPQI generation, elimination, and its interactions with macromolecules. We identified changes in CYP370A13 gene expression, glutathione depletion, inhibition of thioredoxin reductase activity, and production of reactive oxygen species as indicators of D. magna exposure to APAP. These indicators could be used to develop sensitive and accurate techniques to evaluate the environmental toxicity of APAP.

The novel, potent and highly selective 5-HT4 receptor agonist YH12852 significantly improves both upper and lower gastrointestinal motility

BACKGROUND AND PURPOSE

5-HT₄ receptor agonists have been shown to be effective at treating various gastrointestinal tract disorders. However, a lack of selectivity against off-targets has been a limiting factor for their clinical use.

EXPERIMENTAL APPROACH

The binding affinity and selectivity of YH12852 for human 5-HT_4(a) receptor in CHO-K1 cells were evaluated using radioligand binding assays, and agonistic activity was assessed using a β-lactamase reporter system. Contractile activity and propulsive motility were measured in the guinea pig isolated distal colon. Its prokinetic effect on the gastrointestinal tract was evaluated in guinea pigs, dogs and monkeys. Its tissue distribution was evaluated in rats.

KEY RESULTS

YH12852 exhibited high affinity and potency for human recombinant 5-HT_4(a) receptor with high selectivity over other 5-HT and non-5-HT receptors, ion channels, enzymes and transporters. YH12852 induced contractions and increased propulsive motility in guinea pig isolated colon. These effects were abolished by the 5-HT₄ receptor antagonist GR113808. YH12852 increased defecation more effectively than prucalopride in guinea pigs and dogs and improved gastric emptying more effectively than mosapride in guinea pigs, dogs and monkeys. YH12852 was highly distributed to the gastrointestinal tract as the target organ.

CONCLUSION AND IMPLICATIONS

The high in vitro potency and selectivity of YH12852 for 5-HT₄ receptor translated into potent in vivo efficacy with good tolerability. YH12852 significantly improved both upper and lower bowel motility in the animal models tested and has the potential to address considerable unmet needs in patients with functional constipation, gastroparesis or both.

Paracetamol: overdose-induced oxidative stress toxicity, metabolism, and protective effects of various compounds in vivo and in vitro

Paracetamol (APAP) is one of the most widely used and popular over-the-counter analgesic and antipyretic drugs in the world when used at therapeutic doses. APAP overdose can cause severe liver injury, liver necrosis and kidney damage in human beings and animals. Many studies indicate that oxidative stress is involved in the various toxicities associated with APAP, and various antioxidants were evaluated to investigate their protective roles against APAP-induced liver and kidney toxicities. To date, almost no review has addressed the APAP toxicity in relation to oxidative stress. This review updates the research conducted over the past decades into the production of reactive oxygen species (ROS), reactive nitrogen species (RNS), and oxidative stress as a result of APAP treatments, and ultimately their correlation with the toxicity and metabolism of APAP. The metabolism of APAP involves various CYP450 enzymes, through which oxidative stress might occur, and such metabolic factors are reviewed within. The therapeutics of a variety of compounds against APAP-induced organ damage based on their anti-oxidative effects is also discussed, in order to further understand the role of oxidative stress in APAP-induced toxicity. This review will throw new light on the critical roles of oxidative stress in APAP-induced toxicity, as well as on the contradictions and blind spots that still exist in the understanding of APAP toxicity, the cellular effects in terms of organ injury and cell signaling pathways, and finally strategies to help remedy such against oxidative damage.

Chronic and low exposure to a pharmaceutical cocktail induces mitochondrial dysfunction in liver and hyperglycemia: Differential responses between lean and obese mice

Pharmaceuticals are found in the environment but the impact of this contamination on human and animal health is poorly known. The liver could be particularly targeted since a significant number of these drugs are hepatotoxic, in particular via oxidative stress and mitochondrial dysfunction. Notably, the latter events can also be observed in liver diseases linked to obesity, so that the obese liver might be more sensitive to drug toxicity. In this study, we determined the effects of a chronic exposure to low doses of pharmaceuticals in wild-type and obese mice, with a particular focus on mitochondrial function. To this end, wild-type and ob/ob mice were exposed for 4 months to a cocktail of 11 pharmaceuticals provided in drinking water containing 0.01, 0.1, or 1 mg/L of each drug. At the end of the treatment, liver mitochondria were isolated and different parameters were measured. Chronic exposure to the pharmaceuticals reduced mitochondrial respiration driven by succinate and palmitoyl-l-carnitine in wild-type mice and increased antimycin-induced ROS production in ob/ob mice. Hyperglycemia and hepatic histological abnormalities were also observed in treated ob/ob mice. Investigations were also carried out in isolated liver mitochondria incubated with the mixture, or with each individual drug. The mitochondrial effects of the mixture were different from those observed in treated mice and could not be predicted from the results obtained with each drug. Because some of the 11 drugs included in our cocktail can be found in water at relatively high concentrations, our data could be relevant in environmental toxicology. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1375-1389, 2017.

Gastric Emptying in Critically Ill Children

BACKGROUND

Delayed gastric emptying (GE) impedes enteral nutrient (EN) delivery in critically ill children. We examined the correlation between (a) bedside EN intolerance assessments, including gastric residual volume (GRV); (b) delayed GE; and (c) delayed EN advancement.

MATERIALS AND METHODS

We prospectively enrolled patients ≥1 year of age, eligible for gastric EN and without contraindications to acetaminophen. Gastric emptying was determined by the acetaminophen absorption test, specifically the area under the curve at 60 minutes (AUC₆₀). Slow EN advancement was defined as delivery of <50% of the prescribed EN 48 hours after study initiation. EN intolerance assessments (GRV, abdominal distension, emesis, loose stools, abdominal discomfort) were recorded.

RESULTS

We enrolled 20 patients, median 11 years (4.4-15.5), 50% male. Sixteen (80%) patients had delayed GE (AUC₆₀ <600 mcg·min/mL) and 7 (35%) had slow EN advancement. Median GRV (mL/kg) for patients with delayed vs normal GE was 0.43 (0.113-2.188) vs 0.89 (0.06-1.91), P = .9635. Patients with slow vs rapid EN advancement had median GRV (mL/kg) of 1.02 mL/kg (0.20-3.20) vs 0.27 mL/kg (0.06-1.62), P = .3114, and frequency of altered EN intolerance assessments of 3/7 (42.9%) vs 5/13 (38.5%), P = 1. Median AUC₆₀ for patients with slow vs rapid EN advancement was 91.74 mcg·min/mL (53.52-143.1) vs 449.5 mcg·min/mL (173.2-786.5), P = .0012.

CONCLUSIONS

A majority of our study cohort had delayed GE. Bedside EN intolerance assessments, particularly GRV, did not predict delayed GE or rate of EN advancement. Delayed gastric emptying predicted slow EN advancement. Novel tests for delayed GE and EN intolerance are needed.

LC-MS/MS method development for quantitative analysis of acetaminophen uptake by the aquatic fungus Mucor hiemalis

Acetaminophen is a pharmaceutical, frequently found in surface water as a contaminant. Bioremediation, in particular, mycoremediation of acetaminophen is a method to remove this compound from waters. Owing to the lack of quantitative analytical method for acetaminophen in aquatic organisms, the present study aimed to develop a method for the determination of acetaminophen using LC-MS/MS in the aquatic fungus Mucor hiemalis. The method was then applied to evaluate the uptake of acetaminophen by M. hiemalis, cultured in pellet morphology. The method was robust, sensitive and reproducible with a lower limit of quantification of 5 pg acetaminophen on column. It was found that M. hiemalis internalize the pharmaceutical, and bioaccumulate it with time. Therefore, M. hiemalis was deemed a suitable candidate for further studies to elucidate its pharmaceutical tolerance and the longevity in mycoremediation applications.

A cellular model to study drug-induced liver injury in nonalcoholic fatty liver disease: Application to acetaminophen

Obesity and nonalcoholic fatty liver disease (NAFLD) can increase susceptibility to hepatotoxicity induced by some xenobiotics including drugs, but the involved mechanisms are poorly understood. For acetaminophen (APAP), a role of hepatic cytochrome P450 2E1 (CYP2E1) is suspected since the activity of this enzyme is consistently enhanced during NAFLD. The first aim of our study was to set up a cellular model of NAFLD characterized not only by triglyceride accumulation but also by higher CYP2E1 activity. To this end, human HepaRG cells were incubated for one week with stearic acid or oleic acid, in the presence of different concentrations of insulin. Although cellular triglycerides and the expression of lipid-responsive genes were similar with both fatty acids, CYP2E1 activity was significantly increased only by stearic acid. CYP2E1 activity was reduced by insulin and this effect was reproduced in cultured primary human hepatocytes. Next, APAP cytotoxicity was assessed in HepaRG cells with or without lipid accretion and CYP2E1 induction. Experiments with a large range of APAP concentrations showed that the loss of ATP and glutathione was almost always greater in the presence of stearic acid. In cells pretreated with the CYP2E1 inhibitor chlormethiazole, recovery of ATP was significantly higher in the presence of stearate with low (2.5mM) or high (20mM) concentrations of APAP. Levels of APAP-glucuronide were significantly enhanced by insulin. Hence, HepaRG cells can be used as a valuable model of NAFLD to unveil important metabolic and hormonal factors which can increase susceptibility to drug-induced hepatotoxicity.

Simultaneous quantification of acetaminophen and five acetaminophen metabolites in human plasma and urine by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry: Method validation and application to a neonatal pharmacokinetic study

Drug metabolism plays a key role in acetaminophen (paracetamol)-induced hepatotoxicity, and quantification of acetaminophen metabolites provides critical information about factors influencing susceptibility to acetaminophen-induced hepatotoxicity in clinical and experimental settings. The aims of this study were to develop, validate, and apply high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) methods for simultaneous quantification of acetaminophen, acetaminophen-glucuronide, acetaminophen-sulfate, acetaminophen-glutathione, acetaminophen-cysteine, and acetaminophen-N-acetylcysteine in small volumes of human plasma and urine. In the reported procedures, acetaminophen-d4 and acetaminophen-d3-sulfate were utilized as internal standards (IS). Analytes and IS were recovered from human plasma (10μL) by protein precipitation with acetonitrile. Human urine (10μL) was prepared by fortification with IS followed only by sample dilution. Calibration concentration ranges were tailored to literature values for each analyte in each biological matrix. Prepared samples from plasma and urine were analyzed under the same HPLC-ESI-MS/MS conditions, and chromatographic separation was achieved through use of an Agilent Poroshell 120 EC-C18 column with a 20-min run time per injected sample. The analytes could be accurately and precisely quantified over 2.0-3.5 orders of magnitude. Across both matrices, mean intra- and inter-assay accuracies ranged from 85% to 112%, and intra- and inter-assay imprecision did not exceed 15%. Validation experiments included tests for specificity, recovery and ionization efficiency, inter-individual variability in matrix effects, stock solution stability, and sample stability under a variety of storage and handling conditions (room temperature, freezer, freeze-thaw, and post-preparative). The utility and suitability of the reported procedures were illustrated by analysis of pharmacokinetic samples collected from neonates receiving intravenous acetaminophen.

Simultaneous determination of acetaminophen and dihydrocodeine in human plasma by UPLC-MS/MS: Its pharmacokinetic application

An ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed and validated to determine acetaminophen (AAP) and dihydrocodeine (DHC) in human plasma simultaneously. Plasma samples were prepared using protein precipitation with acetonitrile, the two analytes and the internal standard midazolam were separated on an Acquity UPLC BEH C18 column and mass spectrometric analysis was performed using a QTrap5500 mass spectrometer coupled with an electro-spray ionization (ESI) source in the positive ion mode. The MRM transitions of m/z 151.2→110.0 and m/z 302.3→199.2 were used to quantify for AAP and DHC, respectively. The linearity of this method was found to be within the concentration range of 50-10000ng/mL for AAP, and 1-100ng/mL for DHC in human plasma, respectively. The lower limit of quantification (LLOQ) was 50ng/mL and 1ng/mL for AAP and DHC in human plasma, respectively. The relative standard deviations (RSD) of intra and inter precision were less than 10% for both AAP and DHC. The analysis time of per sample was 1.0min. The developed and validated method was successfully applied to a pharmacokinetic study of AAP (500mg) with DHC (20mg) capsule in Chinese healthy volunteers (N=20).

Acetaminophen-induced liver injury in obesity and nonalcoholic fatty liver disease

Although acetaminophen (APAP) is usually considered as a safe drug, this painkiller can lead to acute liver failure after overdoses. Moreover, there is evidence that the maximum recommended dosage can induce hepatic cytolysis in some individuals. Several predisposing factors appear to enhance the risk and severity of APAP-induced liver injury including chronic alcoholic liver disease and nonalcoholic fatty liver disease (NAFLD), which refers to a large spectrum of hepatic lesions linked to obesity. In contrast, obesity by itself does not seem to be associated with a higher risk of APAP-induced liver injury. Since 1987, seven studies dealt with APAP-induced hepatotoxicity in rodent models of NAFLD and five of them found that this liver disease was associated with higher APAP toxicity. Unfortunately, these studies did not unequivocally established the mechanism(s) whereby NAFLD could favour APAP hepatotoxicity, although some investigations suggested that pre-existent induction of hepatic cytochrome P450 2E1 (CYP2E1) could play a significant role by increasing the generation of N-acetyl-p-benzoquinone imine (NAPQI), the toxic metabolite of APAP. Moreover, pre-existent mitochondrial dysfunction associated with NAFLD could also be involved. In contrast, some investigations suggested that factors that could reduce the risk and severity of APAP hepatotoxicity in obesity and NAFLD include higher hepatic APAP glucuronidation, reduced CYP3A4 activity and increased volume of body distribution. Thus, the occurrence and the outcome of APAP-induced liver injury in an obese individual with NAFLD might depend on a delicate balance between metabolic factors that can be protective and others that favour large hepatic levels of NAPQI.