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1

Ethyl glucuronide  

Microsoft Academic Search

A marker with a specific time spectrum of detection and both high sensitivity and specificity is required to diminish the clinically as well as forensically important gap on the time axis between short- and long-term markers of alcohol consumption like ethanol and CDT, GGT or MCV, respectively. Ethyl glucuronide (EtG) is a non-volatile, water-soluble, stable upon storage, direct metabolite of

Friedrich Martin Wurst; Christoph Kempter; Joerg Metzger; Stephan Seidl; Andreas Alt

2000-01-01

2

A novel and an effective analytical approach for the LCMS determination of ethyl glucuronide and ethyl sulfate in urine  

Microsoft Academic Search

An alternative liquid chromatography-mass spectrometry (LC-MS) method based on no discharge (ND) atmospheric pressure chemical ionization (APCI) was developed for the simultaneous determination of ethyl glucuronide (EtG) and ethyl sulfate (EtS) in urine in negative ion conditions. Abundant [M-H] - species of EtG and EtS were obtained, allowing to reach limits of quantification (0.1 ?g\\/ml for both analytes), accuracy, and

Donata Favretto; Alessandro Nalesso; Giampietro Frison; Guido Viel; Pietro Traldi; Santo Davide Ferrara

2010-01-01

3

Determination of ethyl glucuronide in human hair by SPE and LC–MS\\/MS  

Microsoft Academic Search

A method for the sensitive and selective determination of ethyl glucuronide (EtG) in hair has been developed using solid-phase extraction (SPE) and liquid chromatography–tandem mass spectrometry (LC–MS\\/MS). Washed and cut hair segments were extracted by ultrasonication (3h, 50°C) and the extracts were cleaned-up with aminopropyl SPE columns. LC–MS\\/MS analysis was performed using a polar-endcapped phenyl-hexyl-RP-phase with negative mode electrospray ionisation

Ines Janda; Wolfgang Weinmann; Thorsten Kuehnle; Martina Lahode; Andreas Alt

2002-01-01

4

Ethyl glucuronide determination in meconium and hair by hydrophilic interaction liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

Ethyl glucuronide (EtG) detection in non-conventional matrices, such as hair and meconium, can provide useful information on alcohol abuse over a long time frame, for example during pregnancy or after a withdrawal treatment. This study reports on the development, validation and application of a new hydrophilic interaction liquid chromatography–tandem mass spectrometry (HILIC–MS\\/MS) method for the analysis of EtG in meconium

Isabela Tarcomnicu; Alexander L. N. van Nuijs; Katrien Aerts; Mireille De Doncker; Adrian Covaci; Hugo Neels

2010-01-01

5

Determination of ethyl glucuronide in hair samples by liquid chromatography/electrospray tandem mass spectrometry.  

PubMed

A method for the determination of ethyl glucuronide (EtG) in hair samples, using liquid chromatography/electrospray tandem mass spectrometry (LC/ESI-MS/MS), was developed and validated. The treatment of hair samples was as follows: to 100 mg of washed (dichloromethane followed by methanol, 1 ml each) and cut (1-2 mm) material, 700 microl of water, 20 microl of internal standard solution (pentadeuterated EtG, D(5)-EtG, 500 microg/l) and 20 microl of methanol were added. Samples were incubated at 25 degrees C overnight and then ultrasonicated for 2 h. Finally, 8 microl of the centrifuged solution (13,000 rpm) were analyzed by LC/ESI-MS/MS in negative ion mode. The surviving ions of EtG and D(5)-EtG were monitored together with the following MRM transitions: m/z 221 --> 75, m/z 221 --> 85 (EtG) and m/z 226 --> 75, m/z 226 --> 85 (D(5)-EtG). The method exhibited a mean correlation coefficient better than 0.9998 over the dynamic range (3-2000 pg/mg). The lower limit of quantification (LLOQ) and the limit of detection (LOD) were 3 and 2 pg/mg respectively. The intra- and interday precision and accuracy were studied at four different concentration levels (3, 5, 56 and 160 pg/mg) and were always better than 7% (n = 5). Matrix effects did not exceed 20%. The method was applied to several hair samples taken from autopsies of known alcoholics, from patients in withdrawal treatment, from social drinkers, from adult teetotalers and from children not exposed to ethanol, with EtG concentrations globally ranging from < or =2 to 4180 pg/mg. PMID:16287042

Morini, Luca; Politi, Lucia; Groppi, Angelo; Stramesi, Cristiana; Polettini, Aldo

2006-01-01

6

Determination of ethyl glucuronide in human hair by SPE and LC-MS/MS.  

PubMed

A method for the sensitive and selective determination of ethyl glucuronide (EtG) in hair has been developed using solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Washed and cut hair segments were extracted by ultrasonication (3h, 50 degrees C) and the extracts were cleaned-up with aminopropyl SPE columns. LC-MS/MS analysis was performed using a polar-endcapped phenyl-hexyl-RP-phase with negative mode electrospray ionisation (ESI) using a triple quadrupole mass spectrometer (Sciex API 365) with a turboionspray source and post-column addition of acetonitrile for enhanced sensitivity. The MS/MS transitions monitored were m/z 221 -->75 for EtG and 226 -->75 for D(5)-EtG as an internal standard. The method was selective and sensitive, with a detection limit of 51 pg/mg hair at a signal-to-noise ratio of 3:1. The mean recovery was 96%, with an intra- and inter-day precision of less than 11.7% at a concentration of 200 pg/mg. The linearity was assessed in the range of 25-2000 pg/mg hair, with a correlation coefficient of 0.997. The method was successfully applied to 97 human hair samples which were taken at autopsies from persons with known alcoholism or were obtained from alcoholics who were hospitalized for ethanol withdrawal, from social drinkers and from children having not consumed any alcohol. Although, approximately two-third of the alcoholics showed EtG concentrations in hair of higher than 51 pg/mg (up to >4000 pg/mg), in one-third the EtG concentration was below the detection limit. However, only in one of five hair samples of "social drinkers", the EtG concentration was above the detection limit (51 pg/mg). No EtG has been detected in the hair of children. These investigations demonstrate that heavy alcohol consumption may be but not necessarily has to be detectable by EtG analysis in hair. PMID:12208024

Janda, Ines; Weinmann, Wolfgang; Kuehnle, Thorsten; Lahode, Martina; Alt, Andreas

2002-08-14

7

Urinary concentrations of ethyl glucuronide and ethyl sulfate as thresholds to determine potential ethanol-induced alteration of steroid profiles.  

PubMed

The suppression of steroid biotransformation resulting in a decrease of the major urinary metabolites--androsterone and etiocholanolone--and the elevation of testosterone/epitestosterone (T/E) ratios following ethanol administration is well described. At least the latter parameter T/E represents an important indicator for endogenous steroid abuse in doping control. The quantitative correlation between ethanol consumption markers and steroid profile alteration was evaluated, aiming to differentiate between permitted ethanol administration and potential steroid abuse. Steroid profiles, ethanol, ethyl glucuronide (EtG), and sulfate (EtS) were quantified after administration of ethanol (intended maximum ethanol concentration in blood was 1 mg/g) to 21 male and 15 female volunteers. EtG concentrations in urine (corrected by either specific gravity or creatinine concentration) were found to be most suitable for quantitative evaluations. Gender specific urinary EtG concentrations of 48 ug/ml (men) and 15.5 ug/ml (women) may be considered as useful thresholds for a potential ethanol-induced suppression of steroids biotransformation. PMID:22213685

Thieme, D; Grosse, J; Keller, L; Graw, M

8

A fully validated high-performance liquid chromatography-tandem mass spectrometry method for the determination of ethyl glucuronide in hair for the proof of strict alcohol abstinence  

Microsoft Academic Search

Hair analysis has become a powerful tool for the detection of chronic and past drug consumption. For several years, it has\\u000a been possible to determine even the intake of ethanol in hair samples by detecting the ethanol metabolites ethyl glucuronide\\u000a or fatty acid ethyl esters. Recently, new requirements were published for the use of EtG as an abstinence test (c

Maria Elena Albermann; F. Musshoff; B. Madea

2010-01-01

9

Disappearance of ethyl glucuronide during heavy putrefaction  

Microsoft Academic Search

IntroductionThere are previous publications showing the use of ethyl glucuronide (EtG), a non-oxidative metabolite of ethanol, as a marker of ante-mortem ingestion of alcohol in forensic autopsy cases. The problem of possible degradation or formation of EtG during putrefaction is however not well studied and the aim of this study was to investigate the possibility of false negative and false

Gudrun Høiseth; Ritva Karinen; Lene Johnsen; Per Trygve Normann; Asbjørg S. Christophersen; Jørg Mørland

2008-01-01

10

A High-Performance Liquid Chromatographic-Tandem Mass Spectrometric Method for the Determination of Ethyl Glucuronide and Ethyl Sulfate in Urine Validated According to Forensic Guidelines  

PubMed Central

Ethyl glucuronide (EtG) and ethyl sulfate (EtS) are powerful markers for alcohol intake and abuse. Several analytical procedures for the quantification of EtG and EtG in serum and urine have been developed so far. Many of the published methods show limits of detections (LODs) or limits of quantifications (LOQs) for EtG in urine within the range of 0.1 mg/L or higher. Since this is the actual cutoff value for proving abstinence in Germany, problems may occur if urine samples are highly diluted. In this paper, the validation of a highly sensitive, fast and simple LC–MS–MS for the determination of EtG and EtS in urine is described. The calibration curves for EtG and EtS is linear over the whole range (0.025–2.0 mg/L). Very low detection limits can be achieved (LOD: EtG 0.005 mg/L, EtS 0.005 mg/L; and LOQ: EtG 0.019 mg/L, EtS 0.015 mg/L). All data for selectivity, precision and accuracy, recovery, as well as for the processed sample and the freeze/thaw stability, comply with the guidelines of the German Society of Toxicological and Forensic Chemistry. Strong matrix-related effects can be compensated for by using an internal standard. Finally, the applicability of the procedure is proven by analysis of 87 human urine samples and by successful participation in interlaboratory comparison tests.

Albermann, M.E.; Musshoff, F.; Madea, B.

2012-01-01

11

Detection of ethyl glucuronide in blood spotted on different surfaces  

Microsoft Academic Search

This study aims to show that sensitive detection of ethyl glucuronide in dried blood spotted onto various surfaces after a period of 24h is feasible. At present, there is insufficient information how tightly ethyl glucuronide (EtG) binds to various materials and how easily it can be eluted. 4ml aliquots of blood samples obtained from seven volunteers after consumption of alcoholic

M. Winkler; E. Kaufmann; D. Thoma; A. Thierauf; W. Weinmann; G. Skopp; A. Alt

2011-01-01

12

Microwave-assisted extraction: a simpler and faster method for the determination of ethyl glucuronide in hair by gas chromatography–mass spectrometry  

Microsoft Academic Search

Alcohol is the most frequently abused “addictive substance” that causes serious social problems throughout the world; thus,\\u000a alcoholism is of particular interest in clinical and forensic medicine. Alcohol biomarkers are physiological indicators of\\u000a alcohol exposure or ingestion and may reflect the presence of an alcohol use disorder. The glucuronide conjugation is a minor\\u000a pathway of ethanol metabolism. Ethyl glucuronide (EtG)

Iván Álvarez; Ana María Bermejo; María Jesús Tabernero; Purificación Fernández; Pamela Cabarcos; Patricia López

2009-01-01

13

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

PubMed

A commercial enzyme immunoassay for the qualitative and semi-quantitative measurement of ethyl glucuronide (EtG) in urine was evaluated. Post-mortem (n=800), and clinical urine (n=200) samples were assayed using a Hitachi 902 analyzer. The determined concentrations were compared with those obtained using a previously published liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of EtG and ethyl sulfate. Using a cut-off of 0.5?µg/ml and LC-MS/MS limit of reporting of 0.1?µg/ml, there was a sensitivity of 60.8% and a specificity of 100% for clinical samples. For post-mortem samples, sensitivity and specificity were 82.4% and 97.1%, respectively. When reducing the cut-off to 0.1?µg/ml, the sensitivity and specificity were 83.3% and 100% for clinical samples whereas for post-mortem samples the sensitivity and specificity were 90.3 % and 88.3 %, respectively. The best trade-offs between sensitivity and specificity for LC-MS/MS limits of reporting of 0.5 and 0.1?µg/ml were achieved when using immunoassay cut-offs of 0.3 and 0.092?µg/ml, respectively. There was good correlation between quantitative results obtained by both methods but analysis of samples by LC-MS/MS gave higher concentrations than by enzyme immunoassay (EIA), with a statistically significant proportional bias (P<0.0001, Deming regression) for both sample types. The immunoassay is reliable for the qualitative and semi-quantitative presumptive detection of ethyl glucuronide in urine. PMID:22374825

Turfus, Sophie C; Vo, Tu; Niehaus, Nadia; Gerostamoulos, Dimitri; Beyer, Jochen

2012-02-28

14

Validation of a headspace solid-phase microextraction–GC–MS\\/MS for the determination of ethyl glucuronide in hair according to forensic guidelines  

Microsoft Academic Search

The analysis of ethyl glucuronide (EtG) in hair is a powerful tool for chronic alcohol abuse control because of the typical wide detection window of the hair matrix and due to the possibility of segmentation, allowing evaluation of alcohol consumption in different periods. Additionally, EtG in hair is often the only diagnostic parameter of choice for alcohol abuse when other

Ronald Agius; Thomas Nadulski; Hans-Gerhard Kahl; Johannes Schräder; Bertin Dufaux; Michel Yegles; Fritz Pragst

2010-01-01

15

Comparison of ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEEs) concentrations in hair for testing abstinence  

Microsoft Academic Search

Hair analysis is a powerful tool for retrospective drug analysis. By determining the minor ethanol metabolites ethyl glucuronide\\u000a (EtG) and fatty acid ethyl esters (FAEEs) in hair, even a previous consumption of alcohol is detectable. However, previous\\u000a studies showed a lack of correlation if both parameters are determined simultaneously. A further study was conducted to confirm\\u000a or refute these results.

M. E. Albermann; F. Musshoff; B. Madea

2011-01-01

16

Investigations on the influence of different grinding procedures on measured ethyl glucuronide concentrations in hair determined with an optimized and validated LC-MS/MS method.  

PubMed

Ethyl glucuronide (EtG) analysis in hair is a suitable method for the retrospective determination of previous alcohol consumption. According to the German guidelines, EtG abstinence is improbable at c(EtG)?>?7 pg/mg in the proximal 3 cm of scalp hair. The chromatography of the routinely used liquid chromatography-tandem mass spectrometry procedure was optimized by replacing the stationary phase. To simplify sample preparation, two different mills were tested, and an optimized grinding process was developed. The new method was successfully validated according to the guidelines of the German Society of Toxicological and Forensic Chemistry. Despite a simple extraction procedure without any cleaning steps, a very high sensitivity (limit of detection, 1.7 pg/mg; limit of quantitation, 2.3 pg/mg) could be achieved. Competitive analysis showed significantly higher EtG concentrations in pulverized versus cut hair samples. The strong impact of sample preparation on the determined EtG concentrations suggests the introduction of a standardized sample preparation method to produce comparable results. PMID:22451175

Albermann, M E; Musshoff, F; Aengenheister, L; Madea, B

2012-03-27

17

Determination of ethyl-glucuronide in hair for heavy drinking detection using liquid chromatography-tandem mass spectrometry following solid-phase extraction.  

PubMed

The detection of ethyl-beta-D-6-glucuronide (EtG), a stable phase II metabolite of ethanol, is of interest in both clinical and forensic contexts with the aim of monitoring alcohol abuse. We present a liquid chromatography-electrospray ionisation-tandem mass spectrometry method for the detection and quantification of EtG in hair. Thirty milligrams of washed and cut hair were cleaned up using solid-phase extraction graphite cartridges. Separation was then performed using an Uptisphere-3SI column, and the detection was operated in the negative mode. After validation, the method was applied to hair samples taken from four fatalities (F) with documented excessive drinking habits, 12 heavy drinkers (HD) and seven social drinkers (SD). The method exhibits limits of detection and quantification of 4 and 10 pg/mg, respectively. Intra- and inter-assay standard deviation and relative bias were less than 20% over the calibrating range (10 to 3,000 pg/mg). EtG hair concentrations in SD were <10 pg/mg and >50 pg/mg for F and HD (range, 54 to 497 pg/mg). The present assay appears convenient to carry out owing to the very small quantity of hair samples required to determine an effective heavy alcohol consumption (EtG hair concentration >50 pg/mg). PMID:19517099

Lamoureux, Fabien; Gaulier, Jean-michel; Sauvage, François-Ludovic; Mercerolle, Magali; Vallejo, Christine; Lachâtre, Gérard

2009-06-12

18

Determination of ethyl-glucuronide in hair for heavy drinking detection using liquid chromatography-tandem mass spectrometry following solid-phase extraction  

Microsoft Academic Search

The detection of ethyl-?-d-6-glucuronide (EtG), a stable phase II metabolite of ethanol, is of interest in both clinical and forensic contexts with\\u000a the aim of monitoring alcohol abuse. We present a liquid chromatography-electrospray ionisation-tandem mass spectrometry method\\u000a for the detection and quantification of EtG in hair. Thirty milligrams of washed and cut hair were cleaned up using solid-phase\\u000a extraction graphite

Fabien Lamoureux; Jean-michel Gaulier; François-Ludovic Sauvage; Magali Mercerolle; Christine Vallejo; Gérard Lachâtre

2009-01-01

19

Blood kinetics of ethyl glucuronide and ethyl sulphate in heavy drinkers during alcohol detoxification  

Microsoft Academic Search

Studies of ethyl glucuronide (EtG) blood kinetics have so far been performed on healthy volunteers with ingestion of low to moderate doses of ethanol. These data are not necessarily transferable to heavy drinkers where the consumed doses of ethanol are much higher. The aim of this study was to investigate the pharmacokinetics of EtG and ethyl sulphate (EtS) in blood

Gudrun Høiseth; Luca Morini; Aldo Polettini; Asbjørg Christophersen; Jørg Mørland

2009-01-01

20

In vitro study of bacterial degradation of ethyl glucuronide and ethyl sulphate  

Microsoft Academic Search

Recent studies show that ethyl glucuronide (EtG) can be decomposed by bacteria; whilst so far no degradation of ethyl sulphate\\u000a (EtS) has been observed. In the present study, in vitro experiments with bacterial colonies were performed. Bacteria (Escherichia coli, Klebsiella pneumoniae, Clostridium sordellii) were isolated from autopsy material (liver, heart blood, urine, ascites, pericardial fluid, pleural fluid) tested for ?-glucuronidase

Stefanie Baranowski; Annerose Serr; Annette Thierauf; Wolfgang Weinmann; Markus Gro?e Perdekamp; Friedrich M. Wurst; Claudia C. Halter

2008-01-01

21

Abstinence Monitoring of Suspected Drinking Drivers: Ethyl Glucuronide in Hair Versus CDT  

Microsoft Academic Search

Objective: Ethyl glucuronide (EtG) determinations in the hair of self-reported teetotalers were reviewed and compared with carbohydrate-deficient transferrin (CDT) blood tests (by immunochemistry and high-performance liquid chromatography [HPLC]).Methods: A retrospective study was carried out on 154 people whose fitness to drive had to be assessed because of the suspicion of relevant alcohol problems.Results: EtG was detected in 55 percent of

Bruno Liniger; Ariane Nguyen; Andrea Friedrich-Koch; Michel Yegles

2010-01-01

22

Determination of ethyl glucuronide in nails by liquid chromatography tandem mass spectrometry as a potential new biomarker for chronic alcohol abuse and binge drinking behavior.  

PubMed

A liquid chromatography tandem mass spectrometry method for ethyl glucuronide (EtG) detection and quantification in nails was developed and fully validated. Nails were extracted in 700 ?L double-distilled water. EtG-d(5) was used as an internal standard. Reversed-phase separation was obtained with an isocratic mobile phase composed of 0.1% formic acid and acetonitrile (99:1) for 10 min. Quantification was performed by multiple reaction monitoring of two transitions per compound (EtG and internal standard). The assay was linear from 10 to 500 pg/mg. Validation parameters were studied at three different quality control levels (10, 50, and 300 pg/mg). Intraday, interday, and total imprecision had a coefficient of variation of less than 9.5%. Ion suppression and ion enhancement were negligible (less than 20%). No carryover was detected. The method was applied to several real cases, among teetotalers, social drinkers, and heavy drinkers. A questionnaire, together with the informed consent form, was given to all the participants in order to evaluate alcohol intake in the one month before sample collection. Nail EtG levels in a social drinker were much higher than the concentrations of EtG in hair provided by the same subject, thus suggesting potential high sensitivity in evaluating both chronic excessive alcohol consumption and binge drinking habits. PMID:22193819

Morini, Luca; Colucci, Mario; Ruberto, Maria Giovanna; Groppi, Angelo

2011-12-23

23

Development and validation of a gas chromatography–negative chemical ionization tandem mass spectrometry method for the determination of ethyl glucuronide in hair and its application to forensic toxicology  

Microsoft Academic Search

Ethyl glucuronide (EtG) is a minor and direct metabolite of ethanol. EtG is incorporated into the growing hair allowing retrospective investigation of chronic alcohol abuse. In this study, we report the development and the validation of a method using gas chromatography–negative chemical ionization tandem mass spectrometry (GC–NCI-MS\\/MS) for the quantification of EtG in hair. EtG was extracted from about 30mg

Hicham Kharbouche; Frank Sporkert; Stéphanie Troxler; Marc Augsburger; Patrice Mangin; Christian Staub

2009-01-01

24

Urine tested positive for ethyl glucuronide and ethyl sulphate after the consumption of “non-alcoholic” beer  

Microsoft Academic Search

In abstinence maintenance programs, for reissuing the driving licence and in workplace monitoring programs abstinence from ethanol and its proof are demanded. Various monitoring programs that mainly use ethyl glucuronide (EtG) as alcohol consumption marker have been established. To abstain from ethanol, but not from the taste of alcoholic beverages, in particular non-alcoholic beer has become more and more popular.

Annette Thierauf; Heike Gnann; Ariane Wohlfarth; Volker Auwärter; Markus Große Perdekamp; Klaus-Juergen Buttler; Friedrich M. Wurst; Wolfgang Weinmann

2010-01-01

25

Assessment of UDP-glucuronosyltransferase catalyzed formation of ethyl glucuronide in human liver microsomes and recombinant UGTs  

Microsoft Academic Search

While ethanol is primarily metabolized to acetaldehyde and acetic acid via alcohol dehydrogenase, a minor but increasingly important pathway in the field of forensic science involves the conjugation of glucuronic acid to form an ethyl glucuronide (EtG) metabolite. The kinetics of ethyl glucuronide formation were examined in human liver microsomes (HLM) and recombinant UDP-glucuronosyltransferases (UGTs). The metabolite exhibited a relatively

Robert S. Foti; Michael B. Fisher

2005-01-01

26

Distribution of ethyl glucuronide in rib bone marrow, other tissues and body liquids as proof of alcohol consumption before death  

Microsoft Academic Search

Postmortem ethyl glucuronide (EtG) concentrations in rib bone marrow, liver, muscle, fat tissue, urine, blood and bile have been determined by LC–MS\\/MS. Samples have been taken from twelve corpses during autopsies. In nine corpses EtG could be detected, corresponding blood ethanol concentrations (BAC) were 0.04–0.37g%. In three cases, no EtG was found; two of these cases showed postmortem BACs –

Haiko Schloegl; Thomas Rost; Wolfgang Schmidt; Friedrich Martin Wurst; Wolfgang Weinmann

2006-01-01

27

Ethyl glucuronide and ethyl sulfate in autopsy samples 27 years after death.  

PubMed

The unique case of a 50-year-old known alcoholic whose corpse was exhumed 27 years after death is reported. The man apparently committed suicide by hanging, but many years later the case was questioned and homicide-linked to a long-lasting serial killer case-was suspected. Thus, the corpse was exhumed, and at the autopsy it was found to be naturally mummified. This fact permitted the analysis of body tissues with the aim to investigate the persistence of ethanol conjugates in the biological material 27 years after death. Fragments of liver and kidney, a blood clot, and a hair strand were collected and submitted to liquid chromatography tandem mass spectrometry analysis. Ethyl glucuronide (EtG) and ethyl sulfate (EtS) were identified and quantified in the liver, the kidney, and the blood clot. Hair analysis was found to be severely affected by ion suppression even after solid phase extraction. Consequently, EtG was identified in all hair segments (0-3 cm, 3-6 cm, and 6-10 cm), but no reliable quantification could be carried out. In summary, our findings demonstrate that, notwithstanding the expected conjugate degradation, EtG and EtS can be indicative of ante-mortem use of alcohol even many years after death. PMID:18661140

Politi, Lucia; Morini, Luca; Mari, Francesco; Groppi, Angelo; Bertol, Elisabetta

2008-07-26

28

The influence of ethanol containing cosmetics on ethyl glucuronide concentration in hair  

Microsoft Academic Search

Ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEE), non-volatile, direct metabolites of ethanol have been shown to be suitable markers for the evaluation of social and chronic excessive alcohol consumption. Previous investigations have shown that the regular use of hair-care products with high alcohol content lead to an increase of FAEE concentration and consequently gave false-positive results for the

Liliane Martins Ferreira; Tina Binz; Michel Yegles

29

Ethyl glucuronide: on the time course of excretion in urine during detoxification  

Microsoft Academic Search

Ethyl glucuronide (EtG) is a promising new biological state marker of recent alcohol consumption that detects alcohol use reliably over a definite time period. Other currently available markers lack acceptable sensitivity and specificity. Our aim is to elucidate under naturalistic conditions the time course of EtG excretion in urine following alcohol consumption and to show how this can be utilized

Friedrich Martin Wurst; Stephan Seidl; Dieter Ladewig; Franz Müller-Spahn; Andreas Alt

2002-01-01

30

Voucher-Based Reinforcement for Alcohol Abstinence Using the Ethyl-Glucuronide Alcohol Biomarker  

ERIC Educational Resources Information Center

|This study assessed the effects of a contingency management (CM) intervention for alcohol consumption in 10 alcohol-dependent participants. An ABCA design was used. Vouchers were provided contingent on results of ethyl glucuronide (EtG) urine tests (an alcohol biomarker with a 2-day detection period) and alcohol breath tests during the C phase.…

McDonell, Michael G.; Howell, Donelle N,; McPherson, Sterling; Cameron, Jennifer M.; Srebnik, Debra; Roll, John M.; Ries, Richard K.

2012-01-01

31

Development and validation of a gas chromatography-negative chemical ionization tandem mass spectrometry method for the determination of ethyl glucuronide in hair and its application to forensic toxicology.  

PubMed

Ethyl glucuronide (EtG) is a minor and direct metabolite of ethanol. EtG is incorporated into the growing hair allowing retrospective investigation of chronic alcohol abuse. In this study, we report the development and the validation of a method using gas chromatography-negative chemical ionization tandem mass spectrometry (GC-NCI-MS/MS) for the quantification of EtG in hair. EtG was extracted from about 30 mg of hair by aqueous incubation and purified by solid-phase extraction (SPE) using mixed mode extraction cartridges followed by derivation with perfluoropentanoic anhydride (PFPA). The analysis was performed in the selected reaction monitoring (SRM) mode using the transitions m/z 347-->163 (for the quantification) and m/z 347-->119 (for the identification) for EtG, and m/z 352-->163 for EtG-d(5) used as internal standard. For validation, we prepared quality controls (QC) using hair samples taken post mortem from 2 subjects with a known history of alcoholism. These samples were confirmed by a proficiency test with 7 participating laboratories. The assay linearity of EtG was confirmed over the range from 8.4 to 259.4 pg/mg hair, with a coefficient of determination (r(2)) above 0.999. The limit of detection (LOD) was estimated with 3.0 pg/mg. The lower limit of quantification (LLOQ) of the method was fixed at 8.4 pg/mg. Repeatability and intermediate precision (relative standard deviation, RSD%), tested at 4 QC levels, were less than 13.2%. The analytical method was applied to several hair samples obtained from autopsy cases with a history of alcoholism and/or lesions caused by alcohol. EtG concentrations in hair ranged from 60 to 820 pg/mg hair. PMID:19109074

Kharbouche, Hicham; Sporkert, Frank; Troxler, Stéphanie; Augsburger, Marc; Mangin, Patrice; Staub, Christian

2008-12-06

32

An improved method to detect ethyl glucuronide in urine using reversed-phase liquid chromatography and pulsed electrochemical detection.  

PubMed

Pulsed electrochemical detection (PED) following reversed-phase liquid chromatography (LC) has been applied recently to the detection of ethyl glucuronide (EtG) in the urine of live and deceased individuals. In this paper, several key improvements to the method are made to enhance sensitivity, reproducibility, and accuracy. These improvements include (i) further optimization of the sample preparation procedure that has increased the recovery from ca. 50% to 84+/-3% in synthetic urine matrix; (ii) changing the internal standard from methyl glucuronide (MetG) to propyl glucuronide (ProG), which does not elute within the interference of the matrix; and (iii) altering the mobile phase of the separation from acetonitrile to t-butanol to virtually eliminate signal suppression in PED. As a consequence, detection limits have been reduced to 0.01 microg mL(-1), reproducibility has been improved by a factor of two, and sample size has been reduced five-fold. Blind studies in synthetic urine showed no significant difference between the amount recovered and the true value determined at the 95% confidence level for all samples. Importantly, PED requires no derivatization, and it can detect virtually all glucuronides. PMID:17723638

Shah, Romina; Lacourse, William R

2006-06-16

33

Blood kinetics of ethyl glucuronide and ethyl sulphate in heavy drinkers during alcohol detoxification.  

PubMed

Studies of ethyl glucuronide (EtG) blood kinetics have so far been performed on healthy volunteers with ingestion of low to moderate doses of ethanol. These data are not necessarily transferable to heavy drinkers where the consumed doses of ethanol are much higher. The aim of this study was to investigate the pharmacokinetics of EtG and ethyl sulphate (EtS) in blood in heavy drinkers after termination of alcohol ingestion. Sixteen patients from an alcohol withdrawal clinic were included directly after admission. Time of end of drinking, estimated daily intake of ethanol (EDI) and medical history were recorded. Three to five blood samples over 20-43 h were collected from each patient subsequent to admission. The median EDI was 172 g (range 60-564). The first sample was collected median 2.5 h after end of drinking (range 0.5-23.5). Two patients had levels of EtG and EtS below LOQ in all samples, the first collected 19.25 and 23.5 h after cessation of drinking, respectively. Of the remaining 14 patients, one subject, suffering from both renal and hepatic disease, showed concentrations of EtG and EtS substantially higher than the rest of the material. This patient's initial value of EtG was 17.9 mg/L and of EtS 5.9 mg/L, with terminal elimination half lives of 11.9 h for EtG and 12.5 h for EtS. Among the remaining 13 patients, the initial median values were 0.7 g/L (range 0-3.7) for ethanol, 1.7 mg/L (range 0.1-5.9) for EtG and 0.9 mg/L (range 0.1-1.9) for EtS. Elimination occurred with a median half-life of 3.3 h for EtG (range 2.6-4.3) and 3.6 h for EtS (range 2.7-5.4). In conclusion, elimination of EtG in heavy drinkers did not significantly differ from healthy volunteers, and EtS appeared to have similar elimination rate. In the present work, there was one exception to this, and we propose that this could be explained by the patient's renal disease, which would delay excretion of these conjugated metabolites. PMID:19395207

Høiseth, Gudrun; Morini, Luca; Polettini, Aldo; Christophersen, Asbjørg; Mørland, Jørg

2009-04-23

34

ETHYL GLUCURONIDE — A MARKER OF ALCOHOL CONSUMPTION AND A RELAPSE MARKER WITH CLINICAL AND FORENSIC IMPLICATIONS  

Microsoft Academic Search

Ethyl glucuronide (EtG) is a non-volatile, water-soluble, direct metabolite of ethanol that can be detected in body fluids and hair. We investigated urine and serum samples from three patient groups: (1) 33 in-patients in acute alcohol withdrawal; (2) 30 detoxified in-patients (treated for at least 4 weeks) from a 'motivation station'; and (3) 43 neuro-rehabilitation patients (non-alcoholics; most of them

FRIEDRICH MARTIN WURST; CHRISTOPH KEMPTER; STEPHAN SEIDL; ANDREAS ALT

35

Voucher-based reinforcement for alcohol abstinence using the ethyl-glucuronide alcohol biomarker.  

PubMed

This study assessed the effects of a contingency management (CM) intervention for alcohol consumption in 10 alcohol-dependent participants. An ABCA design was used. Vouchers were provided contingent on results of ethyl glucuronide (EtG) urine tests (an alcohol biomarker with a 2-day detection period) and alcohol breath tests during the C phase. The percentage of negative urines was 35% during the first baseline phase, 69% during the C phase, and 20% during the return-to-baseline phase. Results suggest that EtG urine tests may be a feasible method to deliver CM to promote alcohol abstinence. PMID:22403460

McDonell, Michael G; Howell, Donelle N; McPherson, Sterling; Cameron, Jennifer M; Srebnik, Debra; Roll, John M; Ries, Richard K

2012-01-01

36

Stability of ethyl glucuronide in urine, post-mortem tissue and blood samples  

Microsoft Academic Search

The stability of ethyl glucuronide (EtG) under conditions of degradation was examined in urine samples of nine volunteers\\u000a and in post-mortem tissue (liver, skeletal muscle) and blood taken from seven corpses at autopsies. Analysis was performed\\u000a via LC-MS\\/MS. EtG concentrations in urine samples ranged from 2.5 to 296.5 mg\\/l. When stored at 4°C in airtight test tubes,\\u000a EtG concentrations remained relatively

Haiko Schloegl; Sebastian Dresen; Karin Spaczynski; Mylène Stoertzel; Friedrich Martin Wurst; Wolfgang Weinmann

2006-01-01

37

VOUCHER-BASED REINFORCEMENT FOR ALCOHOL ABSTINENCE USING THE ETHYL-GLUCURONIDE ALCOHOL BIOMARKER  

PubMed Central

This study assessed the effects of a contingency management (CM) intervention for alcohol consumption in 10 alcohol-dependent participants. An ABCA design was used. Vouchers were provided contingent on results of ethyl glucuronide (EtG) urine tests (an alcohol biomarker with a 2-day detection period) and alcohol breath tests during the C phase. The percentage of negative urines was 35% during the first baseline phase, 69% during the C phase, and 20% during the return-to-baseline phase. Results suggest that EtG urine tests may be a feasible method to deliver CM to promote alcohol abstinence.

McDonell, Michael G; Howell, Donelle N; McPherson, Sterling; Cameron, Jennifer M; Srebnik, Debra; Roll, John M; Ries, Richard K

2012-01-01

38

Immunoassay for ethyl glucuronide in vitreous humor: a new tool for postmortem diagnostics of alcohol use.  

PubMed

Although excessive alcohol consumption plays a major role in fatal events, the role of alcohol use as a possible contributing factor at the time of death is not easy to establish due to lack of suitable biomarkers for postmortem analyses. We used an immunological approach to measure ethyl glucuronide (EtG) concentrations from vitreous humor (VH) and serum from 58 individuals representing a forensic autopsy population of cases with either a well-documented history of excessive alcohol use (n=37) or cases without such history (n=21), according to medical and police records and blood alcohol determinations (BAC). The immunoassay was based on the Microgenics DRI-EtG EIA reagents applied on an automated Abbott Architect c8000 clinical chemistry analyzer. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) determination of EtG and ethyl sulfate (EtS) was used as a reference method. At a cut-off of 0.3mg/l for VH-EtG, the immunoassay correctly identified 92% of the cases with a history of excessive alcohol use, whereas the BAC was positive (cut-off 10mg/dl) in 68% of the cases. A significant correlation emerged between VH-EtG and serum EtG (r=0.77, p<0.001) and between VH-EtG and BAC (r=0.62, p<0.001), although VH-EtG was frequently elevated also in cases with no detectable BAC. The EtG immunoassay showed a strong correlation with the LC-MS/MS reference method (r=0.94, p<0.001) and there was 100% agreement in the frequency of marker positive and negative findings between the immunoassay EtG results and the LC-MS/MS analysis of EtG and EtS. The present data indicate that the immunoassay for VH-EtG is a useful forensic tool for screening of antemortem alcohol use. PMID:23415594

Rainio, Juha; Kultti, Johanna; Kangastupa, Päivikki; Tuomi, Heidi; Ahola, Sanna; Karhunen, Pekka J; Helander, Anders; Niemelä, Onni

2013-02-13

39

Ethyl glucuronide, ethyl sulfate, and ethanol in urine after sustained exposure to an ethanol-based hand sanitizer.  

PubMed

To assess the degree of ethanol absorption and subsequent formation of urinary ethyl glucuronide (EtG) and ethyl sulfate (EtS) following sustained application of hand sanitizer, 11 volunteers cleansed their hands with Purell(™) hand sanitizer (62% ethanol) every 5 min for 10 h on three consecutive days. Urine specimens were obtained at the beginning and end of each day of the study, and on the morning of the fourth day. Urinary creatinine, ethanol, EtG, and EtS concentrations were measured. EtG was undetectable in all pre-study urine specimens, but two pre-study specimens had detectable EtS (73 and 37 ng/mL). None of the pre-study specimens had detectable ethanol. The maximum EtG and EtS concentrations over the course of the study were 2001 and 84 ng/mL, respectively, and nearly all EtG- and EtS-positive urine specimens were collected at the conclusion of the individual study days. Only two specimens had detectable EtG at the beginning of any study day (96 and 139 ng/mL), and only one specimen had detectable EtS at the beginning of a study day (64 ng/mL), in addition to the two with detectable EtS prior to the study. Creatinine-adjusted maximum EtG and EtS concentrations were 1998 and 94 ?g/g creatinine, respectively. In patients being monitored for ethanol use by urinary EtG concentrations, currently accepted EtG cutoffs do not distinguish between ethanol consumption and incidental exposures, particularly when urine specimens are obtained shortly after sustained use of ethanolcontaining hand sanitizer. Our data suggest that EtS may be an important complementary biomarker in distinguishing ethanol consumption from dermal exposure. PMID:21396227

Reisfield, Gary M; Goldberger, Bruce A; Crews, Bridgit O; Pesce, Amadeo J; Wilson, George R; Teitelbaum, Scott A; Bertholf, Roger L

2011-03-01

40

Comparison of ethyl glucuronide in hair with phosphatidylethanol in whole blood as post-mortem markers of alcohol abuse  

Microsoft Academic Search

Ethyl glucuronide (EtG) is a direct metabolite of ethanol and has been used as a marker of alcohol abuse in both urine and hair. This study investigated the value of EtG testing in post-mortem hair for diagnostic improvement of alcohol abuse in forensic medicine. Material from 70 consecutive medico-legal autopsies was collected in accordance with the recommendations on ethics by

Peter Bendroth; Robert Kronstrand; Anders Helander; Jesper Greby; Nikolai Stephanson; Peter Krantz

2008-01-01

41

Ethyl glucuronide excretion in humans following oral administration of and dermal exposure to ethanol.  

PubMed

Ethyl glucuronide (EtG) is a direct ethanol biomarker and U.S. Department of Health and Human Services has advised that specificity studies at low EtG levels are needed for distinction of ethanol consumption and incidental exposure. The authors report urinary EtG excretion with ethanol abstinence, dermal exposure and oral consumption. EtG concentration by sensitive liquid chromatography-tandem mass spectrometry measurement in 39 urine specimens from adult alcohol abstainers (< 10-62 microg/L) and in urine from 13 children (< 10-80 microg/L) indicates either unrecognized ethanol exposure or endogenous ethanol metabolism. With repetitive daily dermal exposure to hand sanitizer (60% ethanol) by 9 adults, EtG concentration ranged from < 10 to 114 microg/L in 88 first-morning void specimens. EtG excretion following a 24 g ethanol drink by 4 adults revealed maximum urine EtG concentration (12,200-83,200 microg/L) at 3 to 8 h postdose and an EtG detection window up to 25-39 h, compared to an ethanol window of only 2 to 4 h. Oral ethanol use also showed an increase in the percent (molar equivalent) ethanol excreted as EtG with increasing oral ethanol doses. Human excretion studies show 1. EtG detectable at low concentration (< 100 microg/L) when ethanol use or exposures is not evident, 2. EtG concentration less than 120 microg/L in first morning specimens from adults with repeated dermal exposure to ethanol, 3. EtG levels maximally elevated within 3-8 h and above baseline for up to 39 h after a 24 g ethanol drink, and 4. a dose-dependent increase in the percentage of ethanol excreted as EtG with increasing oral ethanol use. PMID:19007508

Rosano, Thomas G; Lin, Jing

2008-10-01

42

Diagnosis of chronic alcohol consumption. Hair analysis for ethyl-glucuronide.  

PubMed

This paper describes a procedure for the detection and quantification of ethyl-glucuronide (EtG) in hair samples. During method development the efficacy of extraction of EtG from hair was compared in four extraction methods: (a) methanol; (b) methanol:water (1:1); (c) water; and (d) water:trifluoroacetic acid (9:1). In addition, three derivatizing agents were compared as well: N,O-bistrimethylsilyl-trifluoroacetamide (BSTFA): trimethylchlorosilane (TMCS) (99:1), pentafluoropropionic anhydride (PFPA) and heptafluorobutyric anhydride (HFBA). Water was found to be the best extracting solvent and PFPA the best derivatizing agent. Both provided the highest recoveries, with cleaner extracts and more stable derivatives. The final method is as follows: about 100mg of hair are sequentially washed with water and acetone. The decontaminated sample is finely cut with scissors, then the deuterated internal standard (EtG-d5) and 2 mL of water are added. After sonication for 2 h, the sample is maintained at room temperature overnight. Derivatization is performed with PFPA. Derivatives are injected into a GC-MS system in the electronic impact mode. The method shows linearity over the range of concentrations from 0.050 to 5 ng/mg. Detection and quantification limits are 0.025 and 0.050 ng/mg, respectively. Mean recoveries for the three studied concentrations (low, medium and high) are higher than 87%. The coefficients of variation in intra- and inter-assay precision are always lower than 7%. The method is being routinely applied in our lab for the diagnosis of chronic alcohol consumption. PMID:15451088

Jurado, C; Soriano, T; Giménez, M P; Menéndez, M

2004-10-29

43

A specific immunoassay for the determination of morphine and its glucuronides in human blood  

Microsoft Academic Search

The development of specific antisera for immunochemical determination of morphine, morphine-3-glucuronide and morphine-6-glucuronide\\u000a is described. Morphine was N-demethylated to normorphine and N-alkylated to give N-aminopropyl-normorphine as hapten for antisera\\u000a against morphine. As haptens for antisera against morphine-3-glucuronide and morphine-6-glucuronide, N-aminopropyl-nor-morphine\\u000a was glucuronidated in position 3 or 6 respectively. Each of these three haptens were coupled to BSA employing the glutaraldehyde

J. Beike; G. Blaschke; A. Mertz; H. Köhler; B. Brinkmann

1998-01-01

44

Preliminary investigations on ethyl glucuronide and ethyl sulfate cutoffs for detecting alcohol consumption on the basis of an ingestion experiment and on data from withdrawal treatment.  

PubMed

Ethyl glucuronide (EtG) and ethyl sulfate (EtS) are commonly used alcohol markers for previous alcohol consumption. Nevertheless, the optimum EtG cutoff for urinary abstinence tests is still being discussed, and no cutoff has been recommended for EtS yet. The aim of this study was to verify cutoffs by investigating EtG and EtS concentrations (c(EtG) and c(EtS)) in the urine of healthy persons after drinking small, but realistic amounts of alcohol (one or two glasses of beer or white wine), and to look for the window of detection in strongly alcohol-intoxicated patients who were beginning withdrawal treatment. Very high EtG and EtS concentrations were measured in the first urine samples of patients under withdrawal treatment. However, 24 h later, concentrations decreased considerably, and c (EtG)?determined in 26.7 % (4/13) and 13.3 % (2/13) of the samples, respectively. Concentrations above 0.1 mg/l (EtG) and 0.05 mg/l (EtS) were measured for 23.5 and 20.5 h after consuming 0.1 l of white wine or 0.33 l of beer, and 24 h after the experiment, 75 % (9/12) of the urine samples were tested negative for EtG and EtS using the following cutoffs: EtG 0.5 mg/l and EtS 0.1 mg/l. In half of the samples, concentrations below 0.1 mg/l (EtG) and 0.05 mg/l (EtS) were detected. Urinary cutoffs for EtG of 0.5 mg/l or higher are not suitable for testing abstinence. Even 0.1 mg/l is not effective to detect the intake of small amounts of alcohol in the context of abstinence tests. For EtS, 0.05 mg/l were found to be a potential cutoff to exclude the repeated intake of alcohol. Yet, further research is required to verify this cutoff. For a limited time period, EtG and EtS concentrations within the range of these cutoffs are also detectable after unintentional consumption of alcohol. Participants of abstinence programs have to be informed about the alcohol content of certain foods and beverages whose consumption is in conflict with strict abstinence. PMID:22752748

Albermann, Maria Elena; Musshoff, Frank; Doberentz, Elke; Heese, Peter; Banger, Markus; Madea, Burkhard

2012-06-30

45

Determination of raloxifene and its glucuronides in human urine by liquid chromatography–tandem mass spectrometry assay  

Microsoft Academic Search

A selective, sensitive, accurate and precise liquid chromatography–tandem mass spectrometry (LC–MS\\/MS) method for determination of raloxifene and its three glucuronides: raloxifene-6-?-glucuronide (M1), raloxifene-4?-?-glucuronide (M2), raloxifene-6,4?-diglucuronide (M3) in urine samples is presented in this paper. To our knowledge the developed analytical method is the first fully validated method capable of simultaneous determination of raloxifene and its glucuronides in real urine samples.

Tina Trdan; Robert Roškar; Jurij Trontelj; Matjaž Ravnikar; Aleš Mrhar

2011-01-01

46

Detecting alcohol abuse: traditional blood alcohol markers compared to ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEEs) measurement in hair.  

PubMed

Alcohol abuse is a common problem in society; however, the technical capabilities of evaluating individual alcohol consumption using objective biomarkers are rather limited at present. In recent years research has focused on alcohol markers using hair analysis but data on performance and reliable cut-off values are still lacking. In this study 169 candidates were tested to compare traditional biomarkers, such as carbohydrate-deficient-transferrin (CDT), gamma glutamyl transferase (GGT), aspartate amino transferase, alanine amino transferase and the mean corpuscular volume of the erythrocytes, with alcohol markers detectable in hair such as ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEEs). This study revealed that EtG, GGT and CDT showed the best results, demonstrating areas under the curve calculated from receiver operating characteristics of 0.941, 0.943 and 0.899 respectively. The lowest false-negative and false-positive rates were obtained by using a combined interpretation system for hair EtG and FAEEs. All markers demonstrated only low to moderate correlations. Optimum cut-off values for differentiation between social and chronic excessive drinking calculated for hair EtG and FAEEs were 28 pg/mg and 0.675 ng/mg, respectively. The critical values published in the "Consensus on Alcohol Markers 2012" by the Society of Hair Testing were confirmed. PMID:23504201

Hastedt, Martin; Büchner, Mara; Rothe, Michael; Gapert, René; Herre, Sieglinde; Krumbiegel, Franziska; Tsokos, Michael; Kienast, Thorsten; Heinz, Andreas; Hartwig, Sven

2013-03-17

47

Determination of Kow Values for a Series of Aryl Glucuronides  

Microsoft Academic Search

Polynuclear aromatic hydrocarbons (PAHs) are a class of hazardous contaminants in the aquatic environment that readily accumulate in animals. We have recently become interested in understanding the formation, distribution, and elimination of phase II metabolites of PAHs in fish (McKim et al. 1993) in support of the U.S. EPA’s hazardous chemical risk assessment programs. Glucuronides are one of the important

D. W. Kuehl; J. Christensen

1999-01-01

48

Practical experiences in application of hair fatty acid ethyl esters and ethyl glucuronide for detection of chronic alcohol abuse in forensic cases.  

PubMed

This article presents results from 1872 hair samples, which were analyzed for fatty acid ethyl esters (FAEEs) and ethyl glucuronide (EtG). The results were evaluated in the context of self-reported drinking behavior, the use of hair cosmetics, the gender of the sample donors and hair sample length. For comparison, CDT and GGT in serum were available in 477 and 454 cases, respectively. A number of alcohol abstainers or low moderate drinkers and excessive drinkers were selected for assessment of cut-offs for FAEEs in the proximal 6cm hair segments and for EtG in the proximal 3cm hair segments. Cut-off values were assessed by ROC analysis. It was found that the cut-offs of 1.0ng/mg FAEE and 30pg/mg EtG presently used for excessive drinking lead to a low portion of false positives (4% and 3% respectively) but to a higher portion of false negatives (23% and 25% respectively). Comparison of the mean and medium concentrations in samples without any reported hair cosmetics (N=1079) and in samples with reported use of hair spray (N=79) showed an increase by the factor of about two for FAEE but no significant difference for EtG. Mean values of EtG were decreased by 80% in bleached samples (N=164) and by 63% in dyed samples (N=96). There was no significant effect of bleaching and dyeing on FAEE. Hair gel and hair wax, oil or grease showed no significant effect on both FAEE and EtG. With respect to gender and investigated hair length ambiguous results were obtained because of major differences in the compared subpopulations of male with higher alcohol consumption and mainly shorter hair, and less drinking female with longer hair. For excessive drinkers FAEEs in the 0-6cm hair segment and EtG in the 0-3cm segment decreased with increasing time of reported abstinence before sample collection. These drinkers attain the level of teetotalers only after more than 10 months of abstinence. In comparison to scalp hair, FAEEs recovered from armpit hair and leg hair were lower and from chest hair were higher. EtG in armpit hair was lower and in leg hair higher than in scalp hair. It is concluded that the combined use of FAEE and EtG essentially increases the accuracy of interpretation since both markers complement each other by a different sensitivity to sources of error. PMID:22036309

Suesse, S; Pragst, F; Mieczkowski, T; Selavka, C M; Elian, A; Sachs, H; Hastedt, M; Rothe, M; Campbell, J

2011-10-27

49

Analysis of ethyl glucuronide in hair samples by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS).  

PubMed

Many different biomarkers can be used to evaluate ethanol intake. Ethyl glucuronide (EtG) is a direct phase II and minor metabolite of ethanol formed through the UDP-glucuronosyl transferase-catalyzed conjugation of ethanol with glucuronic acid. Its investigation is of interest in both clinical and forensic contexts because of the wide window of detection. A sensitive LC-MS/MS procedure has been developed and fully validated according to the guidelines of forensic toxicology for the analysis of EtG in hair. Sample preparation and chromatographic separation were thoroughly optimized. The analysis was performed in the multiple reaction monitoring mode using the transitions m/z 221 ? 203 (for the quantification) and 221 ? 85 or 75 (for the qualification) for EtG, and m/z 226 ? 208 (for quantification) and 226 ? 75 or 85 (for qualification) for EtG-D5, used as the internal standard. Analyses were carried out using an Inertsil ODS-3 column (100 × 3 mm i.d., 3 µm particle size) and a mobile phase composed of formic acid and acetonitrile. Various SPE cartridges and solvents were tested in order to obtain the highest recoveries and cleanest extracts. The assay linearity of EtG was confirmed over the range from 20 to 2500 pg mg(-1), with a coefficient of determination (R(2) ) above 0.99. The lower limit of quantitation (LLOQ) was 20 pg mg(-1) and the limit of detection was 10 pg mg(-1). Intra- and inter-day assays were less than 15% except at the LLOQ (20%). The analytical method was applied to 72 post-mortem hair samples. EtG concentration in the hair ranged from 0 to 653 pg mg(-1) hair. PMID:22234871

Cabarcos, Pamela; Hassan, Huda M; Tabernero, María Jesús; Scott, Karen S

2012-01-10

50

Profiling serum bile Acid glucuronides in humans: gender divergences, genetic determinants, and response to fenofibrate.  

PubMed

Glucuronidation, catalyzed by uridine 5'-diphospho-glucuronosyltransferase (UGT) enzymes, detoxifies cholestatic bile acids (BAs). We aimed to (i) characterize the circulating BA-glucuronide (BA-G) pool composition in humans, (ii) determine how sex and UGT polymorphisms influence this composition, and (iii) analyze the effects of the lipid-lowering drug fenofibrate on the circulating BA-G profile in 300 volunteers and 5 cholestatic patients. Eleven BA-Gs were determined in pre- and postfenofibrate samples. Men exhibited higher BA-G concentrations, and various genotype/BA-G associations were discovered in relevant UGT genes. The chenodeoxycholic acid-3G (CDCA-3G) concentration was associated with the UGT2B7 802C>T polymorphism. Glucuronidation assays confirmed the predominant role of UGT2B7 and UGT1A4 in CDCA-3G formation. Fenofibrate exposure increased the serum levels of five BA-G species, including CDCA-3G, and upregulated expression of UGT1A4, but not UGT2B7, in hepatic cells. This study demonstrated that fenofibrate stimulates BA glucuronidation in humans and thus reduces BA toxicity in the liver.Clinical Pharmacology & Therapeutics (2013); 94 4, 533-543. doi:10.1038/clpt.2013.122. PMID:23756370

Trottier, J; Perreault, M; Rudkowska, I; Levy, C; Dallaire-Theroux, A; Verreault, M; Caron, P; Staels, B; Vohl, M-C; Straka, R J; Barbier, O

2013-06-12

51

Chemometric evaluation of nine alcohol biomarkers in a large population of clinically-classified subjects: pre-eminence of ethyl glucuronide concentration in hair for confirmatory classification.  

PubMed

An important goal of forensic and clinical toxicology is to identify biological markers of ethanol consumption that allow an objective diagnosis of chronic alcohol misuse. Blood and head hair samples were collected from 175 subjects-objectively classified as non-drinkers (N=65), social drinkers (N=51) and active heavy drinkers (N=59)-and analyzed to determine eight traditional indirect biomarkers of ethanol consumption [aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyltransferase (?-GT), alkaline phosphatase (ALP), mean corpuscular volume (MCV), carbohydrate-deficient transferrin (CDT), and cholesterol and triglycerides in blood] and one direct biomarker [ethyl glucuronide (EtG) in head hair]. The experimental values obtained from these determinations were submitted to statistical evaluations. In particular, Kruskal-Wallis, Mann-Whitney and ROC curve analyses, together with principal component analysis (PCA), allowed the diagnostic performances of the various biomarkers to be evaluated and compared consistently. From these evaluations, it was possible to deduce that EtG measured in head hair is the only biomarker that can conclusively discriminate active heavy drinkers from social and non-drinkers, using a cut-off value of 30 pg/mg. In contrast, a few indirect biomarkers such as ALP, cholesterol, and triglycerides showed extremely low diagnostic abilities and may convey misleading information. AST and ALT proved to be highly correlated and exhibited quite low sensitivity and specificity. Consequently, either of these parameters can be discarded without compromising the classification efficiency. Among the indirect biomarkers, ?-GT provided the highest diagnostic accuracy, while CDT and MCV yielded high specificity but low sensitivity. It was therefore concluded that EtG in head hair is the only biomarker capable of supporting a confirmatory diagnosis of chronic alcohol abuse in both forensic and clinical practice, while it was found that ?-GT, CDT, MCV, and AST--whether used alone or in combination--do not allow the conclusive classification of subjects according to ethanol consumption. However, a diagnostic strategy combining these four parameters could be formulated in order to create a multivariate model capable of screening suspected active heavy drinkers. PMID:21901464

Pirro, Valentina; Valente, Valeria; Oliveri, Paolo; De Bernardis, Angela; Salomone, Alberto; Vincenti, Marco

2011-09-04

52

Determination of ajulemic acid and its glucuronide in human plasma by gas chromatography-mass spectrometry.  

PubMed

A method using gas chromatography-mass spectrometry (GC-MS) and solid-phase extraction (SPE) was developed for the determination of ajulemic acid (AJA), a non-psychoactive synthetic cannabinoid with interesting therapeutic potential, in human plasma. When using two calibration graphs, the assay linearity ranged from 10 to 750 ng/ml, and 750 to 3000 ng/ml AJA. The intra- and inter-day precision (R.S.D., %), assessed across the linear ranges of the assay, was between 1.5 and 7.0, and 3.6 and 7.9, respectively. The limit of quantitation (LOQ) was 10 ng/ml. The amount of AJA glucuronide was determined by calculating the difference in the AJA concentration before ("free AJA") and after enzymatic hydrolysis ("total AJA"). The present method was used within a clinical study on 21 patients suffering from neuropathic pain with hyperalgesia and allodynia. For example, plasma levels of 599.4+/-37.2 ng/ml (mean+/-R.S.D., n=9) AJA were obtained for samples taken 2 h after the administration of an oral dose of 20 mg AJA. The mean AJA glucuronide concentration at 2h was 63.8+/-127.9 ng/ml. PMID:15866495

Batista, Catarina; Berisha, Myftar; Karst, Matthias; Salim, Kahlid; Schneider, Udo; Brenneisen, Rudolf

2005-04-12

53

Regiospecificity of human UDP-glucuronosyltransferase isoforms in chalcone and flavanone glucuronidation determined by metal complexation and tandem mass spectrometry.  

PubMed

The glucuronidation of a series of chalcones (2'-hydroxychalcone, 2',4'-dihydroxychalcone, 3,2'-dihydroxychalcone, 4,2'-dihydroxychalcone, and cardamonin) and their corresponding cyclized flavanones (7-hydroxyflavanone, 3'-hydroxyflavanone, 4'-hydroxyflavanone, and alpinetin) by eight human UDP-glucuronosyltransferase (UGT) 1A enzymes was evaluated. A postcolumn metal complexation LC-MS/MS strategy was used successfully to produce characteristic mass spectrometric product ions that were utilized in combination with elution order trends to identify chalcone and flavanone monoglucuronides unambiguously, thus allowing determination of the regioselectivities of the UGT1A isoforms. The presence of hydroxy groups on the A- or B-ring had a significant effect on the glucuronide product yield and the site where glucuronidation occurred. For example, for reaction with UGT1A9, formation of the 2'-O-glucuronide was increased for dihydroxychalcones with A-ring hydroxy substituents. In contrast, although UGT1A8 reacted with 3,2'-dihydroxychalcone and 4,2'-dihydroxychalcone to yield 2'-O-glucuronide products, the presence of a B-ring hydroxy group at the 4' position on cardamonin and 2',4'-dihydroxychalcone quenched the reaction at the OH-2' position. Moreover, the A-ring OH-4 group promoted glucuronidation at the 2' position for the reaction of 4,2'-dihydroxychalcone with UGT1A1 and 1A3. For UGT1A7, hydroxy group substituents on the chalcone A-ring also promoted cyclization and formation of the corresponding flavanone glucuronide. PMID:23713759

Niemeyer, Emily D; Brodbelt, Jennifer S

2013-05-29

54

A fatal clomipramine intoxication case of a chronic alcoholic patient: application of postmortem hair analysis method of clomipramine and ethyl glucuronide using LC/APCI/MS.  

PubMed

Toxicological investigations of postmortem specimens of a 26-year-old man were performed with the use of LC/APCI/MS. They revealed in the blood of the deceased clomipramine (9.49 microg/g) and its main metabolite norclomipramine (1.10 microg/g) at concentrations explaining the fatal outcome. The presence of these xenobiotics in a 12-cm-long strand of hair (clomipramine, 7.60 ng/mg in I segment; 4.19 ng/mg in II segment; 1.86 ng/mg in III segment; norclomipramine, 5.71 ng/mg in I segment; 9.71 ng/mg in II segment; 4.13 ng/mg in III segment) confirmed the fact obtained from the medical history that the deceased had been receiving clomipramine as an antidepressant for 1 year prior to his death. The analysis demonstrated ethanol in autopsy blood (2.5mg/ml) and urine (3.2mg/ml); ethyl glucuronide as a marker of chronic alcohol abuse was detected in the deceased's hair (0.44 ng/mg in I segment; 0.07 ng/mg in II segment; n.d. in III segment). These findings may suggest the contribution of alcohol in the mechanism of drug-ethanol interaction, which in consequence might have affected the biotransformation of clomipramine in the final period of his life and evoked the ultimate toxic effect. PMID:16046273

K?ys, Ma?gorzata; Scis?owski, Mariusz; Rojek, Sebastian; Ko?odziej, Jan

2005-10-01

55

Determination of morphine and its 3- and 6-glucuronides, codeine, codeine-glucuronide and 6-monoacetylmorphine in body fluids by liquid chromatography atmospheric pressure chemical ionization mass spectrometry  

Microsoft Academic Search

A selective assay of morphine-3-glucuronide (M3G), morphine-6-glucuronide (M6G), morphine, codeine, codeine-6-glucuronide (C6G) and 6-monoacetylmorphine (6-MAM) based on liquid chromatography atmospheric pressure chemical ionization mass spectrometry (LC–APCI–MS) is described. The drugs were extracted from serum, autopsy blood, urine, cerebrospinal fluid or vitreous humor using C18 solid-phase extraction cartridges and subjected to LC–APCI–MS analysis. The separation was performed on an ODS column

Maciej J Bogusz; Rolf-Dieter Maier; Manfred Erkens; Sarah Driessen

1997-01-01

56

Routine determination of morphine, morphine 3-?- d-glucuronide and morphine 6-?- d-glucuronide in human serum by liquid chromatography coupled to electrospray mass spectrometry  

Microsoft Academic Search

A robust liquid chromatographic mass spectrometric method capable of quantifying morphine, morphine 3-?-d-glucuronide and morphine 6-?-d-glucuronide down to 1.0 ng\\/ml, 5.0 ng\\/ml and 2.0 ng\\/ml respectively in human serum is presented. The method was validated over linear ranges of 1.0 to 20.0 ng\\/ml for morphine, 5.0 to 500.0 ng\\/ml for morphine 3-?-d-glucuronide and 2.0 to 100.0 ng\\/ml for morphine 6-?-d-glucuronide

M Blanchet; G Bru; M Guerret; M Bromet-Petit; N Bromet

1999-01-01

57

Simultaneous determination of THC-COOH and THC-COOH-glucuronide in urine samples by LC/MS/MS.  

PubMed

A fast method using liquid-liquid extraction and HPLC/tandem-mass spectrometry (LC/MS/MS) was developed for the simultaneous detection of 11-Nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid beta-glucuronide (THC-COOH-glucuronide) and 11-Nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in urine samples. This highly specific method, which combines chromatographic separation and MS/MS analysis, can be used for the confirmation of positive immunoassay results even without hydrolysis of the sample or derivatisation of extracts. Liquid-liquid extraction was optimised: with ethylacetate/diethylether (1:1, v/v) THC-COOH-glucuronide and THC-COOH could be extracted in one step. Molecular ions of the glucuronide (MH(+), m/z 521) and THC-COOH (MH(+), m/z 345) were generated using a PE/SCIEX turboionspray source in positive ionisation mode; specific fragmentation was performed in the collision cell of an API 365 triple-quadrupole mass spectrometer and yielded major fragments at m/z 345 (for THC-COOH-glucuronide) and m/z 327 as well as m/z 299 for both cannabinoids. Chromatographic separation was performed using a reversed-phase C8 column and gradient elution with 0.1% formic acid/1 mM ammonium formate and acetonitrile/0.1% formic acid. Retention times were 22.2 min for the glucuronide and 26.8 min for THC-COOH. After enzymatic hydrolysis of urine samples with beta-glucuronidase/arylsulfatase (37 degrees C, 5 h), THC-COOH-glucuronide was no longer detectable by LC/MS/MS in urine samples. However, the THC-COOH concentration was increased. For quantitation of THC-COOH, THC-COOH-D(3) was added to the urine samples as internal standard prior to analysis. From the difference of THC-COOH in the native urine and urine after enzymatic hydrolysis, molar concentration ratios of THC-COOH-glucuronide/THC-COOH in urine samples of cannabis users were determined and found to be between 1.3 and 4.5. PMID:10978652

Weinmann, W; Vogt, S; Goerke, R; Müller, C; Bromberger, A

2000-09-11

58

Ethyl glucuronide concentrations in oral fluid, blood, and urine after volunteers drank 0.5 and 1.0 g/kg doses of ethanol.  

PubMed

The aim of this study was to investigate the concentrations of ethyl glucuronide (EtG) in oral fluid, blood, and urine after healthy volunteers drank two doses of ethanol, 0.5 (n = 11) and 1.0 g/kg (n = 10), after an overnight fast. Samples of oral fluid, blood, and urine were collected before drinking started and at 1.5, 3.5, 5.5, 8.5, 11.5, and 24 h post-dosing. Following ingestion of low dose of ethanol, the Cmax for EtG was 0.36 mg/L (range 0.28-0.41 mg/L) in blood and 69.8 mg/L (range 47.1-96.5 mg/L) in urine. In oral fluid, the concentrations were < 1% of those in blood, and only three subjects exceeded the limit of quantification for EtG in oral fluid. After ingestion of the high dose of ethanol, the Cmax for EtG was 1.06 mg/L (range 0.8-1.22 mg/L) in blood, 159.9 mg/L (range 97.2-225.5 mg/L) in urine, and 0.032 mg/L (range 0.013-0.059 mg/L) in oral fluid. The median oral fluid/blood ratio was 0.029 (range 0.012-0.054) for EtG. The detection time for EtG was median 11.5 h (range 3.5-11.5 h) in oral fluid. According to this, the detection time for EtG in oral fluid is therefore only a few hours longer than for ethanol itself and represents limited additional value. PMID:20663284

Høiseth, Gudrun; Yttredal, Borghild; Karinen, Ritva; Gjerde, Hallvard; Mørland, Jørg; Christophersen, Asbjørg

59

Determination of morphine, morphine-3-glucuronide and morphine-6-glucuronide in monkey and dog plasma by high-performance liquid chromatography–electrospray ionization tandem mass spectrometry  

Microsoft Academic Search

A specific and simultaneous assay of morphine, morphine-3-glucuronide (M-3-G) and morphine-6-glucuronide (M-6-G) in monkey and dog plasma has been developed. These methods are based on rapid isolation using solid phase extraction cartridge, and high-performance liquid chromatography (HPLC)–electrospray ionization (ESI)-tandem mass spectrometric (MSMS) detection. Analytes were separated on a semi-micro ODS column in acetonitrile–formic (or acetic) acid mixed solution. The selected

Masanari Mabuchi; Satomi Takatsuka; Masayuki Matsuoka; Kozo Tagawa

2004-01-01

60

Autism and phthalate metabolite glucuronidation.  

PubMed

Exposure to environmental chemicals may precipitate autism spectrum disorders (ASD) in genetically susceptible children. Differences in the efficiency of the glucuronidation process may substantially modulate substrate concentrations and effects. To determine whether the efficiency of this pathway is compromised in children with ASD, we measured the efficiency of glucuronidation for a series of metabolites derived from the commonly used plasticizer, diethylhexyl phthalate. Spot urines were collected and analyzed for the fraction of each metabolite conjugated by isotope dilution-liquid chromatography mass spectrometry-mass spectrometry. The degree of glucuronidation was lower with the ASD group. The glucuronidation pathway may differ in some children with ASD. PMID:23575644

Stein, T Peter; Schluter, Margaret D; Steer, Robert A; Ming, Xue

2013-11-01

61

Determining the partial photoionization cross-sections of ethyl radicals.  

PubMed

Using a crossed laser-molecular beam scattering apparatus, these experiments photodissociate ethyl chloride at 193 nm and detect the Cl and ethyl products, resolved by their center-of-mass recoil velocities, with vacuum ultraviolet photoionization. The data determine the relative partial cross-sections for the photoionization of ethyl radicals to form C2H5+, C2H4+, and C2H3+ at 12.1 and 13.8 eV. The data also determine the internal energy distribution of the ethyl radical prior to photoionization, so we can assess the internal energy dependence of the photoionization cross-sections. The results show that the C2H4++H and C2H3++H2 dissociative photoionization cross-sections strongly depend on the photoionization energy. Calibrating the ethyl radical partial photoionization cross-sections relative to the bandwidth-averaged photoionization cross-section of Cl atoms near 13.8 eV allows us to use these data in conjunction with literature estimates of the Cl atom photoionization cross-sections to put the present bandwidth-averaged cross-sections on an absolute scale. The resulting bandwidth-averaged cross-section for the photoionization of ethyl radicals to C2H5+ near 13.8 eV is 8+/-2 Mb. Comparison of our 12.1 eV data with high-resolution ethyl radical photoionization spectra allows us to roughly put the high-resolution spectrum on the same absolute scale. Thus, one obtains the photoionization cross-section of ethyl radicals to C2H5+ from threshold to 12.1 eV. The data show that the onset of the C2H4++H dissociative photoionization channel is above 12.1 eV; this result offers a simple way to determine whether the signal observed in photoionization experiments on complex mixtures is due to ethyl radicals. We discuss an application of the results for resolving the product branching in the O+allyl bimolecular reaction. PMID:17760439

FitzPatrick, B L; Maienschein-Cline, M; Butler, L J; Lee, S-H; Lin, J J

2007-08-31

62

Simultaneous spectrophotometric determination of maltol, ethyl maltol, vanillin and ethyl vanillin in foods by multivariate calibration and artificial neural networks  

Microsoft Academic Search

Maltol (MAL), ethyl maltol (EMA), vanillin (VAN) and ethyl vanillin (EVA) are food additives, and they have well defined UV spectra. However, these overlapped seriously, and it is difficult to determine them individually from their mixtures without a pre-separation. In this paper, chemometric approaches were applied to resolve the overlapping spectra and to determine these compounds simultaneously. The analysis of

Yongnian Ni; Guowen Zhang; Serge Kokot

2005-01-01

63

Gender and oral contraceptive steroids as determinants of drug glucuronidation: effects on clofibric acid elimination.  

PubMed Central

The disposition of clofibric acid, a drug metabolised largely by glucuronidation, was studied in eight males, eight females and eight females receiving oral contraceptive steroids (OCS). Clofibric acid plasma clearance was not significantly different in males compared to the control female group but was 48% greater (P less than 0.01) in women receiving OCS compared to non-pill using females. This difference was due to an alteration in clofibric acid metabolic clearance as there were no differences between the groups in clofibric acid free fraction. Along with previous data the results suggest that induction of drug glucuronidation by OCS may be of clinical importance, although any sex-related differences are unlikely to be of clinical significance.

Miners, J O; Robson, R A; Birkett, D J

1984-01-01

64

Isolation and determination of benzo(a)pyrene glucuronide and sulfate conjugates in soybean leaves  

SciTech Connect

BaP is metabolized in mammalian systems by the mixed function oxidase system of liver microsomes. This system catalyzes the oxidation of BaP via epoxide intermediate to phenol, diol and quinone metabolites. One of these 7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydro-BaP is thought to act as the ultimate carcinogen by binding covalently to cellular DNA. It is also known that Cunninghamella elegans oxidized BaP to its phenol, diol and quinone metabolites. In addition, the alcohols were detected as glucuronide and sulfate conjugates. These metabolites are remarkably similar to those observed in higher organisms. On the other hand, some investigators have demonstrated that plants take up BaP and anthracene from soil or culture medium containing these compounds. This paper reports the finding that soybeans grown in BaP polluted soil take it up and metabolize to its phenol, diol and the glucuronide and sulfate conjugates of the alcohols.

Negishi, T.; Nakano, M.; Kobayashi, S.; Kim, C.H.

1987-08-01

65

Determination of testosterone and epitestosterone glucuronides in urine by ultra performance liquid chromatography-ion mobility-mass spectrometry.  

PubMed

UPLC-ion mobility spectrometry separations combined with mass spectrometry (UPLC-IM-MS) and tandem mass spectrometry (UPLC-IM-MS/MS) have been investigated for the simultaneous determination of testosterone and epitestosterone glucuronides in urine. The glucuronide epimers of testosterone and epitestosterone were separated by ion mobility spectrometry prior to mass analysis on the basis of differences in their collision cross sections, which have been measured in nitrogen. Combining ion mobility separation with UPLC/MS enhances the analysis of these low-abundance steroids in urine by selective interrogation of specific retention time, mass-to-charge and mobility regions. Detection limits for the UPLC-IM-MS/MS analysis of TG and ETG were 9.9 ng mL(-1) and 98 ng mL(-1) respectively, equivalent to 0.7 ng mL(-1) and 7.4 ng mL(-1) in urine, with linear dynamic ranges corresponding to 0.7-108 ng mL(-1) and 7.4-147 ng mL(-1) in urine. Repeatability (%RSD) for urine extracts was 0.64% and 2.31% for TG and ETG respectively. PMID:21842047

Kaur-Atwal, Gushinder; Reynolds, James C; Mussell, Christopher; Champarnaud, Elodie; Knapman, Tom W; Ashcroft, Alison E; O'Connor, Gavin; Christie, Steven D R; Creaser, Colin S

2011-08-12

66

Steroid and steroid glucuronide profiles in urine during pregnancy determined by liquid chromatography-electrospray ionization-tandem mass spectrometry.  

PubMed

An ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-MS/MS) method was developed for the analysis of steroids and their glucuronides in urine samples. The method provides high sensitivity and fast analysis, as both steroids and their glucuronides can be analyzed directly without hydrolysis or complex sample preparation. The method was applied in profiling of targeted and nontargeted steroids and steroid glucuronides during pregnancy. The concentrations of 11 of 27 targeted steroids and steroid glucuronides and the concentrations of 25 nontargeted steroid glucuronides increased about 10-400 fold during the pregnancy. The concentrations of most of these 36 compounds began to increase in the first days of the pregnancy, increased gradually during the pregnancy, achieved a maximum in late pregnancy, and decreased sharply after delivery. Exceptionally, the concentrations of allopregnanolone and 17-hydroxypregnenolone started to increase later than those of the other steroids. Moreover, the concentrations of E2 glucuronides began to decrease one week before the delivery, in contrast to most of the steroids and steroid glucuronides, whose concentrations dropped sharply during the delivery. Concentrations of 34 compounds decreased noticeably when the subject was on sick leave owing a series of painful contractions. The results suggest that steroids and especially steroid glucuronides may provide a valuable diagnostic tool to follow the course of pregnancy. PMID:24176505

Jäntti, Sirkku E; Hartonen, Minna; Hilvo, Mika; Nygren, Heli; Hyötyläinen, Tuulia; Ketola, Raimo A; Kostiainen, Risto

2013-09-30

67

Determination of ethyl carbamate in some fermented Korean foods and beverages  

Microsoft Academic Search

Ethyl carbamate has been associated with cancer for several decades. It is mainly found in fermented foods and beverages. In view of the importance of fermented foods in the Korean diet and the significant level of ethyl carbamate expected, we determined ethyl carbamate concentrations in some of the staple food items and estimated the daily intake for the Korean population.

Young-Kyunge Le Kim; Eunmi Koh; Hyun-Jung Chung; Hoonjeong Kwon

2000-01-01

68

75 FR 82069 - Ethyl Alcohol for Fuel Use: Determination of the Base Quantity of Imports  

Federal Register 2010, 2011, 2012, 2013

...Investigation No. 332-288] Ethyl Alcohol for Fuel Use: Determination of the Base Quantity of Imports...quantity'' of imports of fuel ethyl alcohol with a zero percent local...level of U.S. consumption of fuel ethyl alcohol to be 12.506 billion...

2010-12-29

69

Determination of mycophenolic acid glucuronide in microsomal incubations using high performance liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

A sensitive and specific HPLC–MS\\/MS method was developed for the analysis of mycophenolic acid glucuronide (MPAG) in incubations with human liver microsomes. Incubation samples were processed by protein precipitation with acetonitrile. MPAG and the internal standard phenolphthalein glucuronide were chromatographed on a C18 Synergi Fusion-RP column (100mm×2mm, 4?m) using gradient elution with a mixture of 1mM acetic acid in deionized

Mohamed-Eslam F. Mohamed; Stephen S. Harvey; Reginald F. Frye

2008-01-01

70

Simultaneous determination of morphine, oxycodone, morphine-3-glucuronide, and noroxycodone concentrations in rat serum by high performance liquid chromatography–electrospray ionization–tandem mass spectrometry  

Microsoft Academic Search

An assay using high performance liquid chromatography (HPLC)–electrospray ionization–tandem mass spectrometry (ESI–MS–MS) was developed for simultaneously determining concentrations of morphine, oxycodone, morphine-3-glucuronide, and noroxycodone, in 50?l samples of rat serum. Deuterated (d3) analogues of each compound were used as internal standards. Samples were treated with acetonitrile to precipitate plasma proteins; acetonitrile was removed from the supernatant by centrifugal evaporation before

Stephen R. Edwards; Maree T. Smith

2005-01-01

71

Determination of Fenoxaprop-Ethyl in Agricultural Products by HPLC with Photometric Detection and Mass  

Microsoft Academic Search

A method was developed for the determination of 6-chloro-2,3-dihydrobenzoxazol-2-one (CDHB) gener- ated by the acid decomposition of fenoxaprop-ethyl and fenoxaprop in agricultural products. Fenoxaprop-ethyl and fenoxaprop were extracted from agricultural prod- ucts using acetonitrile, and the extract was acidified by 0.5 mol\\/l hydrochloric acid to make CDHB. The CDHB was extracted again into ethyl acetate and cleaned up using Sep-Pak®

Spectrometry Susumu Ishimitsu; Kimihiko Yoshii; Yukari Tsumura; Yasuhide Tonogai

72

Determination of ajulemic acid and its glucuronide in human plasma by gas chromatography–mass spectrometry  

Microsoft Academic Search

A method using gas chromatography–mass spectrometry (GC–MS) and solid-phase extraction (SPE) was developed for the determination of ajulemic acid (AJA), a non-psychoactive synthetic cannabinoid with interesting therapeutic potential, in human plasma. When using two calibration graphs, the assay linearity ranged from 10 to 750ng\\/ml, and 750 to 3000ng\\/ml AJA. The intra- and inter-day precision (R.S.D., %), assessed across the linear

Catarina Batista; Myftar Berisha; Matthias Karst; Kahlid Salim; Udo Schneider; Rudolf Brenneisen

2005-01-01

73

Iso-Glucuronides.  

PubMed

This review on isomers or acyl glucuronides (iso-glucuronides) updates earlier reviews, and attempts to place in context the advances that have been made, especially over the last 15 years. The essential chemistry behind the intramolecular acyl migration and anomerization reactions of acyl glucuronides has been appreciated for 30 years. The great advances in the past 15 years have been in understanding the dynamics and kinetics of these processes in vitro, using highly sophisticated modern technology, e.g. LC-NMR, LC-MS/MS. In this way, earlier assumptions on kinetics and identification of migration isomers and anomers have come under intense review and update. Extensive structure-activity relationships, involving electronic and steric characteristics of an acyl glucuronide and its possible 7 isomers (excluding transient open-chain species) have been delineated. The covalent modification of endogenous proteins and other macromolecules has been further explored, though direct linkage between such modification and toxic sequelae remains elusive. An alternative view of acyl glucuronides and iso-glucuronides as just xenobiotics has perhaps added the dimension that acyl glucuronidation (and attendant formation of iso-glucuronides) does not necessarily mean that glucuronidation of the aglycone has ended metabolic sequences in vivo. PMID:21342113

Dickinson, Ronald G

2011-02-21

74

Iso-glucuronides.  

PubMed

This review on isomers or acyl glucuronides (iso-glucuronides) updates earlier reviews, and attempts to place in context the advances that have been made, especially over the last 15 years. The essential chemistry behind the intramolecular acyl migration and anomerization reactions of acyl glucuronides has been appreciated for 30 years. The great advances in the past 15 years have been in understanding the dynamics and kinetics of these processes in vitro, using highly sophisticated modern technology, e.g. LC-NMR, LC-MS/MS. In this way, earlier assumptions on kinetics and identification of migration isomers and anomers have come under intense review and update. Extensive structure-activity relationships, involving electronic and steric characteristics of an acyl glucuronide and its possible 7 isomers (excluding transient open-chain species) have been delineated. The covalent modification of endogenous proteins and other macromolecules has been further explored, though direct linkage between such modification and toxic sequelae remains elusive. An alternative view of acyl glucuronides and iso-glucuronides as just xenobiotics has perhaps added the dimension that acyl glucuronidation (and attendant formation of iso-glucuronides) does not necessarily mean that glucuronidation of the aglycone has ended metabolic sequences in vivo. PMID:21395535

Dickinson, Ronald G

2011-03-01

75

Determination of 3-trifluoromethyl-4-nitrophenol and 3-trifluoromethyl-4-nitrophenol glucuronide in edible fillet tissue of rainbow trout and channel catfish by solid-phase extraction and liquid chromatography.  

PubMed

3-Trifluoromethyl-4-nitrophenol (TFM) is a pesticide used for the selective control of sea lampreys (Petromyzon marinus) in stream and river tributaries of the Great Lakes. To determine concentrations of TFM and TFM glucuronide in the edible fillet tissue of fish during sea lamprey control treatments, an analytical method was developed to determine the concentrations of these residues in rainbow trout (Oncorhynchus mykiss; RBT) and channel catfish (Ictalurus punctatis; CCF). Homogenized fillets were extracted with methanol-water (80 + 20). TFM and TFM glucuronide were isolated from coextractives by C18 solid-phase extraction. TFM glucuronide was hydrolyzed to TFM by the addition of beta-glucuronidase to the TFM glucuronide extract. The extracts were analyzed separately by liquid chromatography with UV-visible detection. Recoveries from TFM-fortified CCF and RBT tissues were 84.1 and 96.1%, respectively. The method detection limits (MDLs) are 2.4 ng/g for TFM-fortified tissues of CCF and 3 ng/g for those of RBT. Recoveries were 78.8 and 77% from TFM glucuronide-fortified CCF and RBT tissues, respectively. The MDLs for TFM glucuronide-fortified tissues are 3.5 and 6.9 ng/g for CCF and RBT, respectively. PMID:11324603

Hubert, T D; Vue, C; Bernardy, J A; Van Horsen, D L; Rossulek, M I

76

Simultaneous determination of buprenorphine, norbuprenorphine, and buprenorphine–glucuronide in plasma by liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

For the first time, an LC–MS–MS method has been developed for the simultaneous analysis of buprenorphine (BUP), norbuprenorphine (NBUP), and buprenorphine–glucuronide (BUPG) in plasma. Analytes were isolated from plasma by C18 SPE and separated by gradient RP-LC. Electrospray ionization and MS–MS analyses were carried out using a PE-Sciex API-3000 tandem mass spectrometer. The m\\/z 644?m\\/z 468 transition was monitored for

Aldo Polettini; Marilyn A Huestis

2001-01-01

77

Determination of Uranium by the TBP Method after Extraction with Ethyl Acetate.  

National Technical Information Service (NTIS)

The method involves the fusion of the sample with potassium pyrosulphate and precipitation of the uranium with ammonium hydroxide. The precipitate is redissolved in nitric acid, and the uranium is extracted into ethyl acetate. The uranium is determined on...

B. T. Eddy J. D. Spangenberg B. G. Russell T. W. Steele

1968-01-01

78

The Determination of Diphenylamine and Ethyl Centralite in Type Ar5401 Propellant.  

National Technical Information Service (NTIS)

The determination of diphenylamine and ethyl centralite in propellant AR5401 by various methods has been examined. Separation from the propellant base (nitrocellulose) was effected by both solvent extraction and steam distillation. UV absorption, gas-liqu...

R. G. Davidson A. G. Kelso

1972-01-01

79

Determination of resveratrol and its sulfate and glucuronide metabolites in plasma by LC-MS/MS and their pharmacokinetics in dogs  

PubMed Central

An analytical approach for the determination of trans-resveratrol (3,5,4?-trihydroxy-trans-stilbene) and its glucuronide and sulfate conjugates in dog plasma by LC-MS/MS (without enzymatic hydrolysis of the conjugates) was validated to support pre-clinical toxicological and pharmacological studies. The approach required two independent sample extractions and consequent instrument runs. Samples for resveratrol determination were prepared by protein precipitation with acetonitrile; acetonitrile-methanol was used instead for resveratrol metabolites. Chromatographic separation was performed using a C18 column (30 × 2.0 mm) at a flow rate of 0.25 mL/min. For resveratrol the mobile phase consisted of A: 5 mM ammonium acetate in water-isopropanol (98:2, v/v) and B: methanol-isopropanol (98:2, v/v) and for metabolites the mobile phase was modified as follows: A: 0.1% (v/v) formic acid in water and B: 0.1% (v/v) formic acid in acetonitrile. Total run time was 12 min for each run with retention times of about 4-5 min for all analytes. A turbo ion spray source was used operating in negative mode for resveratrol and resveratrol sulfate and in positive mode for resveratrol glucuronide. Calibration curves were linear from 5 to 1000 ng/mL for resveratrol and its glucuronide, and 10 to 2000 ng/mL for resveratrol sulfate. Linearity was assessed using the internal standard method for resveratrol and the external standard method for the metabolites. Method accuracy was 90 to 112% of the true value for all analytes with precision of 9 %RSD or less for all validation experiments. The validated method was applied to a preclinical toxicology study in dogs after oral administration (200 to 1200 mg/kg) of the agent. Peak plasma resveratrol concentration (Cmax) for most animals was observed within 1 to 5 h of dosing, with group mean values in the 1.7 to 9.9 ?g/mL (7.5 to 43 ?M) range. Area under the plasma concentration-time curve (AUC) mean values for resveratrol ranged from 3.6 to 44 h*?g/mL for all study groups and were generally proportional to the dose, with no consistent statistically significant changes observed for gender or number of doses. Mean molecular-weight adjusted ratios of resveratrol metabolites to resveratrol for AUC ranged from 1 to 9 for resveratrol glucuronide and from 2 to 11 for resveratrol sulfate.

Muzzio, Miguel; Huang, Zhihua; Hu, Shu-Chieh; Johnson, William D.; McCormick, David L.; Kapetanovic, Izet M.

2011-01-01

80

Determination of free and glucuronide conjugated 20-hydroxyarachidonic acid (20-HETE) in urine by gas chromatography/negative ion chemical ionization mass spectrometry.  

PubMed

20-Hydroxy-arachidonic acid (20-HETE) was determined in urine by an isotope dilution assay using gas chromatography/mass spectrometry (GC/MS). After addition of 18O2-internal standard, 20-HETE was extracted from urine with hexane either directly or after treatment with glucuronidase. 20-HETE was derivatized to the pentafluorobenzylester and the sample was applied to thin layer chromatography with iso-octane/iso-propanol 9:1 (v/v) as the developing solvent. The corresponding zone was extracted and 20-HETE was hydrogenated. After derivatization to the trimethylsilylether, 20-HETE was determined by GC/MS using the [M-pentafluorobenzyl]- -ion in the negative ion chemical ionization mode. Excretion rates of free and glucuronide conjugated 20-HETE was determined in healthy children and in children with hyperprostaglandin-E-syndrome/antenatal Bartter syndrome (HPS/aBS) with or without indomethacin treatment. Compared to the controls, the HPS/aBS children showed higher excretion rates of 20-HETE, which were suppressed to normal values under indomethacin medication. Free and glucuronide conjugated 20-HETE do not correlate with PGE2 excluding any participation in HPS/aBS. PMID:10841040

Watzer, B; Reinalter, S; Seyberth, H W; Schweer, H

2000-03-01

81

Lithocholate glucuronide is a cholestatic agent.  

PubMed Central

Lithocholic acid and its taurine, glycine, and sulfate derivatives are potent cholestatic agents. Lithocholate glucuronide is present in the plasma and urine of patients with cholestatic syndromes, but little is known of its metabolism, excretion, and cholestatic potential. [3 beta-3H]lithocholate 3-O-beta-D-glucuronide was synthesized, and chemical and radiochemical purity were established. The aqueous solubility of lithocholate glucuronide was determined and found to be greater than that of lithocholic acid or several of its derivatives. In the range of concentrations examined, calcium ions precipitated lithocholate glucuronide stoichiometrically. The material was administered to rats prepared with an external biliary fistula. When 17-25 micrograms quantities were administered, 89.1 +/- 4.5% (mean +/- SEM) of the radiolabel was secreted in bile within the first 20 h after administration, the major fraction being secreted in less than 20 min. Four-fifths of the radiolabeled material in bile was the administered unaltered parent compound, while a minor fraction consisted of a more polar derivative(s). We showed that increasing biliary concentrations of more polar derivatives were observed with milligram doses of [3H]lithocholate glucuronide, and with time after the administration of these loading doses. Milligram doses of [3H]lithocholate glucuronide resulted in partial or complete cholestasis. When induced cholestasis was partial, secretion in bile remained the primary excretory route (82.5-105.6% recovery in bile), while, when complete cholestasis was induced, wide tissue distribution of radiolabel was observed. Cholestasis developed rapidly during infusion of [3H]lithocholate glucuronide. Bile flow was diminished within 10-20 min of the start of an infusion of 0.05 mumol, 100 g-1 body weight, minute-1, administered concomitantly with an equimolar infusion of taurocholate. The results establish that lithocholate glucuronide exerts cholestatic effects comparable to those exerted by unconjugated lithocholic acid. Images

Oelberg, D G; Chari, M V; Little, J M; Adcock, E W; Lester, R

1984-01-01

82

Involvement of UDP-glucuronosyltransferases UGT1A9 and UGT2B7 in ethanol glucuronidation, and interactions with common drugs of abuse.  

PubMed

Ethyl glucuronide (EtG) determination is increasingly used in clinical and forensic toxicology to document ethanol consumption. The enzymes involved in EtG production, as well as potential interactions with common drugs of abuse, have not been extensively studied. Activities of human liver (HLM), kidney (HKM), and intestinal (HIM) microsomes, as well as of 12 major human recombinant UDP-glucuronosyltransferases (UGTs), toward ethanol (50 and 500 mM) were evaluated in vitro using liquid chromatography-tandem mass spectrometry. Enzyme kinetic parameters were determined for pooled microsomes and recombinant UGTs with significant activity. Individual contributions of UGTs were estimated using the relative activity factor approach, proposed for scaling activities obtained with cDNA-expressed enzymes to HLM. Interaction of morphine, codeine, lorazepam, oxazepam, nicotine, cotinine, cannabinol, and cannabidiol (5, 10, 15 mg/l) with ethanol (1.15, 4.6, 11.5 g/l; i.e., 25, 100, 250 mM) glucuronidation was assessed using pooled HLM. Ethanol glucuronidation intrinsic clearance (Cl(int)) was 4 and 12.7 times higher for HLM than for HKM and HIM, respectively. All recombinant UGTs, except UGT1A1, 1A6, and 1A10, produced EtG in detectable amounts. UGT1A9 and 2B7 were the most active enzymes, each accounting for 17 and 33% of HLM Cl(int), respectively. Only cannabinol and cannabidiol significantly affected ethanol glucuronidation. Cannabinol increased ethanol glucuronidation in a concentration-dependent manner, whereas cannabidiol significantly inhibited EtG formation in a noncompetitive manner (IC(50) = 1.17 mg/l; inhibition constant (K(i)) = 3.1 mg/l). UGT1A9 and 2B7 are the main enzymes involved in ethanol glucuronidation. In addition, our results suggest that cannabinol and cannabidiol could significantly alter ethanol glucuronidation. PMID:23230132

Al Saabi, Alaa; Allorge, Delphine; Sauvage, François-Ludovic; Tournel, Gilles; Gaulier, Jean-Michel; Marquet, Pierre; Picard, Nicolas

2012-12-10

83

CE Determination of 2-(9Carbazole)ethyl Chloroformate-Labeled Oligopeptides  

Microsoft Academic Search

A pre-column derivatization method for sensitive determination of oligopeptides, using the tagging reagent 2-(9-carbazole)ethyl\\u000a chloroformate (CEOC-Cl) followed by capillary electrophoresis (CE) with diode-array detection, has been developed. Maximum\\u000a yield close to 100% were observed when a three to fourfold molar excess of reagent was used at pH 9.0–10.0. Excess reagent\\u000a was extracted with n-hexane–ethyl acetate 9:1–10:1 (v\\/v); this enabled direct

Chenxu Ding; Xuejun Sun; Xianen Zhao; Wenchen Zhao; Yulin Li; Honglun Wang; Yourui Suo; Jinmao You

2008-01-01

84

Determination of odour detection thresholds for acetic acid and ethyl acetate in ice wine  

Microsoft Academic Search

Collectively acetic acid and ethyl acetate are responsible for ‘volatile acidity’ (VA) in wine. The detection limit or threshold for these compounds is well documented in table wine but not for ice wine. Knowledge of the ice wine thresholds is important for understanding perception limits and setting legal standards, particularly for a product with high intrinsic concentrations. Thresholds were determined

Margaret A. Cliff; Gary J. Pickering

2006-01-01

85

76 FR 82320 - Ethyl Alcohol for Fuel Use: Determination of the Base Quantity of Imports  

Federal Register 2010, 2011, 2012, 2013

...Commission has determined the level of U.S. consumption of fuel ethyl alcohol to be 12.955 billion gallons; 7 percent of this amount is 906.9 million gallons...Counsel at (202) 205-3091. The media should contact Margaret...

2011-12-30

86

Determination of Iodine Value in Ethylic Biodiesel Samples by 1H-NMR  

Microsoft Academic Search

An alternative method for the determination of iodine value in biodiesel samples obtained via ethylic route is proposed in this work. The method is based on the 1H NMR spectra where areas of the hydrogen signals observed at specific chemical shifts are integrated. The results demonstrated that there is a good correlation between data obtained by the traditional method and

S. Y. Red; R. J. S. Freitas

87

Impact of anti-cancer drugs and other determinants on serum protein binding of morphine 6-glucuronide  

PubMed Central

Background and the purpose of the study The aim of the present study was to examine factors that may influence the protein binding of morphine 6-glucuronide (M6G), the most active metabolite of morphine. Methods An enzyme-linked immunoabsorbent assay technique was used to measure the M6G concentration in serum of 18 healthy adults, 18 neonatal and 7 children with cancer. Total and free M6G concentrations were measured following equilibrium dialysis for 3 hrs and at physiological pH at 37°C. The influence of vincristine, methotrexate, 6-mercaptopurine, morphine, human albumin, alpha-1-acid glycoprotein, palmitic acid, oleic acid and pH on M6G protein binding was examined. Results M6G was 66.87±0.73 percent free in human serum at physiological pH and temperature. The percentage free (unbound) was increased significantly by vincristine (4.33%) and methotrexate (9.68%), but 6- mercaptopurine and morphine had no significant effect on it. Free percentages of M6G was reduced by decreasing serum albumin concentration but was unaffected by the presence of alpa-1-acid glycoprotein (AAG) or changes in serum pH. Similar results were obtained in human serum albumin (HAS) solutions. Addition of palmitic acid and oleic acid reduced protein binding significantly by 6.3% and 7.4%, respectively. Major conclusion Although M6G in this study was not highly bounded, but because of its high analgesic potency, any change in its free concentration due to concurrent medication or disease caused significant changes in its effects. This dearth of evidence has been implicated in the reluctance of professionals to be cautious in prescribing them to children, particularly in the neonatal period.

Mashayekhi, S.O.; Ghandforoush-Sattari, M.; Buss, D.C.; Routledge, P.A.; Hain, R.DW.

2010-01-01

88

LC 1H NMR used for determination of the elution order of S-naproxen glucuronide isomers in two isocratic reversed-phase LCsystems  

Microsoft Academic Search

The reactive metabolite S-naproxen-?-1-O-acyl glucuronide was purified from human urine using solid phase extraction (SPE) and preparative HPLC. The structure was confirmed by 600 MHz 1H NMR. Directly coupled 600 MHz HPLC-1H NMR was used to assign the peaks in chromatograms obtained when analysing a sample containing S-naproxen aglycone and the 1-, 2-, 3-, and 4-isomers of S-naproxen-?-1-O-acyl glucuronide in

Rasmus W. Mortensen; Olivia Corcoran; Claus Cornett; Ulla G. Sidelmann; Jeff Troke; John C. Lindon; Jeremy K. Nicholson; Steen Honoré Hansen

2001-01-01

89

High-performance liquid chromatographic method for the simultaneous determination of the camptothecin derivative irinotecan hydrochloride, CPT-11, and its metabolites SN-38 and SN-38 glucuronide in rat plasma with a fully automated on-line solid-phase extraction system, PROSPEKT.  

PubMed

We established a high-performance liquid chromatography (HPLC) method for the simultaneous determination of the camptothecin (CPT) derivative, irinotecan hydrochloride (CPT-11) and its metabolites, 7-ethyl-10-hydroxycamptothecin (SN-38) and SN-38 glucuronide (SN-38G) in rat plasma with a fully automated on-line solid-phase extraction system, PROSPEKT. Plasma samples were pretreated with 0.146 M H3PO4 to inactivate carboxylesterase and beta-glucuronidase in rat plasma, and added with the internal standard solution (0.146 M H3PO4 containing 1 microgram/ml CPT) and then analyzed. The method was validated for CPT-11 (5 to 25,000 ng/ml), SN-38 (5 to 2500 ng/ml) and SN-38G (2.5 to 500 ng/ml). This method enabled the determination of many samples within a relatively short time with easy sample preparation. It also had four advantages compared with conventional determination methods, i.e. automation of a complicated sample preparation, time-saving by the simultaneous determination of three compounds, the direct determination of SN-38G, and the small amount of plasma required for the determination. PMID:10219676

Kurita, A; Kaneda, N

1999-03-19

90

Determination of total mycophenolic acid and its glucuronide metabolite using liquid chromatography with ultraviolet detection and unbound mycophenolic acid using tandem mass spectrometry.  

PubMed

Two simple, sensitive and reproducible methods for determination of total mycophenolic acid (MPA) and its glucuronide metabolite (MPAG) as well as unbound MPA (fMPA) was developed by the use of HPLC-UV and LC-MS/MS methods, respectively. For the total MPA/MPAG method, the analytes were extracted using Isolute C(2) solid-phase extraction (SPE) cartridges and analyzed at 254 nm over a Zorbax Rx C(8) column (150 mm x 4.6 mm, 5 microm). The mobile phase was a gradient mixture of methanol and water (containing 0.1% (v/v) phosphoric acid). The total run time was 18 min and the extraction recovery was 77% for MPA and 84% for MPAG. The method was precise and accurate with a lower limit of quantification (LLOQ) of 0.5 mg/l for MPA and 5.0 mg/l for MPAG. For the fMPA method, plasma was subjected to ultrafiltration followed by SPE using C(18) cartridges. Analytical column was the same as the HPLC-UV method and the mobile phase was a gradient composition of methanol:0.05% formic acid with a flow rate of 0.6 ml/min for the first 3 min and 0.7 ml for the last 4 min. The chromatographic method separated MPA from its metabolites MPAG and Acyl-MPAG. Mass transitions in negative ionization mode for MPA and the internal standard, indomethacin were m/z: 319-->190.9 and m/z: 356-->312.2, respectively. The assay was linear in the concentration range of 1-1000 microg/l for fMPA with a LLOQ of 1 microg/l and an accuracy of >95%. The two methods reported have an adequate degree of robustness and dynamic concentration range for the measurement of MPA, MPAG and fMPA for therapeutic drug monitoring purposes or pharmacokinetics investigations. PMID:15556544

Patel, Chirag G; Mendonza, Anisha E; Akhlaghi, Fatemeh; Majid, Oneeb; Trull, Andrew K; Lee, Terry; Holt, David W

2004-12-25

91

Analgesic responses to intrathecal morphine in relation to CSF concentrations of morphine-3,?-glucuronide and morphine-6,?-glucuronide  

Microsoft Academic Search

This study was performed to determine whether variations in analgesic responses to intrathecal morphine could be explained by cerebrospinal fluid (CSF) concentrations of morphine metabolites. Twenty-four CSF samples were collected at the beginning, middle and end of treatment periods in seven cancer patients with pain of malignant origin. CSF concentrations of morphine-3,?-glucuronide (M3G) and morphine-6,?-glucuronide (M6G) metabolites were measured by

Gary C. Dennis; Deepa Soni; Ozra Dehkordi; Richard M. Millis; Hutchinson James; William L. West; Robert E. Taylor

1999-01-01

92

Determination of ethyl carbamate in wine by high performance liquid chromatography.  

PubMed

Kinetics of pre-column derivatization with 9-xanthydrol for the determination of ethyl carbamate (EC) in wine by a previous high performance liquid chromatographic method with fluorescence detection was studied and further developed. The life-time of the derivatized product and its excitation/absorption spectra were systematically investigated. Using low acidity (pH=2.5 set by phosphate buffers) only 3% of 9-xanthyl ethyl carbamate (XEC) decomposes in ?48h, allowing a prolonged storage time of the derivatized EC conferring more accurate determination for large sample batches. Detection limit of this method is 3?gL(-1), while its average recovery is 98.5±4.9%. Calibration is linear up to 400?gL(-1). The EC content in 33 Hungarian wine samples ranges from 4.9 to 39.9?gL(-1) (average: 17.7?gL(-1), median: 16.7?gL(-1)), while only three of them was slightly over 30?gL(-1) EC, it being the maximum allowed concentration in countries already having legislation. PMID:23790917

Ajtony, Zsolt; Szoboszlai, Norbert; Bencs, László; Viszket, Erna; Mihucz, Victor G

2013-04-18

93

Determination of acid dissociation constant of degradable tetrabromophenolphthalein ethyl ester by capillary zone electrophoresis.  

PubMed

An acid dissociation constant of tetrabromophenolphthalein ethyl ester (TBPE) was determined through the measurement of electrophoretic mobility by capillary zone electrophoresis (CZE). Although TBPE is degradable in acidic pH region and it gradually degraded at pH conditions around and below its pKa values in the time scale of the CZE measurement, equilibrium species of interest were detected as a peak-shaped signal with tailing of the degraded species. Changes in electrophoretic mobility of the equilibrium species of TBPE were analyzed at its detectable pH range in the presence of phenol red as a mobility standard. An acid dissociation constant of 3.47 ± 0.06 (pK(a), I = 0.01, 25°C, standard error) was determined for TBPE. PMID:23665628

Takayanagi, Toshio; Tabara, Ayumi; Kaneta, Takashi

2013-01-01

94

Simultaneous determination of cortisol, dexamethasone, methylprednisolone, prednisone, prednisolone, mycophenolic acid and mycophenolic acid glucuronide in human plasma utilizing liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

Chronic combination immunosuppressive regimens are commonly prescribed to renal transplant recipients. To develop an assay method for pharmacokinetic studies and therapeutic drug monitoring of multiple immunosuppressives, a liquid chromatography–tandem mass spectrometry (LC\\/MS\\/MS) approach for the simultaneous analysis of several glucocorticoids, mycophenolic acid (MPA) and mycophenolic acid glucuronide (MPAG) was investigated. The resultant method utilized a gradient reverse phase separation over

Robin DiFrancesco; Valerie Frerichs; Julie Donnelly; Colleen Hagler; Jill Hochreiter; Kathleen M. Tornatore

2007-01-01

95

Stereoselective glucuronidation of formoterol by human liver microsomes  

PubMed Central

Aims Formoterol is a ?2-adrenoceptor agonist marketed as a racemic mixture of the active (R; R)- and inactive (S; S)-enantiomers (rac-formoterol). The drug produces prolonged bronchodilation by inhalation but there is significant interpatient variability in duration of effect. Previous work has shown that in humans formoterol is metabolized by conjugation with glucuronic acid but little is known about the stereoselectivity of this reaction. The aim of the present study was to investigate the glucuronidation of formoterol enantiomers in vitro by human liver microsomes. Methods The kinetics of formation of formoterol glucuronides during incubation of racemate and of single formoterol enantiomers with human liver microsomes (n = 9) was characterized by chiral h.p.l.c. assay. Results The kinetics of glucuronidation of the two formoterol enantiomers obeyed the Michaelis-Menten equation. Glucuronidation of formoterol was stereoselective and occurred more than two times faster for (S; S)-formoterol than for (R; R)-formoterol. In incubations with single formoterol enantiomers, the median (n = 9) Km values for (R; R)-glucuronide and (S; S)-glucuronide were 827.6 and 840.4 ?m, respectively, and the median Vmax values were 2625 and 4304 pmol min?1 mg?1, respectively. Corresponding values determined in incubations with rac-formoterol were 357.2 and 312.1 ?m and 1435 and 2086 pmol min?1 mg?1 for (R; R)- and (S; S)-glucuronide, respectively. Interindividual variation was large with the ratio of Vmax/Km (S; S/R; R) ranging from 0.57 to 6.90 for incubations with rac-formoterol. Conclusions Our study demonstrates that glucuronidation of formoterol by human liver microsomes is stereoselective and subject to high interindividual variability. These findings suggest that clearance of formoterol in humans is subject to variable stereoselectivity which could explain the variation in duration of bronchodilation produced by inhaled formoterol in patients with asthma.

Zhang, Mei; Fawcett, J Paul; Kennedy, Julia M; Shaw, John P

2000-01-01

96

Rapid gas chromatographic method for determining ethyl carbamate in alcoholic beverages with thermal energy analyzer detection.  

PubMed

A rapid column elution method has been developed for the determination of ethyl carbamate (EC) in alcoholic beverages. The beverage is mixed with Celite and packed in a column containing deactivated alumina capped with a layer of sodium sulfate. EC is then eluted with methylene chloride. The method, using a gas chromatograph-thermal energy analyzer with a nitrogen converter for detection and quantitation of EC, has been applied to a variety of alcoholic beverages. Recoveries +/- standard deviations of EC in wine and whisky fortified at the 20 and 133 micrograms/kg (ppb) levels averaged 87.3 +/- 5.3 and 88.7 +/- 3.6%, respectively. The method has a limit of detection of 1.5 ppb. Gas chromatography/mass spectrometry/mass spectrometry was used to confirm the identity and quantitation of EC in selected beverage extracts. PMID:3391950

Canas, B J; Havery, D C; Joe, F L

97

Gas Chromatographic Method for the Determination of Residual Monomers, 2-(Acryloyloxy)ethyl Isocyanate and 2-(Methacryloyloxy)ethyl Isocyanate, as Curing Agents in an Ultraviolet Curable Adhesive.  

PubMed

A gas chromatographic method is described for the determination of residual 2-(acryloyloxy)ethyl isocyanate (AOI) and 2-(methacryloyloxy)ethyl isocyanate (MOI) as curing agents in an ultraviolet curable adhesive. Pre-column derivatization was employed in the determination of AOI and MOI as a means of enhancing the response of the flame ionization detector. Urethane derivatives of AOI and MOI were derived using methanol for 30 min at room temperature. The accuracies (n = 5, three concentration levels) were in the range of 113.4 to 126.7%, and precisions (n = 5, three concentration levels) were in the range of 0.8 to 4.3% for AOI-OMe. Furthermore, the accuracies were in the range of 79.5 to 108.6% and the precisions were in the range of 1.0 to 2.4% for MOI-OMe. The correlation coefficients of six calibration standards were all greater than 0.9999 for AOI-OMe and greater than 0.9998 for MOI-OMe over the range from 10 to 100 µg/mL. PMID:23357043

Kim, Byoung-Hyoun; Kim, Nosun; Moon, Dong Cheul

2013-01-27

98

Ultrasound-assisted emulsification-microextraction for the sensitive determination of ethyl carbamate in alcoholic beverages.  

PubMed

A method based on ultrasound-assisted emulsification-microextraction (USAEME) was proposed in this contribution for the determination of ethyl carbamate (EC) in alcoholic beverages using gas chromatography coupled to triple quadrupole mass spectrometry. To achieve the determination of EC in alcoholic beverages, the influences on the extraction efficiency of type and volume of extraction solvent, temperature, ionic strength, alcohol content, and extraction time were studied, once the extraction solvent had been selected. The optimized conditions were 200.0 ?L of chloroform at 30 °C during 5 min with 15% (m/v) sodium chloride addition. The detection limit, relative standard deviations, linear range, and recoveries under the optimized conditions were 0.03 ?g L(-1), 4.2-6.1%, 0.1-50.0 ?g L(-1), and 80.5-87.9%, respectively. Moreover, the feasibility of the present method was also validated by real samples. To the best of our knowledge, this is the first time that USAEME has been applied to determine a strongly hydrophilic compound in alcoholic beverages. PMID:23820951

Liao, Qie Gen; Li, Wei Hong; Luo, Lin Guang

2013-07-03

99

Determination of impurities in flame retardant monomer 2-carboxyl ethyl(phenyl) phosphinic acid by ion chromotography  

Microsoft Academic Search

In this paper, a method based on ion chromatography (IC) with conductivity detector was developed for the determination of impurities including phenyl phosphinic acid (BPA), phenyl phosphonic acid (PPOA) and crylic acid in flame retardant monomer 2-carboxyl ethyl(phenyl) phosphinic acid (CEPPA). Under favorable chromatographic conditions, good linear relationship, sensitivity and reproducibility were obtained. Detection limits of BPA, PPOA and crylic

Mei-Lan Chen; Wei Yan; Yongxin Chen; Zhishen Jia; Yan Zhu

2007-01-01

100

Determination of butyl- and phenyltin compounds in sediments by GC-FPD after NaBEt 4 ethylation  

Microsoft Academic Search

A reliable and rapid speciation method for the simultaneous determination of butyl- and phenyltin species in sediment samples has been developed. Two extraction procedures are compared: methanolic hydrochloric acid (at four different concentrations) and ethanoic acid leaching. Derivatization is carried out by the one-step ethylation\\/extraction procedure using the sodium tetraethylborate reagent directly in aqueous phase in the presence of an

C. Carlier-Pinasseau; G. Lespes; M. Astruc

1997-01-01

101

High-Performance Liquid Chromatographic Determination of Triptonide, Triptriolide, and Triptophenolide in Ethyl Acetate Extract of Tripterygium Wilfordii Hook F  

Microsoft Academic Search

To monitor the composition of extracts of the Chinese herbal remedy Tripterygium wilfordii Hook F (TwHF), a rapid, selective, and sensitive reverse phase HPLC method was developed for the quantitative determination of some of the major or active diterpenoid components, triptonide (1), triptophenolide (2), and triptriolide (3). Ethyl acetate extracts of TwHF were extracted with chloroform, filtered, and then purified

Yanping Mao; John J. Cai; Xuelian Tao; Li Ma; Peter E. Lipsky

1998-01-01

102

78 FR 9938 - Ethyl Alcohol for Fuel Use: Determination of the Base Quantity of Imports  

Federal Register 2010, 2011, 2012, 2013

...establish the ``base quantity'' of imports of fuel ethyl alcohol, and the Commission transmitted...in the further administration of the law. Section 423(g...Counsel at (202) 205-3091. The media should contact Margaret...

2013-02-12

103

Development of an enzyme-linked immunosorbent assay for quantitative determination of quizalofop-p-ethyl.  

PubMed

Accurate quantification of quizalofop-p-ethyl is essential for it may do harm to humans and animals through both water and food. Currently, detection of quizalofop-p-ethyl mainly relies on methods such as gas chromatography, high performance liquid chromatography, and gas chromatography-mass spectrometry. Although these techniques are reliable, they are relatively expensive and time-consuming because of multistep sample cleanup. To address this, we developed a competitive indirect enzyme-linked immunosorbent assay (ciELISA) with a polyclonal antibody against quizalofop-p-ethyl that was generated in our lab. The IC(50) of detection was 0.03495 microg/mL, and the lowest detection limit reached 0.00192 microg/mL. Furthermore, the method had high specificity for it did not cross-react with other structure-related compounds. When water and soil samples that were fortified with quizalofop-p-ethyl were analyzed by this ELISA, recoveries were in the range of 89-110% from water and 81-108% from soil. Good correlations between this immunoassay and gas chromatography data were obtained for residues of quizalofop-p-ethyl in water and soil. Our data indicate that this method is a convenient analytical technique for monitoring quizalofop-p-ethyl in waters without extraction and the extra cleanup step and in soil without the cleanup step. PMID:17090107

Zeng, Deyi; Shi, Haiyan; Li, Bo; Wang, Minghua; Song, Baoan

2006-11-15

104

Determination of ethyl carbamate in cachaça produced from copper stills by HPLC.  

PubMed

Ethyl carbamate (EC) is a common substance in fermented foods and drinks, and its quantification is important because of its carcinogenic nature and its usually presence in alcoholic beverages. The present work involved the development and validation of an analytical method for the evaluation of EC in cachaça by HPLC-FLD after previous derivatization with xanthydrol. The method presented a mean recovery of 94.88%, an intra-day precision of 4.19% (30.0 ?gL(-1)) and 3.32% (75.0 ?gL(-1)), a coefficient of determination (r(2)) equal to 0.9985, and limits of detection and quantification equal to 6.39 and 21.32 ?gL(-1), respectively. The results show that the analytical method is accurate, reproducible and linear over the concentration range from 5.0 to 160 ?g of EC per litre. The method was applied to the analysis of EC in cachaça, the analyses being rapid and efficient. PMID:23411237

de Resende Machado, Ana Maria; Cardoso, M das Graças; Saczk, Adelir Aparecida; dos Anjos, Jeancarlo Pereira; Zacaroni, Lidiany Mendonça; Dórea, Haroldo Silveira; Nelson, David Lee

2012-11-29

105

Determination of volatile fatty acid ethyl esters in raw spirits using solid phase microextraction and gas chromatography  

Microsoft Academic Search

An analytical method for the determination of fatty acid ethyl esters in raw spirits of different quality or produced from various raw materials has been developed and optimized. A combination of headspace solid phase microextraction (HS-SPME) as the extraction technique and gas chromatography with flame ionization detection (GC-FID) as the determination technique was utilized. HS-SPME conditions such as: type of

Beata Plutowska; Waldemar Wardencki

2008-01-01

106

Validated LC-MS/MS method for the determination of 3-hydroxflavone and its glucuronide in blood and bioequivalent buffers: application to pharmacokinetic, absorption, and metabolism studies.  

PubMed

The purpose of this study is to develop an UPLC-MS/MS method to quantify 3-hydroxyflavone (3-HF) and its metabolite, 3-hydroxyflavone-glucuronide (3-HFG) from biological samples. A Waters BEH C8 column was used with acetonitrile/0.1% formic acid in water as mobile phases. The mass analysis was performed in an API 5500 Qtrap mass spectrometer via multiple reaction monitoring (MRM) with positive scan mood. The one-step protein precipitation by acetonitrile was used to extract the analytes from blood. The results showed that the linear response range was 0.61-2500.00 nM for 3-HF and 0.31-2500.00 nM for 3-HFG. The intra-day variance is less than 16.5% and accuracy is in 77.7-90.6% for 3-HF and variance less than 15.9%, accuracy in 85.1-114.7% for 3-HFG. The inter-day variance is less than 20.2%, accuracy is in 110.6-114.2% for 3-HF and variance less than 15.6%, accuracy in 83.0-89.4% for 3-HFG. The analysis was done within 4.0 min. Only 10 ?l of blood is needed due to the high sensitivity of this method. The validated method was successfully used to pharmacokinetic study in A/J mouse, transport study in the Caco-2 cell culture model, and glucuronidation study using mice liver and intestine microsomes. The applications revealed that this method can be used for 3-HF and 3-HFG analysis in blood as well as in bioequivalent buffers such HBSS and KPI. PMID:23973631

Xu, Beibei; Yang, Guanyi; Ge, Shufan; Yin, Taijun; Hu, Ming; Gao, Song

2013-08-05

107

Determination of coumarin, vanillin, and ethyl vanillin in vanilla extract products: liquid chromatography mass spectrometry method development and validation studies  

Microsoft Academic Search

A LC–MS method was developed for the determination of coumarin, vanillin, and ethyl vanillin in vanilla products. Samples were analyzed using LC–electrospray ionization (ESI)–MS in the positive ionization mode. Limits of detection for the method ranged from 0.051 to 0.073?gmL?1. Using the optimized method, 24 vanilla products were analyzed. All samples tested negative for coumarin. Concentrations ranged from 0.38 to

Lowri S. de Jager; Gracia A. Perfetti; Gregory W. Diachenko

2007-01-01

108

High Performance Liquid Chromatographic Determination of Triptolide and Tripdiolide in an Ethyl Acetate Extract of Tripterygium wilfordii Hook F  

Microsoft Academic Search

A new analytical method for the determination of triptolide and tripdiolide in ethyl acetate extracts of Triterygium wilfordii Hook F. is described. The procedure consists of preliminary enrichment by Sep-Pak alumina B cartridge chromatography followed by HPLC analysis. HPLC is performed with a stainless steel column packed with Nova-Pak C18, using acetonitrile-water (19 : 81) as a mobile phase for

John J. Cai; Xuelian Tao; Peter E. Lipsky

1994-01-01

109

Use of the 'Markham' Semi-Micro Still for the Determination of Stabilisers in Propellants. Part 1. Determination of Ethyl Centralite at the 3-8% Level.  

National Technical Information Service (NTIS)

The use of the 'Markham' semi-micro still in the determination of ethyl centralite in propellants is described. The new procedure gives results which compare well with those from the traditional steam distillation-gravimetric method, so that continuity ca...

R. G. Davidson

1977-01-01

110

Scintigraphic imaging with a peptide glucuronide in rabbits: 99mTc exorphin C glucuronide  

Microsoft Academic Search

A peptide glucuronide (Exorphin C glucuronide) was labeled with 99mTc using glucoheptonate (GH) as a bifunctional chelating agent. Scintigraphic imaging was performed in male Albino rabbits. Exorphin C glucuronide showed rapid and efficient labeling with 99mTc using glucoheptonate as a bifunctional chelate. Results demonstrated that 99mTc-GEG may be a useful new type of glucuronide derivative of peptides for diagnosis of

T. Ertay; P. Ünak; F. Z. Biber; C. Tasc?; F. Zihnio?lu; H. Durak

2007-01-01

111

Correlation between 1 H NMR and traditional methods for determining lipid oxidation of ethyl docosahexaenoate  

Microsoft Academic Search

Lipid oxidation includes a complex set of chemical reactions; and no single analytical method is available to give a satisfactory\\u000a description of lipid oxidation status. High-resolution NMR spectroscopy techniques were tested to establish possible correlations\\u000a with traditional analytical methods and to study lipid oxidation products. Ethyl esters of all-cis 4,7,10,13,16,19-docosahexaenoic acid (DHA) (22?6n?3), with and without added ?-tocopherol, were oxidized

Eva Falch; Henrik W. Anthonsen; David E. Axelson; Marit Aursand

2004-01-01

112

Enhanced clearance of topoisomerase I inhibitors from human colon cancer cells by glucuronidation.  

PubMed

As part of a program to identify novel mechanisms of resistance to topoisomerase I (topo I) inhibitors, the cellular pharmacology of 7-ethyl-10-hydroxycamptothecin (SN-38), the active metabolite of clinically used irinotecan (CPT-11) and NU/ICRF 505, an anthraquinone-tyrosine conjugate, has been investigated in two human colorectal cancer (CRC) cell lines. Two novel metabolites of NU/ICRF 505 (M1 and M2) and a single metabolite of SN-38 (M1) were detected by high performance liquid chromatography in the culture medium of HT29 cells but were absent in HCT116 cells. Identities of all three metabolites were established by a combination of biochemical and physicochemical techniques. M1 of SN-38 was the C10-(beta)-glucuronide of the parent lactone while M1 of NU/ICRF 505 was the C4-O-glucuronide and M2 the tyrosine-O-glucuronide, both of the parent compound. Drug transport studies revealed that by 24hr HT29 cells had effectively cleared 82.5% of NU/ICRF 505 (10 microM) into the culture medium as the two glucuronides. In contrast, intracellular concentrations of NU/ICRF 505 were maintained in HCT116 cells in the absence of glucuronidation at a level 550 times greater than in HT29 cells. HT29 cells cleared 40.9% of SN-38 (1 microM) as the glucuronide to the culture medium, while the parent drug was maintained at a level 2-fold greater in HCT116 cells. Enhanced drug clearance due to glucuronidation may contribute to intrinsic drug resistance of human CRC. PMID:11992628

Cummings, Jeffrey; Boyd, Gary; Ethell, Brian T; Macpherson, Janet S; Burchell, Brian; Smyth, John F; Jodrell, Duncan I

2002-02-15

113

Simultaneous determination of mercury speciation in biological materials by GC/CVAFS after ethylation and room-temperature precollection.  

PubMed

We developed a method for the simultaneous determination of monomethyl mercury (MMHg), inorganic mercury [Hg(II)], and total mercury (THg) in biological materials. A variety of biological materials can be digested in methanolic KOH solution. The MMHg and Hg(II) present are converted to volatile ethyl derivatives, methylethyl mercury and diethyl mercury, by an aqueous-phase ethylation reaction with sodium tetraethylborate. The ethyl derivatives are precollected onto a trapping column at room temperature, in case of disconnection with the separation/detection system, and then thermally desorbed into a packed isothermal gas chromatography (GC) column. Eluted organo-Hg compounds from the GC column are decomposed into Hg0, and detection is completed by cold vapor atomic fluorescence spectrometry (CVAFS). Pure standard solutions can be used for calibration. The sum of MMHg and Hg(II) obtained by this method equals the THg value obtained by digestion with HNO3 and H2SO4, reduction with SnCl2, and single-stage amalgamation/CVAFS for all biological materials studied. Absolute detection limits are 0.6 pg and 1.3 pg of Hg as MMHg and Hg(II), respectively, corresponding to 0.3 ng and 0.6 ng/g (wet) of sample. PMID:8149617

Liang, L; Bloom, N S; Horvat, M

1994-04-01

114

Phenotype-genotype correlation of in vitro SN38 (active metabolite of irinotecan) and bilirubin glucuronidation in human liver tissue with UGT1A1 promoter polymorphism  

Microsoft Academic Search

Background: Hepatic uridine diphosphate glucuronosyltransferase (UGT) isoform 1A1 (UGT1A1) is primarily responsible for the glucuronidation of SN-38 (7-ethyl-10-hydroxycamptothecin), the active metabolite of the anticancer agent irinotecan. UGT1A1, also catalyzing the glucuronidation of bilirubin, has been shown to have reduced activity in Gilbert's syndrome. The presence of an additional TA repeat [(TA)7 TAA] in the TATA sequence of UGT1A1 has been

Lalitha Iyer; Diana Hall; Soma Das; Melissa A. Mortell; Jacqueline Ramírez; Sarang Kim; Anna Di Rienzo; Mark J. Ratain

1999-01-01

115

Stereoselective glucuronidation of carvedilol by Chinese liver microsomes*  

PubMed Central

Objective: To study the stereoselective glucuronidation of carvedilol (CARV) by three Chinese liver microsomes. Methods: The metabolites of CARV were identified by a hydrolysis reaction with ?-glucuronidase and HPLC-MS/MS. The enzyme kinetics for CARV enantiomers glucuronidation was determined by a reversed phase-high pressure liquid chromatography (RP-HPLC) assay using (S)-propafenone as internal standard after precolumn derivatization with 2,3,4,6-tetra-O-acetyl-?-D-glucopyranosylisothiocyanate. Results: Two CARV glucuronides were found in three Chinese liver microsomes incubated with CARV. The non-linear regression analysis showed that the values of K m and V max for (S)-CARV and (R)-CARV enantiomers were (118±44) µmol/L, (2 500±833) pmol/(min·mg protein) and (24±7) µmol/L, (953±399) pmol/(min·mg protein), respectively. Conclusion: These results suggested that there was a significant (P<0.05) stereoselective glucuronidation of CARV enantiomers in three Chinese liver microsomes, which might partly explain the enantioselective pharmacokinetics of CARV.

You, Lin-ya; Yu, Chun-na; Xie, Sheng-gu; Chen, Shu-qing; Zeng, Su

2007-01-01

116

Dietary green and white teas suppress UDP-glucuronosyltransferase UGT2B17 mediated testosterone glucuronidation.  

PubMed

The anabolic steroid testosterone can be used by athletes to enhance athletic performance and muscle growth. UDP-glucuronosyltransferase (UGT2B17) is the key enzyme involved in the glucuronidation of testosterone to testosterone glucuronide, which also serves as a marker for the testosterone/epitestosterone (T/E) ratio used to detect testosterone abuse in sport. Inhibitors of testosterone glucuronidation could have an impact on circulating testosterone levels, thus aiding performance, as well as potentially affecting the urinary T/E ratio and therefore masking testosterone abuse. Previous reports have revealed that non-steroidal, anti-inflammatory drugs, diclofenac and ibuprofen, inhibit the UGT2B17 enzyme. The aim of this study is to analyse dietary tea samples for inhibition of testosterone glucuronidation and, where inhibition is present, to identify the active compounds. Analysis of testosterone glucuronidation was conducted by performing UGT2B17 assays with detection of un-glucuronidated testosterone using high performance liquid chromatography. The results from this study showed that testosterone glucuronidation was inhibited by the green and white tea extracts, along with specific catechin compounds, notably: epicatechin, epigallocatechin gallate (EGCG) and catechin gallate. The IC50 inhibition value for EGCG was determined, using a Dixon plot, to be 64 ?M, equalling the most active NSAID inhibitor diclofenac. Thus, common foodstuffs and their constituents, for the first time, have been identified as inhibitors of a key enzyme involved in testosterone glucuronidation. Whilst these common compounds are not substrates of the UGT2B17 enzyme, we showed that they inhibit testosterone glucuronidation which may have implications on current doping control in sport. PMID:22429924

Jenkinson, Carl; Petroczi, Andrea; Barker, James; Naughton, Declan P

2012-03-11

117

Gas chromatographic procedures for determination of ethanol in postmortem blood using t-butanol and methyl ethyl ketone as internal standards  

Microsoft Academic Search

Three gas chromatographic procedures for the determination of ethanol in postmortem blood using alternative internal standards to n-propanol are presented: a direct injection procedure using t-butanol, and two headspace methods using t-butanol and methyl ethyl ketone. t-Butanol and methyl ethyl ketone were well resolved from ethanol, acetone, methanol and other commonly observed putrefactive volatiles using direct injection or headspace analysis.

Carol L. O'Neal; Carl E. Wolf; Barry Levine; Gary Kunsman; Alphonse Poklis

1996-01-01

118

Microstructure determination of 2-hydroxy ethyl methacrylate and methyl acrylate copolymers by NMR spectroscopy  

NASA Astrophysics Data System (ADS)

Copolymers of 2-Hydroxy ethyl methacrylate and methyl acrylate (H/M) of different compositions were synthesized by free radical bulk polymerization using azobisisobutyronitrile (AIBN) as an initiator under nitrogen atmosphere. The copolymers compositions were calculated from 1H NMR spectra. The reactivity ratios for H/M copolymers obtained from a linear Kelen Tudos method (KT) and nonlinear error-in-variables method (EVM) are rH = 3.31 ± 0.08, rM = 0.23 ± 0.00 and rH = 3.32, rM = 0.23, respectively. The complete spectral assignment of methine, methylene, methyl and carbonyl carbon regions in terms of compositional and configurational sequences of H/M copolymers was done with the help of 13C{1H} NMR, distortionless enhancement by polarization transfer (DEPT), two-dimensional heteronuclear single quantum coherence (HSQC) along with total correlated spectroscopy (TOCSY). Further, the assignments of carbonyl region were made with the help of heteronuclear multiple bond coherence (HMBC) spectrum.

Brar, A. S.; Hooda, Sunita; Goyal, Ashok Kumar

2007-02-01

119

UGT2B10 genotype influences nicotine glucuronidation, oxidation and consumption  

PubMed Central

Background Tobacco exposure is routinely assessed by quantifying nicotine metabolites in plasma or urine. On average, 80% of nicotine undergoes C-oxidation to cotinine. However, interindividual variation in nicotine glucuronidation is substantial and glucuronidation accounts for from 0 to 40% of total nicotine metabolism. We report here the effect of a polymorphism in a UDP-glucuronsyl transferase, UGT2B10, on nicotine metabolism and consumption. Methods Nicotine, cotinine, their N-glucuronide conjugates, and total trans-3'-hydroxycotinine were quantified in the urine (n=327) and plasma (n =115) of smokers. Urinary nicotine N-oxide was quantified in 105 smokers. Nicotine equivalents, the sum of nicotine and all major metabolites, were calculated for each smoker. The relationship of the UGT2B10 Asp67Tyr allele to nicotine equivalents, N-glucuronidation, and C-oxidation was determined. Results Individuals heterozygous for the Asp67Tyr allele excreted less nicotine or cotinine as their glucuronide conjugates than wild-type, resulting in a 60% lower ratio of cotinine glucuronide:cotinine, a 50% lower ratio of nicotine glucuronide:nicotine and increased cotinine and trans-3'-hydroxycotinine. Nicotine equivalents, a robust biomarker of nicotine intake, were lower among Asp67Tyr heterozygotes compared to individuals without this allele; 58.2 nmol/ml (95% CI, 48.9 – 68.2) versus 69.2 nmol/ml (95% CI, 64.3 – 74.5). Conclusions Individuals heterozygous for UGT2B10 Asp67Tyr consume less nicotine than do wild type smokers. This striking observation suggests that variations in nicotine N-glucuronidation, as reported for nicotine C-oxidation, may influence smoking behavior. Impact UGT2B10 genotype influences nicotine metabolism and should be taken into account when characterizing the role of nicotine metabolism on smoking.

Berg, Jeannette Zinggeler; von Weymarn, Linda; Thompson, Elizabeth A.; Wickham, Katherine M.; Weisensel, Natalie A.; Hatsukami, Dorothy K.; Murphy, Sharon E.

2010-01-01

120

Determination of impurities in flame retardant monomer 2-carboxyl ethyl(phenyl) phosphinic acid by ion chromotography.  

PubMed

In this paper, a method based on ion chromatography (IC) with conductivity detector was developed for the determination of impurities including phenyl phosphinic acid (BPA), phenyl phosphonic acid (PPOA) and crylic acid in flame retardant monomer 2-carboxyl ethyl(phenyl) phosphinic acid (CEPPA). Under favorable chromatographic conditions, good linear relationship, sensitivity and reproducibility were obtained. Detection limits of BPA, PPOA and crylic acid were 1.5, 0.5, 0.4 microg l(-1), respectively. Relative standard deviations (RSD) of repeated analyses were less than 2.22% (n=10). The real samples (white crystal) have been tested and rate of recovery were 89-108%. It was confirmed that this method could be used in the analysis of flame retardant monomers. PMID:17349648

Chen, Mei-Lan; Yan, Wei; Chen, Yongxin; Jia, Zhishen; Zhu, Yan

2007-02-20

121

Determination of butyl- and phenyltin compounds in sediments by GC-FPD after NaBEt(4) ethylation.  

PubMed

A reliable and rapid speciation method for the simultaneous determination of butyl- and phenyltin species in sediment samples has been developed. Two extraction procedures are compared: methanolic hydrochloric acid (at four different concentrations) and ethanoic acid leaching. Derivatization is carried out by the one-step ethylation/extraction procedure using the sodium tetraethylborate reagent directly in aqueous phase in the presence of an isooctane layer. Analysis is performed by capillary gas chromatography hyphenated to flame photometric detection (GC-FPD). Detection limits range from 0.5 to 1.5 ng(Sn) g(-1)(dry weight). Analysis of environmental samples and certified reference materials demonstrate the accuracy of the analytical method. PMID:18966851

Carlier-Pinasseau, C; Lespes, G; Astruc, M

1997-07-01

122

Position preference on glucuronidation of mono-hydroxylflavones in human intestine.  

PubMed

Extensive intestinal glucuronidation has been previously reported in both human and animals after oral administration of naturally occurred flavonoids. The present study aims to investigate the relationship between human intestinal glucuronidation activity and the position of hydroxyl substitution on flavonoids. Seven commercially available mono-hydroxyflavones (HF), namely 3-, 5-, 6-, 7-, 2'-, 3'- and 4'-mono-hydroxyflavones, were chosen as model compounds. Glucuronidation activity of the selected seven HFs was investigated by incubating each HF at various concentrations with human jejunum S9 at 37 degrees C for 10 min. The generated glucuronides were identified by HPLC/MS and quantified by HPLC/UV. Metabolic kinetics parameters including Km and Vmax of each HF were determined. The results demonstrated that the glucuronidation activity of 6- and 3'-mono-hydroxyflavones was much greater than that of 3-, 4'-, 7- and 2'-HF with 5-HF to be the lowest. The findings imply that nucleophilicity and stereo-conformation of OH substituents are crucial for the intestinal glucuronidation of flavonoids. PMID:16376382

Zhang, Li; Lin, Ge; Zuo, Zhong

2005-12-22

123

Urine tested positive for ethyl glucuronide and ethyl sulfate after the consumption of yeast and sugar  

Microsoft Academic Search

BackgroundTo an increasing degree, EtG and EtS are routinely used for the proof of abstinence for purposes of traffic, occupational, addiction and social medicine. This routine use demands further investigations on the sensitivity and specificity of these analytes and the examination of possible genesis of positive EtG and EtS concentrations even without the consumption of ethanol. In vivo fermentation with

Annette Thierauf; Ariane Wohlfarth; Volker Auwärter; Markus Große Perdekamp; Friedrich Martin Wurst; Wolfgang Weinmann

2010-01-01

124

High-sensitivity analysis of buprenorphine, norbuprenorphine, buprenorphine glucuronide, and norbuprenorphine glucuronide in plasma and urine by liquid chromatography-mass spectrometry.  

PubMed

A new method using ultra-fast liquid chromatography and tandem mass spectrometry (UFLC-MS/MS) was developed for the simultaneous determination of buprenorphine and the metabolites norbuprenorphine, buprenorphine-3?-glucuronide, and norbuprenorphine-3?-glucuronide in plasma and urine. Sample handling, sample preparation and solid-phase extraction procedures were optimized for maximum analyte recovery. All four analytes of interest were quantified by positive ion electrospray ionization tandem mass spectrometry after solid-phase microextraction. The lower limits of quantification in plasma were 1pg/mL for buprenorphine and buprenorphine glucuronide, and 10pg/mL for norbuprenorphine and norbuprenorphine glucuronide. The lower limits of quantitation in urine were 10pg/mL for buprenorphine, norbuprenorphine and their glucuronides. Overall extraction recoveries ranged from 68-100% in both matrices. Interassay precision and accuracy was within 10% for all four analytes in plasma and within 15% in urine. The method was applicable to pharmacokinetic studies of low-dose buprenorphine. PMID:24095872

Regina, Karen J; Kharasch, Evan D

2013-09-08

125

Simultaneous quantification of buprenorphine, norbuprenorphine, buprenorphine glucuronide, and norbuprenorphine glucuronide in human placenta by liquid chromatography mass spectrometry  

PubMed Central

A LCMS method was developed and validated for the determination of buprenorphine (BUP), norbuprenorphine (NBUP), buprenorphine glucuronide (BUP-Gluc), and norbuprenorphine glucuronide (NBUP-Gluc) in placenta. Quantification was achieved by selected ion monitoring of m/z 468.4 (BUP), 414.3 (NBUP), 644.4 (BUP-Gluc), and 590 (NBUP-Gluc). BUP and NBUP were identified monitoring MS2 fragments m/z 396, 414 and 426 for BUP, and 340, 364 and 382 for NBUP, and glucuronide conjugates monitoring MS3 fragments m/z 396 and 414 for BUP-Gluc, and 340 and 382 for NBUP-Gluc. Linearity was 1–50 ng/g. Intra-day, inter-day and total assay imprecision (% RSD) were <13.4%, and analytical recoveries were 96.2–113.1%. Extraction efficiencies ranged from 40.7–68%, process efficiencies 38.8–70.5%, and matrix effect 1.3–15.4%. Limits of detection were 0.8 ng/g for all compounds. An authentic placenta from an opioid-dependent pregnant woman receiving BUP pharmacotherapy was analyzed. BUP was not detected but metabolite concentrations were NBUP-Gluc 46.6, NBUP 15.7 and BUP-Gluc 3.2 ng/g.

Concheiro-Guisan, Marta; Shakleya, Diaa M.; Huestis, Marilyn A.

2011-01-01

126

N-Glucuronidation of the antiepileptic drug retigabine: results from studies with human volunteers, heterologously expressed human UGTs, human liver, kidney, and liver microsomal membranes of Crigler-Najjar type II  

Microsoft Academic Search

Retigabine (D-23129), an N-2-amino-4-(4-fluorobenzylamino)phenylcarbamine acid ethyl ester, is a novel antiepileptic drug which is currently in phase II clinical development. This drug undergoes N-glucuronidation. We aimed to identify the principal enzymes involved in the N-glucuronidation pathway of retigabine and compared our findings with those obtained from human liver (a pool of 30 donors) and kidney microsomes (a pool of 3

Jürgen Borlak; Antje Gasparic; Mathias Locher; Hubert Schupke; Robert Hermann

2006-01-01

127

Microsomal hydroxylation and glucuronidation of [6]-gingerol.  

PubMed

[6]-Gingerol is the major pungent principle of ginger and frequently is ingested with various condiments and nutritional supplements. We report here that incubation of [6]-gingerol with NADPH-fortified rat hepatic microsomes gave rise to eight metabolites, which were tentatively identified by GC-MS analysis as two products of aromatic hydroxylation as well as the diastereomers of two aliphatic hydroxylation products and the diastereomers of [6]-gingerdiol. Hepatic microsomes from rats and humans fortified with UDPGA glucuronidated [6]-gingerol predominantly at the phenolic hydroxyl group, but small amounts of a second monoglucuronide involving the aliphatic hydroxyl group were also identified by LC-MS/MS analysis. Human intestinal microsomes formed the phenolic glucuronide only. Supersomes containing human UGT1A1 and 1A3 exclusively generated the phenolic glucuronide, albeit with very low activities, whereas UGT1A9 catalyzed the specific formation of the alcoholic glucuronide and UGT2B7 the predominant formation of the phenolic glucuronide with high activities. Our study indicates a rather complex metabolism of [6]-gingerol, which should be taken into consideration for the multiple biological activities of this compound. PMID:17090120

Pfeiffer, Erika; Heuschmid, Franziska F; Kranz, Stefan; Metzler, Manfred

2006-11-15

128

[Determination of organotin compounds in plastic products by GC/MS after ethyl derivatization with sodium tetraethylborate].  

PubMed

A simultaneous determination method for 9 organotin compounds in polyvinyl chloride (PVC) and silicone products used as kitchen utensils and food packages was developed using ethyl derivatization with sodium tetraethylborate (NaBEt4). Organotin compounds were extracted with acetone-hexane (3:7) from the samples after acidification and the extract was filtered and concentrated at under 40 degrees C. After centrifugal separation, these compounds were derivatized with 2% NaBEt4 solution and determined by GC/MS. This method was applicable for simple routine analysis. Recoveries of spiked compounds were 49.1-118.1% for 3 PVC products and 88.8-102.2% for a siliconized paper. Monooctyltin, dioctyltin and trioctyltin compounds were found in all PVC food containers at the levels of 123-1,380 micrograms/g, 1,770-13,200 micrograms/g and 6.6-139 micrograms/g, respectively. They also were found in 3 gloves, 5 spouts, 1 hose and 5 pipes. Some PVC products contained monomethyltin, dimethyltin, trimethyltin, monobutyltin and dibutyltin compounds at the levels of 97.3-433 micrograms/g, 96.5-5,120 micrograms/g, 8.5-24.9 micrograms/g, 1.2-852 micrograms/g and 1.2-29.4 micrograms/g, respectively. PMID:12436712

Ohno, Hiroyuki; Suzuki, Masako; Nakashima, Shigehito; Aoyama, Taiki; Mitani, Kazunori

2002-08-01

129

Analysis of catechol-type glucuronides in urine samples by liquid chromatography–electrospray ionization-tandem mass spectrometry  

Microsoft Academic Search

A direct and fast liquid chromatographic–electrospray ionization-tandem mass spectrometric (LC–ESI-MS–MS) method is described for the determination of 3-O-glucuronides of E- and Z-entacapone, nitecapone and tolcapone and 1-O- and 2-O-glucuronides of 4-nitrocatechol in urine. p-Nitrophenyl ?-d-glucuronide was used as internal standard. Spiked urine samples were prepared by solid-phase extraction and analysed by isocratic LC–ESI-MS–MS in negative ion mode. The ESI mass

Helena Keski-Hynnilä; Riitta Andersin; Leena Luukkanen; Jyrki Taskinen; Risto Kostiainen

1998-01-01

130

Glucuronides from metabolites to medicines: a survey of the in vivo generation, chemical synthesis and properties of glucuronides.  

PubMed

Covering: 1998 to 2011. Previous review: Nat. Prod. Rep., 1998, 15, 173-186. The fourteen years that have passed since the previous review on this topic have seen a significant increase of interest in many aspects of glucuronide chemistry and biology. Glucuronides are the most important class of phase 2 xenobiotic metabolites and typically act in a detoxifying role. While this is generally true for O-alkyl and O-aryl glucuronides, a number of glucuronides are known to be pharmacologically active per se. Additionally the use of glucuronide prodrugs, notably to ameliorate the cytotoxicity of anticancer agents, has markedly increased. Whereas the previous review covered only the synthesis of O-glucuronides, we now include N-, S- and C-glucuronides also and discuss both synthetic and biological aspects. Synthetic methods for all classes of glucuronides are reviewed and updated, together with advances in the enzymatic synthesis of glucuronides and methods for their detection. Finally we discuss the biological reactivity of glucuronides where known, including the important morphine-6-glucuronide. A lively debate has continued for several years on whether O-acyl glucuronide metabolites of carboxylic acids are toxic, affecting both the safety assessment of well-used drugs and new drug development programmes. We summarise the current understanding, together with other known examples of interaction between glucuronides and macromolecules. PMID:23648894

Stachulski, Andrew V; Meng, Xiaoli

2013-06-01

131

Inhibition of ciramadol glucuronidation by benzodiazepines.  

PubMed

Studies on the inhibition of ciramadol glucuronidation by benzodiazepines were performed in vitro and in vivo. Ciramadol glucuronidation was slower (Vmax, 1.56 vs. 5.40 nmol/min/mg of microsomal protein) in human than in dog liver microsomes. Inhibition constants (Ki) for lorazepam and oxazepam were 3 to 4 times higher than that calculated for diazepam. Rates of morphine glucuronidation in human liver microsomes were assessed for comparative purposes and agreed with literature values. Each benzodiazepine appeared to be a competitive inhibitor of ciramadol and morphine UDP-glucuronyltransferase activity. The in vivo disposition of ciramadol was unchanged in dogs pretreated with lorazepam. After diazepam treatment no change in the Vdss of ciramadol occurred, but plasma clearance was significantly reduced, resulting in a prolongation of t1/2. Diazepam caused a significant reduction in the oral clearance of ciramadol, whereas no change occurred in systemic availability. Thus, diazepam may have had a secondary effect on hepatic blood flow (QH) and produced offsetting alterations in both intrinsic clearance (Cl int) and QH. A decrease in the area under the plasma concentration time curves of ciramadol aryl O-glucuronide following iv treatment with diazepam coupled with the in vitro data indicate that the mechanism for the decrease in the clearance of ciramadol is inhibition of its glucuronidation by diazepam. Since glucuronidation plays a major role in the elimination of ciramadol in man and dog, these experiments suggest that the disposition of ciramadol in man would not be affected by coadministration of lorazepam, whereas the potential for a diazepam/ciramadol drug interaction in humans exists. PMID:2873990

Meacham, R H; Sisenwine, S F; Liu, A L; Kick, C J; Barinov, I; Ruelius, H W

132

The Human UGT1A3 Enzyme Conjugates Norursodeoxycholic Acid into a C23-ester Glucuronide in the Liver*  

PubMed Central

Norursodeoxycholic acid (norUDCA) exhibits efficient anti-cholestatic properties in an animal model of sclerosing cholangitis. norUDCA is eliminated as a C23-ester glucuronide (norUDCA-23G) in humans. The present study aimed at identifying the human UDP-glucuronosyltransferase (UGT) enzyme(s) involved in hepatic norUDCA glucuronidation and at evaluating the consequences of single nucleotide polymorphisms in the coding region of UGT genes on norUDCA-23G formation. The effects of norUDCA on the formation of the cholestatic lithocholic acid-glucuronide derivative and of rifampicin on hepatic norUDCA glucuronidation were also explored. In vitro glucuronidation assays were performed with microsomes from human tissues (liver and intestine) and HEK293 cells expressing human UGT enzymes and variant allozymes. UGT1A3 was identified as the major hepatic UGT enzyme catalyzing the formation of norUDCA-23G. Correlation studies using samples from a human liver bank (n = 16) indicated that the level of UGT1A3 protein is a strong determinant of in vitro norUDCA glucuronidation. Analyses of the norUDCA-conjugating activity by 11 UGT1A3 variant allozymes identified three phenotypes with high, low, and intermediate capacity. norUDCA is also identified as a competitive inhibitor for the hepatic formation of the pro-cholestatic lithocholic acid-glucuronide derivative, whereas norUDCA glucuronidation is weakly stimulated by rifampicin. This study identifies human UGT1A3 as the major enzyme for the hepatic norUDCA glucuronidation and supports that some coding polymorphisms affecting the conjugating activity of UGT1A3 in vitro may alter the pharmacokinetic properties of norUDCA in cholestasis treatment.

Trottier, Jocelyn; El Husseini, Diala; Perreault, Martin; Paquet, Sophie; Caron, Patrick; Bourassa, Sylvie; Verreault, Melanie; Inaba, Ted T.; Poirier, Guy G.; Belanger, Alain; Guillemette, Chantal; Trauner, Michael; Barbier, Olivier

2010-01-01

133

Evaluation of the DNA damaging potential of cannabis cigarette smoke by the determination of acetaldehyde derived N2-ethyl-2'-deoxyguanosine adducts.  

PubMed

Acetaldehyde is an ubiquitous genotoxic compound that has been classified as a possible carcinogen to humans. It can react with DNA to form primarily a Schiff base N(2)-ethylidene-2'-deoxyguanosine (N(2)-ethylidene-dG) adduct. An online column-switching valve liquid chromatography tandem mass spectrometry (LC-MS/MS) selected reaction monitoring (SRM) method was developed for the determination of N(2)-ethylidene-dG adducts in DNA following reduction with sodium cyanoborohydride (NaBH(3)CN) to the chemically stable N(2)-ethyl-2'-deoxyguanosine (N(2)-ethyl-dG) adduct. Accurate quantitation of the adduct was obtained by the addition of the [(15)N(5)]N(2)-ethyl-dG stable isotope-labeled internal standard prior to enzymatic hydrolysis of the DNA samples to 2'-deoxynucleosides with the incorporation of NaBH(3)CN in the DNA hydrolysis buffer. The method required 50 microg of hydrolyzed DNA on column for the analysis, and the limit of detection for N(2)-ethyl-dG was 2.0 fmol. The analysis of calf thymus DNA treated in vitro with acetaldehyde (ranging from 0.5 to 100 mM) or with the smoke generated from 1, 5, and 10 cannabis cigarettes showed linear dose-dependent increases in the level of N(2)-ethyl-dG adducts (r = 0.954 and r = 0.999, respectively). Similar levels (332.8 +/- 21.9 vs 348.4 +/- 19.1 adducts per 10(8) 2'-deoxynucleosides) of N(2)-ethyl-dG adducts were detected following the exposure of calf thymus DNA to 10 tobacco or 10 cannabis cigarettes. No significant difference was found in the levels of N(2)-ethyl-dG adducts in human lung DNA obtained from nonsmokers (n = 4) and smokers (n = 4) with the average level observed as 13.3 +/- 0.7 adducts per 10(8) 2'-deoxynucleosides. No N(2)-ethyl-dG adducts were detected in any of the DNA samples following analysis with the omission of NaBH(3)CN from the DNA hydrolysis buffer. In conclusion, these results provide evidence for the DNA damaging potential of cannabis smoke, implying that the consumption of cannabis cigarettes may be detrimental to human health with the possibility to initiate cancer development. PMID:19449825

Singh, Rajinder; Sandhu, Jatinderpal; Kaur, Balvinder; Juren, Tina; Steward, William P; Segerbäck, Dan; Farmer, Peter B

2009-06-01

134

Headspace single-drop microextraction and GC-ECD determination of chlorpyrifos-ethyl in rat liver.  

PubMed

The present work describes a headspace single-drop microextraction (HS-SDME) method in conjunction with gas chromatography electron capture detection (GC-ECD) for the determination of an organophosphate insecticide, chlorpyrifos-ethyl (CPF), in rat liver. Sample preparation included tissue homogenization with methanol in the presence of anhydrous sodium sulfate in order to isolate CPF from the matrix, followed by dilution with 10 mL of 0.1 M H(2)SO(4) and headspace microextraction to a 2-microL drop of 1-octanol. The main factors affecting extraction efficiency were optimized [temperature 90 degrees C, preheating and extraction times of eight and six minutes, respectively, 2 g of (NH(4))(2)SO(4), stirring rate of 1000 rpm, 200 microL of methanolic extract]. The method allows for the separation and quantitation of residue levels of CPF in the livers of rats exposed orally to that insecticide. Using internal standardization (with chlorpyrifos-methyl used as an internal standard), the linearity of the method was demonstrated in the range 10-2500 ng g(-1) with a correlation coefficient R > 0.996 and a satisfactory level of precision (RSD 3.85%, n = 6). Moreover, the results obtained with the new method do not differ from those obtained with the conventional residue method used in our laboratory. The feasibility of this HS-SDME approach as an equivalent analytical method for the determination of CPF in rat liver that possesses advantages such as low cost, low solvent consumption and high throughput was confirmed. PMID:18299820

Wielgomas, Bartosz; Czarnowski, Wojciech

2008-02-26

135

Androstane3a,17b-Diol Glucuronide as a Steroid Correlate of Visceral Obesity in Men  

Microsoft Academic Search

Plasma levels of androstane-3a,17b-diol glucuronide (3a-DIOL-G) and androsterone glucuronide (ADT-G) as well as testosterone and adrenal C19 steroid concentrations were measured in a sample of 80 men in whom visceral adipose tissue (AT) accumulation was also determined by computed tomography. Plasma 3a-DIOL-G concen- trations showed significant positive correlations with total body fat mass (r 5 0.31; P , 0.05) and

FERNAND LABRIE; ALAIN BELANGER; CLAUDE BOUCHARD; ANGELO TREMBLAY; JEAN-PIERRE DESPRES

2009-01-01

136

Determination of benazolin-ethyl residues in soil and rape seed by SPE clean-up and GC with electron capture detection.  

PubMed

A method has been developed and established for residue determination of benazolin-ethyl in soil and rape seed samples by gas chromatography with electron capture detection (GC-ECD). Limits of quantification of the method are 0.005 mg/kg for both soil and rape seed, which are sufficiently below the maximum residue limit, and the limit of detection is 0.0023 ng. The average recoveries of the analyte range from 85.89 to 105.84% with relative standard deviations (coefficient of variation) less than 5.53% at the three spike levels (0.005, 0.1 and 0.5 mg/kg). The half-life of benazolin-ethyl in soil from the experimental field is 4.62 days. The final residues of benazolin-ethyl in soil and rape seed samples are lower than 0.005 mg/kg at harvest time. Direct confirmation of the analyte in real samples is achieved by GC-mass spectrometry. It is demonstrated that the proposed method is simple, rapid and efficient, and reliable to detect benazolin-ethyl residues in soil and rape seed samples. PMID:22718745

Liu, Xiaolu; Yang, Tao; Hu, Jiye

2012-06-19

137

Systematic Studies of Sulfation and Glucuronidation of 12 Flavonoids in the Mouse Liver S9 Fraction Reveals both Unique and Shared Positional Preferences  

PubMed Central

Sulfation and glucuronidation are the principal metabolic pathways of flavonoids, and extensive phase II metabolism is the main reason for their poor bioavailabilities. The purpose of this study was to compare the similarities and differences in the positional preference of glucuronidation versus sulfation in the mouse liver S9 fraction. The conjugating rates of seven mono-hydroxyflavones (HFs) (i.e., 2’-, 3’-, 4’-, 3-, 5-, 6-, and 7-HF), and five di-hydroxyflavones (diHFs), (i.e., 6,7-, 4’,7-, 3,7-, 5,7-, and 3,4’-diHF) were determined in three separate enzymatic reaction systems: (A) sulfation only, (B) glucuronidation only, or (C) simultaneous sulfation and glucuronidation (i.e., Sult-Ugt co-reaction). In general, glucuronidation rates were much faster than the sulfation rates. Among the HFs, 7-HF was the best substrate for both conjugation reactions, whereas 3-HF was rapidly glucuronidated but was not sulfated. As a result, the rank order of sulfation was very different from that of glucuronidation. Among the diHFs, regiospecific glucuronidation was limited to 7-OH and 3-OH positions, whereas regiospecific sulfation was limited to 7-OH and 4’-OH positions. Other positions (i.e., 6-OH and 5-OH) in diHFs were not conjugated. The positional preferences were essentially maintained in a Sult-Ugt co-reaction system, although sulfation was surprisingly enhanced. Lastly, sulfation and glucuronidation displayed different regiospecific- and substrate-dependent characteristics. In conclusion, glucuronidation and sulfation shared the same preference for 7-OH position (of flavonoids) but displayed unique preference in other positions in that glucuronidation preferred 3-OH position whereas sulfation preferred 4’-OH position.

Tang, Lan; Zhou, Juan; Yang, Cai-Hua; Xia, Bi-Jun; Hu, Ming; Liu, Zhong-Qiu

2012-01-01

138

Determination of methyltin compounds in urine of occupationally exposed and general population by in situ ethylation and headspace SPME coupled with GC-FPD  

Microsoft Academic Search

A method for the determination of methyltin compounds in human urine samples was developed using headspace solid-phase microextration (HS-SPME) coupled with gas chromatographic separation and flame photometric detection. Three methyltin compounds, monomethyltin (MMT), dimethyltin (DMT), and trimethyltin (TMT) were in situ ethylated by sodium tetraethylborate (NaBEt4) for SPME and GC-FPD analysis. Under the optimized condition, the detection limits of MMT,

Zongyan Cui; Kegang Zhang; Qunfang Zhou; Jiyan Liu; Guibin Jiang

2011-01-01

139

Ethyl propiolate as a post-column derivatization reagent for thiols: Development of a green liquid chromatographic method for the determination of glutathione in vegetables  

Microsoft Academic Search

The present study reports the development, validation and application of a new green liquid chromatographic method for the determination of glutathione (GSH) in vegetable samples. In this work we introduce—for the first time—ethyl propiolate (EP) as an advantageous post-column derivatization reagent for thiolic compounds. GSH (tR=6.60min) and N-acetylcysteine (NAC, internal standard) (tR=11.80min) were separated efficiently from matrix endogenous compounds by

Constantinos K. Zacharis; Paraskevas D. Tzanavaras; Anastasia Zotou

2011-01-01

140

Simultaneous determination of myristyl nicotinate, nicotinic acid, and nicotinamide in rabbit plasma by liquid chromatography–tandem mass spectrometry using methyl ethyl ketone as a deproteinization solvent  

Microsoft Academic Search

Myristyl nicotinate (Nia-114) is an ester prodrug being developed for delivery of nicotinic acid (NIC) into the skin for prevention of actinic keratosis and its progression to skin cancer. To facilitate dermal studies of Nia-114, a novel liquid chromatography–tandem mass spectrometry (LC–MS\\/MS) method using methyl ethyl ketone (MEK) as a deproteinization solvent was developed and validated for the simultaneous determination

Paul Catz; Walter Shinn; Izet M. Kapetanovic; Hyuntae Kim; Moonsun Kim; Elaine L. Jacobson; Myron K. Jacobson; Carol E. Green

2005-01-01

141

Gas-Chromatographic Determination of Sarin, Soman, and O Isobutyl S -2-( N , N -Diethylamino)ethyl Methylphosphonothioate (a VX-Like Compound) Traces in Water  

Microsoft Academic Search

A gas-chromatographic procedure for the determination of O-isobutyl S-2-(N,N-diethylamino)ethyl methylphosphonothioate (VX), sarin, and soman in water at levels of 2 × 10–6, 5 × 10–5, and 2 × 10–6 mg\\/L, respectively, was proposed. The procedure includes liquid–liquid extraction with the use of salting-out agents, back extraction, and evaporation. In this case, the VX compound was converted into O-isobutyl O-methyl methylphosphonate

I. N. Stan'kov; A. A. Sergeeva; I. D. Derevyagina; K. V. Konovalov

2003-01-01

142

Gas-chromatographic determination of O -isobutyl- S -2-( N,N -diethylamino)ethyl methylphosphonothioate (VX-like compound) and O -isopropyl methylphosphonofluoridate (Sarin) traces in slag  

Microsoft Academic Search

Procedures for the determination of 04sobutyl- S-2-(N,N-diethylamino)ethyl methylphosphonothioate (VX-like compound) and sarin traces in slag at levels of 5 × 10-5 and 1 × 10-2 mg\\/kg, respectively, were developed. The procedures are based on the extraction of organophosphorus chemical warfare agents\\u000a from slag, the preconcentration of the extract, and the conversion of the analytes into dialkyl methylphos-phonates with the\\u000a use

I. N. Stans’kov; V. B. Kondrats’ev; E. N. Glukhan; V. I. Tsekhmister; S. V. Sadovnikov; A. P. Suchkov; I. D. Derevyagina

2010-01-01

143

Effect of galactosamine-induced hepatic UDP-glucuronic acid depletion on acetaminophen elimination in rats. Dispositional differences between hepatically and extrahepatically formed glucuronides of acetaminophen and other chemicals.  

PubMed

Galactosamine (GAL) markedly depletes hepatic UDP-glucuronic acid (UDP-GA) whereas extrahepatic UDP-GA is minimally affected. This suggests that GAL predominantly inhibits hepatic glucuronidation. Therefore, the effect of GAL-induced hepatic UDP-GA depletion was examined in bile duct-cannulated rats to determine the role of hepatic glucuronidation in the disposition of acetaminophen (AA). GAL markedly altered the fate of AA-glucuronide but had little or no effect upon other AA metabolites. GAL decreased the biliary excretion of AA-glucuronide up to 92%, whereas reductions in blood levels and urinary excretion of AA-glucuronide did not exceed 50%. This suggests that AA-glucuronide excreted in bile is predominantly of hepatic origin whereas AA-glucuronide found in blood and urine is derived from both hepatic and extrahepatic tissues. Data in the present and previous studies [Gregus, Watkins, Thompson, Klaassen: J. Pharmacol. Exp. Ther. 225, 256, (1983)] indicate that GAL greatly reduced the biliary excretion of AA- and valproic acid-glucuronide whereas the biliary excretion of the glucuronides of phenolphthalein, iopanoic acid, bilirubin, and diethylstilbestrol was only partially decreased. This difference appears to be largely due to differential contributions by the liver and extrahepatic tissues in the glucuronidation of various compounds as well as the availability of glucuronides formed in extrahepatic tissues for biliary excretion. Specifically, the extrahepatically formed glucuronide conjugates of AA and valproic acid are not readily available for biliary excretion whereas the glucuronides of the other compounds are readily excreted into bile.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2903018

Gregus, Z; Madhu, C; Goon, D; Klaassen, C D

144

Species and Gender Differences Affect the Metabolism of Emodin via Glucuronidation  

PubMed Central

The aim of the present study was to define the mechanisms responsible for poor bioavailability of emodin by determining its metabolism using in vitro and in situ disposition models of the intestine and liver. Liver microsomes of mice, rats, guinea pigs, dogs, and humans were used along with the rat intestinal perfusion model and the rat intestinal microsomes. In the rat intestine, excretion rates of emodin-3-O-glucuronide were significantly different (p?glucuronidation in liver microsomes was species-dependent, and Km values varied 5.7-fold (3.2–18.2 ?M) in males and 2.8-fold (4.6–13.0 ?M) in females. The male intrinsic clearance (CLint) values differed by 5-fold (27.6–138.3 mL h?1?mg?1 protein), and female CLint values differed by 4.3-fold (24.3–103.5 mL h?1?mg?1 protein). Since CLint values of emodin glucuronidation were 10-fold higher than that of isoflavones, emodin was considered rapidly glucuronidated. In contrast to the large species-dependent effects on Km and CLint values, gender had a smaller effect on these kinetic parameters (2-fold, p?glucuronidation rates obtained using liver microsomes from various experimental animals of the same gender correlated well with those in human liver microsomes. In conclusion, Rapid metabolism by UDP-glucuronosyltransferase is the major reason why emodin has poor bioavailability. Species and gender affected emodin metabolism to a different degree, and experimental animals are expected to be useful in predicting emodin glucuronidation in humans.

Liu, Wei; Tang, Lan; Ye, Ling; Cai, Zheng; Xia, Bijun; Zhang, Jiajie

2010-01-01

145

Quantitative analysis of propofol-glucuronide in hair as a marker for propofol abuse.  

PubMed

The inappropriate or illegal use of propofol has recently come to the fore as a serious social issue in South Korea. Thus, in spite of its superior potency as a therapeutic drug, propofol was classified as a controlled drug under the purview of Narcotics Control Law in South Korea in February of 2011. Accordingly, the determination of propofol and/or its metabolites in biological specimens is required to prove ingestion. Therefore, to demonstrate chronic ingestion, a quantitative analytical method for propofol-glucuronide in hair was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). This method was applied to measure propofol-glucuronide in hair samples from 23 propofol abuse suspects and in both pigmented and nonpigmented hair from rats which had ingested propofol. Propofol-glucuronide in hair was extracted in methanol and then filtered and analyzed by LC-MS/MS with electrospray ionization in negative mode. The validation results of selectivity, matrix effect, recovery, linearity, precision and accuracy, and processed sample stability were satisfactory. The limit of detection was 20 pg/10 mg hair and the limit of quantification was 50 pg/10 mg hair. The concentration range of propofol-glucuronide in hair segments from 23 propofol abuse suspects was shown up to 1,410 pg/mg. The animal study demonstrated that the presence of melanin did not affect the deposition of propofol-glucuronide in hair. Thus, we propose propofol-glucuronide in hair as a marker for propofol abuse. This method will be very useful for monitoring the inappropriate use of propofol for both legal and public health aspects. PMID:23771527

Kim, Jihyun; In, Sanghwan; Park, Yuran; Park, Meejung; Kim, Eunmi; Lee, Sooyeun

2013-06-16

146

Characterization of raloxifene glucuronidation: potential role of UGT1A8 genotype on raloxifene metabolism in vivo.  

PubMed

Raloxifene is a second-generation selective estrogen receptor modulator used for the prevention and treatment of osteoporosis and the prevention of breast cancer in postmenopausal women. Raloxifene is extensively metabolized by glucuronidation to form raloxifene-6-glucuronide (ral-6-Gluc) and raloxifene-4'-glucuronide (ral-4'-Gluc). The goal of the present study was to determine whether functional polymorphisms in active UGTs could play a role in altered raloxifene glucuronidation in vivo. Using homogenates from HEK293 UGT-overexpressing cell lines, raloxifene was shown to be glucuronidated primarily by the hepatic UGTs 1A1 and 1A9 and the extra-hepatic UGTs 1A8 and 1A10; no detectable raloxifene glucuronidation activity was found for UGT2B enzymes. Functional UGT1A1 transcriptional promoter genotypes were significantly (Ptrend = 0.005) associated with ral-6-Gluc formation in human liver microsomes, and, consistent with the decreased raloxifene glucuronidation activities observed in vitro with cell lines overexpressing UGT1A8 variants, the UGT1A8*2 variant was significantly (P = 0.023) correlated with total raloxifene glucuronide formation in human jejunum homogenates. While ral-4'-Gluc exhibited 1:100th the anti-estrogenic activity of raloxifene itself as measured by binding to the estrogen receptor, raloxifene glucuronides comprised about 99% of the circulating raloxifene dose in raloxifene-treated subjects, with ral-4'-Gluc comprising ~70% of raloxifene glucuronides. Plasma ral-6-Gluc (Ptrend = 0.0025), ral-4'-Gluc (Ptrend = 0.001), and total raloxifene glucuronides (Ptrend = 0.001) were increased in raloxifene-treated subjects who were predicted slow metabolizers [UGT1A8 (*1/*3)] versus intermediate metabolizers [UGT1A8 (*1/*1) or UGT1A8 (*1/*2)] versus fast metabolizers [UGT1A8 (*2/*2). These data suggest that raloxifene metabolism may be dependent on UGT1A8 genotype and that UGT1A8 genotype may play an important role in overall response to raloxifene. PMID:23682072

Sun, Dongxiao; Jones, Nathan R; Manni, Andrea; Lazarus, Philip

2013-05-16

147

Experimental and theoretical determination of transition dipole moments of ethyl 5-(4-aminophenyl)- and 5-(4-dimethylaminophenyl)-3-amino-2,4-dicyanobenzoate  

NASA Astrophysics Data System (ADS)

The absorption and fluorescence transition dipole moments (widehat{M}ge and widehat{M}eg) for ethyl 5-(4-aminophenyl)-3-amino-2, 4-dicyanobenzoate (EAADCy) and ethyl 5-(4-dimethylaminophenyl)-3-amino-2, 4-dicyanobenzoate (EDMAADCy) have been determined on the basis of the steady-state and time-resolved spectroscopic measurements and semiempirical quantum-chemical calculations. The values of the transition dipole moments of perpendicular and flattened forms of the investigated molecules were estimated as a function of the solvent polarity. Noted differences between the absorption and emission transition dipole moments (i.e., widehat{M}ge/widehat{M}ge ? 1) confirm that the change of the electronic and molecular structure take place in the excited state.

Jozefowicz, M.; Heldt, J. R.; Heldt, J.

2013-10-01

148

Stereoselective urinary excretion of formoterol and its glucuronide conjugate in human  

PubMed Central

Aims Formoterol is an inhaled ?2-adrenoceptor agonist used as a racemic mixture of the active (R; R)- and inactive (S; S)-enantiomers (rac-formoterol). Glucuronidation is an important route of metabolism in humans which occurs faster for (S; S)-formoterol in human liver microsomes. The aim of this study was to investigate the stereoselectivity of urinary excretion of formoterol and its glucuronide conjugate after oral dosing with rac-formoterol. Methods Seven nonsmoking volunteers (six males, one female) were included in the study. After an overnight fast, a single 60 µg oral dose of rac-formoterol fumarate dihydrate was ingested. Urine samples were collected at 1 h intervals for the first 4 h, and at 6, 8, 12 and 24 h after dosing. Formoterol enantiomers were analysed by chiral h.p.l.c. assay and formoterol glucuronides were determined as formoterol enantiomers after enzymatic cleavage with ?-glucuronidase. Results The female subject displayed a different pattern of metabolism and statistical analysis was therefore limited to data for the six males. The median (range) of the total urinary excretion of formoterol was 37.8% (20.9–51.2%) of the dose. The medians (ranges) of the amounts of (R; R)- and (S; S)-formoterol and of (R; R)- and (S; S)-formoterol glucuronide excreted were 2.1 (1.0–2.9), 3.5 (2.6–3.8), 21.0 (13.1–31.0) and 10.3 (4.2–14.6)%, respectively, of the dose. Unchanged (S; S)-formoterol excretion was significantly greater than that of unchanged (R; R)-formoterol and (R; R)-formoterol glucuronide excretion was significantly greater than that of (S; S)-formoterol glucuronide. The total RR-formoterol (unchanged drug plus glucuronide) excreted was significantly greater than the total (S; S)-formoterol. Conclusions Our study demonstrates that the urinary excretion of formoterol in male humans after oral administration of rac-formoterol is stereoselective with preferential excretion of the active (R; R)-formoterol as unchanged drug and glucuronide. The different pattern of metabolism in the female subject provides impetus for further studies of the effect of gender on the stereoselective metabolism and pharmacokinetics of formoterol.

Zhang, Mei; Fawcett, J Paul; Shaw, John P

2002-01-01

149

In Vitro Glucuronidation of 2,2-Bis(bromomethyl)-1,3-propanediol by Microsomes and Hepatocytes from Rats and Humans  

PubMed Central

2,2-Bis(bromomethyl)-1,3-propanediol (BMP) is a brominated flame retardant used in unsaturated polyester resins. In a 2-year bioassay BMP was shown to be a multisite carcinogen in rats and mice. Because glucuronidation is the key metabolic transformation of BMP by rats, in this study the in vitro hepatic glucuronidation of BMP was compared across several species. In addition, the glucuronidation activities of human intestinal microsomes and specific human hepatic UDP-glucuronosyltransferase (UGT) enzymes for BMP were determined. To explore other possible routes of metabolism for BMP, studies were conducted with rat and human hepatocytes. Incubation of hepatic microsomes with BMP in the presence of UDP-glucuronic acid resulted in the formation of a BMP monoglucuronide. The order of hepatic microsomal glucuronidation activity of BMP was rats, mice ? hamsters > monkeys ? humans. The rate of glucuronidation by rat hepatic microsomes was 90-fold greater than that of human hepatic microsomes. Human intestinal microsomes converted BMP to BMP glucuronide at a rate even lower than that of human hepatic microsomes. Among the human UGT enzymes tested, only UGT2B7 had detectable glucuronidation activity for BMP. BMP monoglucuronide was the only metabolite formed when BMP was incubated with suspensions of freshly isolated hepatocytes from male F-344 rats or with cryopreserved human hepatocytes. Glucuronidation of BMP in human hepatocytes was extremely low. Overall, the results support in vivo studies in rats in which BMP glucuronide was the only metabolite found. The poor glucuronidation capacity of humans for BMP suggests that the pharmacokinetic profile of BMP in humans will be dramatically different from that of rodents.

Rad, Golriz; Hoehle, Simone I.; Kuester, Robert K.

2010-01-01

150

SIMULTANEOUS DETERMINATION OF P-HYDROXYBENZOIC ACID, 2PHENOXYETHANOL, METHYLPHYDROXYBENZOATE, ETHYL-P-HYDROXYBENZOATE, PROPYLPHYDROXYBENZOATE, ISOBUTYLPHYDROXYBENZOATE, AND N-BUTYL-P-HYDROXYBENZOATE IN SENSELLE LUBRICANT FORMULATION BY HPLC  

Microsoft Academic Search

A new and simple reversed-phase high-performance liquid chromatographic (HPLC) method has been developed and validated for the simultaneous determination of p-hydroxybenzoic acid, 2-phenoxyethanol, methyl-p-hydroxybenzoate, ethyl-p-hydroxybenzoate, propyl-p-hydroxybenzoate, iso-butyl-p-hydroxybenzoate and n-butyl-p-hydroxybenzoate preservatives in senselle lubricant formulation. The seven compounds were separated on a C18 ChromSpher polymeric octadecylsilane (ODS)-encapsulated spherical silica column with acetonitrile-tetrahydrofuran-water, 22:14:64 (v\\/v\\/v) as mobile phase at flow rate of

Ghulam A. Shabir

2011-01-01

151

Determination of peptides and amino acids from wool and beer with sensitive fluorescent reagent 2-(9-carbazole)-ethyl chloroformate by reverse phase high-performance liquid chromotography and liquid chromotography mass spectrometry  

Microsoft Academic Search

A new method for the sensitive determination of amino acids and peptides using the tagging reagent 2-(9-carbazole)-ethyl chloroformate (CEOC) with fluorescence (FL) detection has been developed. Identification of derivatives was carried out by liquid chromotography mass spectrometry. The chromophore in the 2-(9-fluorenyl)-ethyl chloroformate (FMOC) reagent was replaced by carbazole, which resulted in a sensitive fluorescence lerivatizing agent CEOC. CEOC can

Jinmao You; Yichu Shan; Liang Zhen; Lin Zhang; Yukui Zhang

2003-01-01

152

The small intestine can both absorb and glucuronidate luminal flavonoids  

Microsoft Academic Search

We have studied the perfusion of the jejunum and ileum in an isolated rat intestine model with flavonoids and hydroxycinnamates and the influence of glycosylation on the subsequent metabolism. Flavone and flavonol glucosides and their corresponding aglycones are glucuronidated during transfer across the rat jejunum and ileum and this glucuronidation occurs without the need for gut microflora. Furthermore, this suggests

Jeremy P. E Spencer; George Chowrimootoo; Ruksana Choudhury; Edward S Debnam; S. Kaila Srai; Catherine Rice-Evans

1999-01-01

153

The pharmacokinetics of morphine and morphine glucuronides in kidney failure.  

PubMed

The pharmacokinetics of morphine and its glucuronide metabolites were investigated in three groups of patients with kidney failure (nondialyzed, receiving dialysis, and transplantation) and compared with a group of normal healthy volunteers. Patients in all three renal groups were undergoing surgical procedures (nondialyzed group undergoing arteriovenous fistula formation, dialysis group undergoing placement of a peritoneal dialysis catheter, and the transplant group undergoing live donor kidney transplant). A sensitive, specific high-performance liquid chromatographic assay was used to quantitate morphine, morphine-3-glucuronide, and morphine-6-glucuronide. Patients with kidney failure had a significantly increased morphine area under the curve (AUC) compared with control subjects. There was also an increase in the metabolites morphine-3-glucuronide and morphine-6-glucuronide that was severalfold greater than the increase in morphine AUC. This metabolite accumulation was reversed by kidney transplantation, providing an elegant confirmation on the role of the kidney in morphine pharmacology. PMID:8354025

Osborne, R; Joel, S; Grebenik, K; Trew, D; Slevin, M

1993-08-01

154

Identification of the rabbit liver UDP-glucuronosyltransferase catalyzing the glucuronidation of 4-ethoxyphenylurea (dulcin).  

PubMed

Dulcin (DL), 4-ethoxyphenylurea, a synthetic chemical about 200 times as sweet as sucrose, has been proposed for use as an artificial sweetener. DL is excreted as a urinary ureido-N-glucuronide after oral administration to rabbits. The phenylurea N-glucuronide is the only ureido conjugate with glucuronic acid known at present; therefore, DL is interesting as a probe to search for new functions of UDP-glucuronosyltransferases (UGTs). Seven UGT isoforms (UGT1A3, UGT1A4, UGT1A6, UGT1A7, UGT2B13, UGT2B14, and UGT2B16) have been identified from rabbit liver, but these UGTs have not been investigated using DL as a substrate. In this work, the identities of UGT isoforms catalyzing the formation of DL glucuronide were investigated using rabbit liver microsomes (RabLM) and cloned/expressed as rabbit UGT isoforms. DL-N-glucuronide (DNG) production was determined quantitatively in RabLM and homogenates of COS-7 cells expressing each UGT isoform by using electrospray liquid chromatography-tandem mass spectrometry. Analysis of DNG formation using RabLM, by Eadie-Hofstee plot, gave a Vmax of 0.911 nmol/min/mg protein and the Km of 1.66 mM. DNG formation was catalyzed only by cloned expressed rabbit UGT1A7 and UGT2B16 (Vmax of 3.98 and 1.16 pmol/min/mg protein and a Km of 1.23 and 1.69 mM, respectively). Substrate inhibition of UGT1A7 by octylgallate confirmed the significant contribution of UGT1A7 to the formation of DNG. Octylgallate was further shown to competitively inhibit DNG production by RabLM (Ki = 0.149 mM). These results demonstrate that UGT1A7 is the major isoform catalyzing the N-glucuronidation of DL in RabLM. PMID:15448114

Uesawa, Yoshihiro; Staines, Adam G; O'Sullivan, Audrey; Mohri, Kiminori; Burchell, Brian

2004-09-24

155

21 CFR 177.1320 - Ethylene-ethyl acrylate copolymers.  

Code of Federal Regulations, 2013 CFR

...1520. (1) Specifications â(i) Infrared identification. Ethylene-ethyl acrylate...be identified by their characteristic infrared spectra. (ii) Quantitative determination...ethyl acrylate can be determined by the infrared spectra. Prepare a scan from...

2013-04-01

156

Optimization of an analytical method for determining organotin compounds in fish tissue by base-hydrolysis pretreatment and simultaneous ethylation-extraction procedures.  

PubMed

To determine butyl- and phenyl-tins in fish muscle, a method including base digestion pretreatment, followed by a simultaneous ethylation-extraction procedure and gas chromatograph-flame photometric detector (GC-FPD) analysis is outlined. Key parameters that influence analyte recovery were investigated and optimized. A solution of 3% (w/v) potassium hydroxide (KOH) and 1 h digestion time at 60 degrees C were chosen in the base digestion step, to ensure complete solubilization of fish muscle and the decomposition of organotins was found to be insignificant. We found that the ratio of fish muscle/reaction solution should not exceed 0.2 g (dry weight) per 100 mL in order to avoid the matrix effect caused by the binding of hydrolyzed fish tissue with organotin ions. Ethylation of organotins were conducted at pH 6-7 with a 1% (w/v) sodium tetraethylborate (NaBEt(4)) solution for 1 h. This simple and timesaving procedure should be able to be applied to the routine analysis of organotins in other bio-tissues. PMID:17386465

Tang, Chuan-Ho; Wang, Wei-Hsien

2006-08-22

157

Simultaneous determination of organotin compounds in textiles by gas chromatography-flame photometry following liquid/liquid partitioning with tert-butyl ethyl ether after reflux-extraction.  

PubMed

A rapid and relatively clean method for determining six organotin compounds (OtC) in textile goods with a gas chromatograph equipped with a conventional flame photometric detector (GC-FPD) has been developed. After the reflux-extraction to use methanol containing 1% (v/v) of hydrochloric acid, five hydrophobic OtC (e.g. tributyltin: TBT) and slightly less hydrophobic dibutyltin (DBT) could be drawn out through partitioning between the methanolic buffer solution and tert-butyl ethyl ether instead of hazardous dichloromethane, of which usage is provided by the official-methods notified in Japan, and following the ethylation procedure to use sodium tetraethylborate, the OtC were determined with the GC-FPD. The recoveries of DBT, TBT, tetrabutyltin, triphenyltin, dioctyltin, and trioctyltin from textile products (cloth diaper, socks, and undershirt) were 60-77, 89-98, 86-94, 71-78, 85-109, and 70-79% respectively, and their coefficients of variation were 2.5-16.5%. Calibration curves for OtC were linear (0.01-0.20?gasSnmL(-1)), and the correlation coefficients were 0.9922-1.0000. Their detection limits were estimated to be 2.7-9.7ngasSng(-1). These data suggested that this method would be applicable to their simultaneous determination. Five retailed textile goods were analyzed by this proposed method, and 0.013-0.65µgasSng(-1) of OtC (e.g. DBT) were determined in three. Moreover, a possibility that various OtC including non-targeted species in textile would be specifically detected by applying the studying speciation-technique of controlling signal intensity-flame fuel gas pressures of the GC-FPD was found. PMID:24054605

Hamasaki, Tetsuo

2013-05-02

158

Determination of glucose and cellobiose dissolved in the ionic liquid 1-ethyl-3-methylimidazolium acetate using Fourier transform infrared spectroscopy.  

PubMed

The conversion of biogenic carbohydrate feedstock to chemicals or energy equivalents is a promising approach to solve the problem of limited fossil fuel reserves. Some concepts to accomplish these transformations are based on ionic liquids (ILs) due to their ability to dissolve biopolymers, such as cellulose, and even complex biopolymer mixtures, such as wood. However, concerning control of such conversions, a reliable tool for process analytics is required. In this paper we demonstrate the applicability of Fourier transform infrared (FT-IR) spectroscopy to perform quantitative concentration measurements of glucose and cellobiose as two examples of carbohydrates dissolved in the room-temperature ionic liquid [EMIM][OAc] (1-ethyl-3-methylimidazolium acetate). For this purpose, binary mixtures in the range 0-20 wt% have been studied. A previously developed method for the data analysis, which was based on the Beer-Lambert relation, has been universalized by employing empirical correlations between the measured quantity (i.e., extinction) and the carbohydrate concentration. In the entire spectral range under investigation (500-4000 cm(-1)) numerous individual wave-numbers have been identified, allowing quantitative measurements with high accuracy and precision. PMID:19796487

Kiefer, Johannes; Obert, Katharina; Fries, Jürgen; Bösmann, Andreas; Wasserscheid, Peter; Leipertz, Alfred

2009-09-01

159

Wheel running attenuates the antinociceptive properties of morphine and its metabolite, morphine-6-glucuronide, in rats  

Microsoft Academic Search

Recent work has shown that chronic exercise is associated with a reduction in the pain-relieving actions of opioid drugs in experimental animals. To determine whether this reduction represents an interaction between exogenously administered opioids and the endogenous opioid system, or is the result of altered drug pharmacokenitics, the antinociceptive actions of morphine and its metabolite, morphine-6-glucuronide (M6G), were compared in

Wendy Foulds Mathes; Robin B Kanarek

2001-01-01

160

Urinary pharmacokinetics of the glucuronide and sulfate conjugates of genistein and daidzein.  

PubMed

Consumption of soybean-rich diets is thought to provide significant health benefits such as prevention of cancer, primarily because of the high contents of factors such as the isoflavones genistein and daidzein. Isoflavones circulate and are excreted into the urine mainly as glucuronide and sulfate conjugates. This study was conducted to determine the urinary pharmacokinetics of sulfate and glucuronide conjugates of genistein and daidzein. Twelve volunteers consumed a soy beverage providing 1 and 0.6 mg/kg body weight of genistein and daidzein equivalents, respectively. Urine was collected at various times during the 48 h after soy consumption and was digested with either glucuronidase or sulfatase, and the liberated aglycones were extracted and analyzed by liquid chromatography-mass spectrometry. Urinary isoflavone sulfate levels were determined by two methods: (a) assessment of aglycone after sulfatase hydrolysis (measured); or (b) calculated by subtracting the aglycone + glucuronide levels from the total urinary isoflavone levels. The apparent terminal half-life for daidzein sulfate (3.9+/-0.5 h) that was determined from sulfatase-treated urine was 32% shorter (P < or = 0.02) than that of the calculated daidzein sulfate (5.7+/-0.08 h). A similar trend was obtained for genistein sulfate (4.5+/-0.7 versus 6.8+/-0.1 h). The apparent terminal half-lives for genistein and daidzein glucuronides were 6.0+/-0.4 and 3.8+/-0.4 h, respectively. These data suggest that the measured urinary isoflavone sulfate values provide a better understanding of the pharmacokinetics than the calculated values. Additional studies are needed to determine whether the apparent terminal half-lives can be attributed to elimination or absorption processes. PMID:10794486

Shelnutt, S R; Cimino, C O; Wiggins, P A; Badger, T M

2000-04-01

161

Direct quantification of steroid glucuronides in human urine by liquid chromatography–electrospray tandem mass spectrometry  

Microsoft Academic Search

A method based on liquid chromatography–tandem mass spectrometry (LC–MS\\/MS) for the direct quantification of glucuronides of testosterone (TG), epitestosterone (EPG), androsterone (AG) and etiocholanolone (ETG) has been developed. The method allowed for the direct determination of these analytes avoiding hydrolysis and derivatization, which are usual steps in commonly used methods based on gas chromatography–mass spectrometry (GC–MS). The electrospray ionization and

Oscar J. Pozo; Peter Van Eenoo; Wim Van Thuyne; Koen Deventer; Frans T. Delbeke

2008-01-01

162

Pharmacokinetics of acetaminophen, codeine, and the codeine metabolites morphine and codeine-6-glucuronide in healthy Greyhound dogs  

PubMed Central

The purpose of this study was to determine the pharmacokinetics of codeine and the active metabolites morphine and codeine-6-glucuronide after IV codeine administration and the pharmacokinetics of acetaminophen (APAP), codeine, morphine, and codeine-6-glucuronide after oral administration of combination product containing acetaminophen and codeine to dogs. Six healthy Greyhound dogs were administered 0.734 mg/kg codeine IV and acetaminophen (10.46 mg/kg mean dose) with codeine (1.43 mg/kg mean dose) orally. Blood samples were obtained at predetermined time points for the determination of codeine, morphine, and codeine-6-glucuronide plasma concentrations by LC/MS and acetaminophen by HPLC with UV detection. Codeine was rapidly eliminated after IV administration (T½ =1.22 hr; clearance=29.94 mL/min/kg; volume of distribution=3.17 L/kg) with negligible amounts of morphine present, but large amounts of codeine-6-glucuronide (CMAX=735.75 ng/mL) were detected. The oral bioavailability of codeine was 4%, morphine concentrations were negligible, but large amounts of codeine-6-glucuronide (CMAX=1952.86 ng/mL) were detected suggesting substantial first pass metabolism. Acetaminophen was rapidly absorbed (CMAX=6.74 ?g/mL; TMAX=0.85 hr) and eliminated (T½=0.96 hr). In conclusion, the pharmacokinetics of codeine were similar to other opioids in dogs with a short half-life, rapid clearance, large volume of distribution, and poor oral bioavailability. High concentrations of codeine-6-glucuronide were detected after IV and oral administration.

KuKanich, Butch

2009-01-01

163

Identification of sulfur interferences during organotin determination in harbour sediment samples by sodium tetraethyl borate ethylation and gas chromatography-pulsed flame photometric detection.  

PubMed

Because of the high toxicity of organotin compounds and the current regulation about their applications, analytical method usable in routine analysis is required. A speciation procedure based on NaBEt4 ethylation and GC-PFPD analysis has shown to be suitable for the organotin determination. Unfortunately, some matrix effects were observed during the analysis of harbour sediments from Chile. These effects were identified as the alkylation of elemental sulfur and the coelution between the organotin compounds and some dialkylsulfides. The re-optimization of GC parameters and application of solid phase microextraction (SPME) were proposed to solve these analytical problems. Certified reference materials and different harbour sediment samples were analysed in order to evaluate the suitability of the methods for organotin control in complex environment samples. PMID:15387191

Bravo, Manuel; Lespes, Gäetane; De Gregori, Ida; Pinochet, Hugo; Potin-Gautier, Martine

2004-08-13

164

Experimental Determination of Densities and Isobaric Vapor-Liquid Equilibria of Methyl Acetate and Ethyl Acetate with Alcohols (C3 and C4) at 0.3 MPa  

NASA Astrophysics Data System (ADS)

The densities and excess volumes were determined at 298.15 K for the methyl acetate + 1-propanol, methyl acetate + 1-butanol, and ethyl acetate + 1-butanol mixtures. The vapor-liquid equilibria data at 0.3 MPa for these binary systems were obtained using a stainless steel equilibrium still. The activity coefficients were obtained from the experimental data using the Hayden and O'Connell method and the Yen and Woods equation. The binary systems in this study showed positive deviations from ideality. The experimental VLE data were verified with the point-to-point test of van Ness using the Barker routine and the Fredenslund criterion. The different versions of the UNIFAC and the ASOG group contribution models were applied.

Susial, Pedro; Estupiñan, Esteban J.; Castillo, Victor D.; Rodríguez-Henríquez, José J.; Apolinario, José C.

2013-10-01

165

Investigation of Immobilized Enzymes for Hydrolysis of Glucuronides in Urine.  

National Technical Information Service (NTIS)

Metabolism of certain drugs leads to the formation of conjugation products with glucuronic acid prior to excretion in urine. Thus, heroin is converted to morphine, which after conjugation with glucuronic acid, appears in the urine as morphine glucuronide....

D. J. Fink M. K. Bean R. D. Falb

1975-01-01

166

Testosterone sulphation and glucuronidation in the human liver: interindividual variability  

Microsoft Academic Search

Summary  Presystemic sulphation and glucuronidation at OH-C17 limits the bioavailability of testosterone; the aim of this investigation was to describe the variability in testosterone\\u000a sulphation and glucuronidation rates in the human liver. Liver samples were obtained from 61 women and 40 men of similar age\\u000a (mean 53 and 55 yers, respectively) submitted to surgery. The mean rate of testosterone sulphation was

Gian Maria Pacifici; A. Gucci; L. Giuliani

1997-01-01

167

Hepatic UDP-glucuronosyltransferase is responsible for eslicarbazepine glucuronidation.  

PubMed

Eslicarbazepine acetate (ESL) is a once-daily novel antiepileptic drug approved in Europe for use as adjunctive therapy for refractory partial-onset seizures with or without secondary generalization. Metabolism of ESL consists primarily of hydrolysis to eslicarbazepine, which is then subject to glucuronidation followed by renal excretion. In this study, we have identified that human liver microsomes (HLM) enriched with uridine 5'-diphosphoglucuronic acid give origin to a single Escherichia coli ?-glucuronidase-sensitive eslicarbazepine glucuronide (most likely the O-glucuronide). The kinetics of eslicarbazepine glucuronidation in HLM was investigated in the presence and absence of bovine serum albumin (BSA). The apparent K(m) were 412.2 ± 63.8 and 349.7 ± 74.3 ?M in the presence and absence of BSA, respectively. Incubations with recombinant human UDP glucuronosyltransferases (UGTs) indicated that UGT1A4, UGT1A9, UGT2B4, UGT2B7, and UGT2B17 appear to be involved in eslicarbazepine conjugation. The UGT with the highest affinity for conjugation was UGT2B4 (K(m) = 157.0 ± 31.2 and 28.7 ± 10.1 ?M, in the absence and presence of BSA, respectively). There was a significant correlation between eslicarbazepine glucuronidation and trifluoperazine glucuronidation, a typical UGT1A4 substrate; however, no correlation was found with typical substrates for UGT1A1 and UGT1A9. Diclofenac inhibited eslicarbazepine glucuronidation in HLM with an IC(50) value of 17 ?M. In conclusion, glucuronidation of eslicarbazepine results from the contribution of UGT1A4, UGT1A9, UGT2B4, UGT2B7, and UGT2B17, but the high-affinity component of the UGT2B4 isozyme may play a major role at therapeutic plasma concentrations of unbound eslicarbazepine. PMID:21673130

Loureiro, Ana I; Fernandes-Lopes, Carlos; Bonifácio, Maria J; Wright, Lyndon C; Soares-da-Silva, Patricio

2011-06-14

168

Spectrophotometric determination of boron in iron and steel with curcumin after separation by 2-ethyl-1,3-hexanediol-chloroform extraction.  

PubMed

A simple and reliable method for determining approximately 0.0001% or more of total boron in iron and low- and high-alloy steels is described. After the sample is decomposed at <70 degrees in the presence of hydrogen peroxide and potassium hydrogen fluoride, the insoluble material is filtered off and ultimately fused with sodium carbonate. The cooled melt is dissolved in dilute hydrochloric acid and the solution is combined with the main solution. Fluoride is subsequently complexed with zirconium and boron is separated from iron and other elements by extraction as borate from 1M sulphuric acid medium into chloroform containing 2-ethyl-1,3-hexanediol. Boron, in a 1-ml portion of the extract, is ultimately determined spectrophotometrically at 550 nm in an ethanol medium, after formation of the curcumin rosocyanin complex in a glacial acetic acid-concentrated sulphuric acid medium. Acid-soluble and acid-insoluble boron can also be determined. Common ions, including large amounts of manganese, chromium, vanadium, titanium, molybdenum, tungsten, niobium and tantalum do not interfere. PMID:18963014

Donaldson, E M

1981-11-01

169

Androsterone glucuronide is a marker of adrenal hyperandrogenism in hirsute women.  

PubMed

Androsterone glucuronide (Andros-G), a dihydrotestosterone metabolite, is present in serum at concentrations at least tenfold greater than those of androstanediol glucuronide. To investigate the significance of serum androsterone glucuronide, we developed a direct radioimmunoassay for this compound and measured its levels in normal women, women with mild or severe idiopathic hirsutism (IH), hirsute women with polycystic ovarian syndrome (PCO), and non-hirsute obese women. To determine the source of Andros-G precursors, serum levels were measured before and after selective ovarian suppression with leuprolide, combined ovarian and adrenal suppression with leuprolide and dexamethasone, and adrenal stimulation with ACTH. Androsterone glucuronide levels (nmol/l; mean +/- SD) were significantly higher (P less than 0.025) in women with mild idiopathic hirsutism (IH) (185 +/- 91), severe IH (173 +/- 97), and hirsute women with polycystic ovarian syndrome (PCO) (178 +/- 102) than in normal women (110 +/- 26). Levels in non-hirsute obese women (64 +/- 19) were lower than in normal women (P less than 0.01). Baseline levels (mean +/- SEM) in hirsute women given 20 micrograms/kg/day leuprolide for 5-9 months (171 +/- 15) were not significantly changed after leuprolide alone (153 +/- 18), and were decreased after adding dexamethasone (19 +/- 6; P less than 0.001). Andros-G levels did not increase significantly in normal women 60 min after i.v. ACTH (112 +/- 14 to 126 +/- 19), but rose in IH (170 +/- 24 to 216 +/- 26; P less than 0.001) and in PCO (179 +/- 26 to 238 +/- 31; P = 0.002). We conclude that Andros-G in women arises primarily from adrenal gland precursors and is elevated in hirsute women as a group. Its levels do not correlate with the severity of hirsutism, or the presence or absence of PCO, but reflect an increased production of adrenal androgens in both IH and PCO. PMID:2160872

Thompson, D L; Horton, N; Rittmaster, R S

1990-03-01

170

Androgen glucuronides, instead of testosterone, as the new markers of androgenic activity in women.  

PubMed

Despite the long series of cohort studies performed during the last 20 years, the correlation between serum testosterone and any clinical situation believed to be under androgen control in women has remained elusive. This is likely related to the recent finding that the androgens made locally in large amounts in peripheral tissues from the precursor dehydroepiandrosterone (DHEA) act in the same cells where synthesis takes place and are not released in significant amounts in the circulation, thus making unreliable the measurement of serum testosterone as marker of total androgenic activity. The objective is to determine if serum androgen glucuronides can be replaced by testosterone or another steroid as measure of androgenic activity. Since the glucuronide derivatives of androgens are the obligatory route of elimination of all androgens, these metabolites were measured by liquid chromatography tandem mass spectrometry under basal conditions in 377 healthy postmenopausal women aged 55-65 years as well as in 47 premenopausal women aged 30-35 years while testosterone was assayed by gas chromatography mass spectrometry. No correlation was found between the serum concentration of testosterone and that of androsterone glucuronide (ADT-G) or androstenediol glucuronide (3alpha-diol-G), the androgen metabolites which account for the total pool of androgens. The present data show that measurement of the total pool of androgens reflected by the serum levels of ADT-G and 3alpha-diol-G cannot be replaced by serum testosterone or any other steroid, including DHEA or DHEA sulphate. These findings may have implications for women with androgen deficiency involving osteoporosis, obesity, type 2 diabetes, sexual dysfunction, loss of muscular strength and a series of other clinical situations affecting women's health. Measuring ADT-G and 3alpha-diol-G might identify cases of true androgen deficiency and provide an opportunity to offer appropriate androgen therapy. PMID:16621522

Labrie, Fernand; Bélanger, Alain; Bélanger, Patrick; Bérubé, René; Martel, Céline; Cusan, Leonello; Gomez, José; Candas, Bernard; Castiel, Isabelle; Chaussade, Véronique; Deloche, Claire; Leclaire, Jacques

2006-04-18

171

Determination of methyl and ethyl esters of methanesulfonic, benzenesulfonic and p-toluenesulfonic acids in active pharmaceutical ingredients by solid-phase microextraction (SPME) coupled to GC\\/SIM-MS  

Microsoft Academic Search

The development, optimization and validation of an extraction method for methyl and ethyl esters of various sulfonic acids is presented. The extraction and determination of these esters in active pharmaceutical ingredients (APIs) was accomplished using solid-phase microextraction coupled to GC\\/MS in the SIM mode. The factors affecting the extraction efficiency are discussed. This method was validated as a limits test

Ivelisse Colón; Stephen M. Richoll

2005-01-01

172

Novel ethyl-derivatization approach for the determination of fluoride by headspace gas chromatography/mass spectrometry.  

PubMed

We report a novel derivatization chemistry for determination of fluoride based on the batch reaction of fluoride ions with triethyloxonium tetrachloroferrate(III) in a closed vessel to yield fluoroethane. Gaseous fluoroethane was readily separated from the matrix, sampled from the headspace, and determined by gas chromatography/mass spectrometry. The method was validated using rainwater certified reference material (IRMM CA408) and subsequently applied to the determination of fluoride in various matrixes, including tap water, seawater, and urine. An instrumental limit of detection of 3.2 ?g/L with a linear range up to 50 mg/L was achieved. The proposed derivatization is a one-step reaction, requires no organic solvents, and is safe, as the derivatizing agent is nonvolatile. Determination of fluoride is affected by common fluoride-complexing agents, such as Al(III) and Fe(III). The effect of large amounts of these interferences was studied, and the adverse effect of these ions was eliminated by use of the method of standard additions. PMID:23215254

Pagliano, Enea; Meija, Juris; Ding, Jianfu; Sturgeon, Ralph E; D'Ulivo, Alessandro; Mester, Zoltán

2012-12-20

173

N-glucuronidation of drugs and other xenobiotics by human and animal UDP-glucuronosyltransferases.  

PubMed

Metabolic disposition of drugs and other xenobiotics includes glucuronidation reactions that are catalyzed by the uridine diphosphate glucuronosyltransferases (UGTs). The most common glucuronidation reactions are O- and N-glucuronidation and in this review, we discuss both, while the emphasis is on N-glucuronidation. Interspecies difference in glucuronidation is another central issue in this review due to its importance in drug development. Accordingly, the available data on glucuronidation in different animals comes mainly from the species that are used in preclinical studies to assess the safety of drugs under development. Both O- and N-glucuronidation reactions are chemically diverse. Different O-glucuronidation reactions are described and discussed, and many drugs that undergo such reactions are indicated. The compounds that undergo N-glucuronidation include primary aromatic amines, hydroxylamines, amides, tertiary aliphatic amines, and aromatic N-heterocycles. The interspecies variability in N-glucuronidation is particularly high, above all when it comes to aliphatic tertiary amines and aromatic N-heterocycles. The N-glucuronidation rates in humans are typically much higher than in animals, largely due to the activity of two enzymes, the extensively studied UGT1A4, and the more recently identified as a main player in N-glucuronidation, UGT2B10. We discuss both enzymes and review the findings that revealed the role of UGT2B10 in N-glucuronidation. PMID:21434773

Kaivosaari, Sanna; Finel, Moshe; Koskinen, Mikko

2011-03-24

174

ETHYL GLUCURONIDE: A BIOMARKER TO IDENTIFY ALCOHOL USE BY HEALTH PROFESSIONALS RECOVERING FROM SUBSTANCE USE DISORDERS  

Microsoft Academic Search

Aims: Physicians recovering from substance-related disorders are usually allowed to return to practice if they agree to remain abstinent from drugs, including alcohol, and to undergo random urine testing. Over 9000 physicians are currently involved in such monitoring programs in the US. To date, it has been difficult to adequately monitor abstinence from alcohol due to the short half- life

GREGORY E. SKIPPER; WOLFGANG WEINMANN; ANNETTE THIERAUF; PATRICK SCHAEFER; GERHARD WIESBECK; JOHN P ALLEN; MICHAEL MILLER; FRIEDRICH MARTIN WURST

175

Inhibitory effect of azole antifungal agents on the glucuronidation of lorazepam using rabbit liver microsomes in vitro.  

PubMed

Azole antifungal agents (azoles) have inhibitory effects on the cytochrome P450. However, the effect of azoles on conjugative metabolism has not been given much attention. Lorazepam (LZP), a benzodiazepine sedative agent, is known to be metabolized by uridine 5'-diphosphate (UDP)-glucuronyltransferase. Herein we report investigation of the effect of azoles on the enzyme-kinetics of glucuronidation of lorazepam using rabbit liver microsomes in vitro. The Km and Vmax for LZP glucuronidation were determined to be 0.26+/-0.08 mM and 1.25+/-0.21 nmol/min/mg protein, respectively, when evaluated in the presence of a detergent 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate (CHAPS) (0.8 mg/mg protein). Azoles fluconazole, miconazole, and ketoconazole competitively inhibited the glucuronidation of LZP, with Ki values of 7.17+/-4.78 mM, 0.17+/-0.08 mM, and 0.092+/-0.026 mM, respectively. These results are comparable to the previously reported Ki values of azoles with zidovudine (AZT) glucuronidation (1.4, 0.18, and 0.08 mM for fluconazole, miconazole, and ketoconazole, respectively) [Sampol et al., Br. J. Clin. Pharmacol., 40, 83-86, 1995]. Therefore, in order to avoid possible side effects of LZP, the concomitant administration of LZP and azoles should be carefully evaluated. PMID:10823688

Sawamura, R; Sato, H; Kawakami, J; Iga, T

2000-05-01

176

Testosterone sulphation and glucuronidation in the human liver: interindividual variability.  

PubMed

Presystemic sulphation and glucuronidation at OH-C17 limits the bioavailability of testosterone; the aim of this investigation was to describe the variability in testosterone sulphation and glucuronidation rates in the human liver. Liver samples were obtained from 61 women and 40 men of similar age (mean 53 and 55 years, respectively) submitted to surgery. The mean rate of testosterone sulphation was significantly (P = 0.002) higher in men (22.4 pmol/min/mg) than in women (17.5 pmol/min/mg), was not age-dependent, followed bimodal distribution and varied over 7-fold in men and women. There was a weak, but significant negative correlation (r = -0.380; P = 0.003), between the rate of testosterone glucuronidation and age in the liver of women but not in that of men. The mean rate (pmol/min/mg) of testosterone glucuronidation was 155 (men) and 105 (women) (NS) and varied over 20-fold. When the rate of testosterone glucuronidation was expressed on the basis of g liver equivalent, the mean estimates were significantly (P = 0.003) greater in men (3323 pmol/min/g) than in women (1841 pmol/min/g). The present findings are consistent with the view that the hepatic activities of sulphotransferase and glucuronosyltransferase are higher in men than in women and that they vary in the human liver. PMID:9358207

Pacifici, G M; Gucci, A; Giuliani, L

177

Simultaneous Quantification of Buprenorphine, Norbuprenorphine, Buprenorphine-Glucuronide and Norbuprenorphine-Glucuronide in Human Umbilical Cord by Liquid Chromatography Tandem Mass Spectrometry  

PubMed Central

A LCMS method was developed and validated for the simultaneous determination of buprenorphine (BUP), norbuprenorphine (NBUP), buprenorphine glucuronide (BUP-Gluc) and norbuprenorphine glucuronide (NBUP-Gluc) in human umbilical cord. Quantification was achieved by selected ion monitoring of precursor ions m/z 468.4 for BUP; 414.3 for NBUP; 644.4 for BUP-Gluc and 590 for NBUP-Gluc. BUP and NBUP were identified by MS2, with m/z 396, 414 and 426 for BUP, and m/z 340, 364 and 382 for NBUP. Glucuronide conjugates were identified by MS3 with m/z 396 and 414 for BUP-Gluc and m/z 340 and 382 for NBUP-Gluc. The assay was linear 1–50 ng/g. Intra, inter-day and total assay imprecision (%RSD) were <14.5%, and analytical recovery ranged from 94.1% to 112.3% for all analytes. Extraction efficiencies were >66.3%, and process efficiency >73.4%. Matrix effect ranged, in absolute value, from 3.7% to 27.4% (CV<21.8%, n=8). The method was selective with no endogenous or exogenous interferences from 41 compounds evaluated. Sensitivity was high with limits of detection of 0.8 ng/g. In order to prove method applicability, an authentic umbilical cord obtained from an opioid-dependent pregnant woman receiving BUP pharmacotherapy was analyzed. Interestingly, BUP was not detected but concentrations of the other metabolites were NBUP-Gluc 13.4 ng/g, BUP-Gluc 3.5 ng/g and NBUP 1.2 ng/g.

Concheiro, Marta; Shakleya, Diaa M.; Huestis, Marilyn A.

2009-01-01

178

Determination of methyltin compounds in urine of occupationally exposed and general population by in situ ethylation and headspace SPME coupled with GC-FPD.  

PubMed

A method for the determination of methyltin compounds in human urine samples was developed using headspace solid-phase microextration (HS-SPME) coupled with gas chromatographic separation and flame photometric detection. Three methyltin compounds, monomethyltin (MMT), dimethyltin (DMT), and trimethyltin (TMT) were in situ ethylated by sodium tetraethylborate (NaBEt(4)) for SPME and GC-FPD analysis. Under the optimized condition, the detection limits of MMT, DMT, and TMT were 8.1, 2.5 and 5.6 ng Sn L(-1), and the relative standard deviations were 11.0%, 7.3% and 4.0%, respectively. Methyltin compounds in thirteen urine samples from occupationally exposed population and two from general population were analyzed by the proposed method. The concentrations of total methyltin in the tested urine samples of occupationally exposed population ranged from 26.0 to 7892 ng Sn L(-1), and the average level is higher than those of the two non-occupationally exposed individuals. The methyltins in urine were adjusted by osmolality in order to enhance the comparability of different urine samples and the feasibility of this correction method was validated. PMID:21726734

Cui, Zongyan; Zhang, Kegang; Zhou, Qunfang; Liu, Jiyan; Jiang, Guibin

2011-05-13

179

Single-laboratory validation and uncertainty analysis of 82 pesticides determined in pomegranate, apple, and orange by ethyl acetate extraction and liquid chromatography/tandem mass spectrometry.  

PubMed

Single-laboratory validation results are reported for the multiresidue determination of 82 pesticides at < or = 10 ng/g levels in pomegranate, apple, and orange. Samples were extracted with ethyl acetate, and the extracts were cleaned up by dispersive solid-phase extraction with primary secondary amine sorbent. The concentrations of the pesticides were estimated within 18 min of chromatographic run time by liquid chromatography/mass spectrometry with multiple-reaction monitoring. The method was reproducible (HorRat of < 0.5 at 10 ng/g) with measurement uncertainties of < 15% for all the compounds at 10 nglg in all 3 matrixes. The limits of quantitation ranged from 2.5 to 5.0 ng/g with recoveries of 70-120% for most pesticides. Matrix-induced signal suppressions were significantly higher in orange compared with those in pomegranate and apple. The method offers a less expensive and safer alternative to the existing multiresidue analysis methods for fruits and vegetables. PMID:19202806

Banerjee, Kaushik; Oulkar, Dasharath P; Patil, Shubhangi B; Patil, Sangram H; Dasgupta, Soma; Savant, Rahul; Adsule, Pandurang G

180

[Determination of carfentrazone-ethyl(F8426) residue in soil and wheat by wide-bore capillary gas chromatography].  

PubMed

An efficient method for determining F8426 of Affinity 40 DF in soil and wheat is described. F8426 was extracted from the soil and the wheat sample with acetone-water (80:20, volume ratio), and the extract was partitioned with petroleum ether. Then the upper layer was concentrated and cleaned up on a micro-column of Florisil and activated carbon mixture. Finally F8426 was separated from other interfering components through wide-bore capillary gas chromatographic column (OV-1701, 12 m x 0.53 mm i.d.), and was detected by electron capture detector (ECD). The lowest detection limit for F8426 was 0.02 ng. The lowest detectable concentrations in wheat and soil was 2 micrograms/kg and 1 microgram/kg respectively. The average recovery and coefficient of variation of this method were 89.60%-97.53% and 4.42%-8.67% respectively. This method is simple, sensitive and suitable for residue analysis of F8426. PMID:12545479

Han, L J; Qian, C F; Zhang, H

2001-11-01

181

A high throughput assay for the glucuronidation of 7-hydroxy-4-trifluoromethylcoumarin by recombinant human UDP-glucuronosyltransferases and liver microsomes.  

PubMed

Abstract 1.? UDP-glucuronosyltransferases (UGTs) are versatile and important conjugation enzymes in the metabolism of drugs and other xenobiotics. 2.? We have developed a convenient quantitative multi-well plate assay to measure the glucuronidation rate of 7-hydroxy-4-trifluoromethylcoumarin (HFC) for several UGTs. 3.? We have used this method to screen 11 recombinant human UGTs for HFC glucuronidation activity and studied the reaction kinetics with the most active enzymes. We have also examined the HFC glucuronidation activity of liver microsomes from human, pig, rabbit and rat. 4.? At a substrate concentration of 20?µM, the most active HFC glucuronidation catalysts were UGT1A10 followed by UGT1A6 >UGT1A7 >UGT2A1, whereas at 300?µM UGT1A6 was about 10 times better catalyst than the other recombinant UGTs. The activities of UGTs 1A3, 1A8, 1A9, 2B4 and 2B7 were low, whereas UGT1A1 and UGT2B17 exhibited no HFC glucuronidation activity. UGT1A6 exhibited a significantly higher Vmax and Km values toward both HFC and UDP-glucuronic acid than the other UGTs. 5.? Human, pig and rabbit, but not rat liver microsomes, catalyzed HFC glucuronidation at high rates. 6.? This new method is particularly suitable for fast activity screenings of UGTs 1A6, 1A7, 1A10 and 2A1 and HFC glucuronidation activity determination from various samples. PMID:23551063

Rahikainen, Tuomas; Häkkinen, Merja R; Finel, Moshe; Pasanen, Markku; Juvonen, Risto O

2013-04-03

182

Non-steroidal anti-inflammatory drugs interact with testosterone glucuronidation  

Microsoft Academic Search

Testosterone and epitestosterone are secreted mainly as glucuronide metabolites and the urinary ratio of testosterone glucuronide to epitestosterone glucuronide, often called T\\/E, serves as a marker for possible anabolic steroids abuse by athletes. UDP-glucuronosyltransferase (UGT) 2B17 is the most important catalyst of testosterone glucuronidation. The T\\/E might be affected by drugs that interact with UGT2B17, or other enzymes that contribute

Taina Sten; Moshe Finel; Birgitta Ask; Anders Rane; Lena Ekström

2009-01-01

183

Regioselective and Stereospecific Glucuronidation of trans- and cis-Resveratrol in Human  

Microsoft Academic Search

Resveratrol (3,5,4?-trihydroxy-trans-stilbene) is a polyphenol present in wine, which has been reported to have anti-inflammatory, anti-platelet, and anti-carcinogenic effects. The glucuronidation of this compound and that of the cis-isomer also naturally present, has been investigated in human liver microsomes. Both isomers were actively glucuronidated. The reaction led to the formation of two glucuronides (3-O- and 4?-O-glucuronides), whose structure was characterized

Virginie Aumont; Stéphanie Krisa; Eric Battaglia; Patrick Netter; Tristan Richard; Jean-Michel Mérillon; Jacques Magdalou; Nicole Sabolovic

2001-01-01

184

[Determination of acetone, methanol, and methyl ethyl ketone in urine using head-space gas chromatography (HS.GC)].  

PubMed

Using HS.GC, We have succeeded in simultaneous determination of Ac, MeOH and MEK in urine without any complicated pretreatment or correction by internal standard. Moreover, in order to lower the detection limits of these materials, study was made on the salting out effect using 14 kinds of salts. As pretreatment, 2.0 ml of urine, 3.0 g of sodium sulfate and small sized magnetic stirrer are put into vial, which is sealed by septum. This is then heated for 10 min in warm bath of 50 degrees C. In order to dissolve the added salts as much as possible, the specimen is stirred by the stirrer. After cooling the liquid to room temperature, the specimen is analysed by HS.GC. The results showed that sodium sulfate was excellent synthetically. 1) Using the urine of workers not exposed to organic solvents three kinds of urine having specific gravity of 1.010, 1.024 and 1.034 were prepared and mixed standard organic solvents (Ac, MeOH and MEK) were added. Recovery percentages and coefficients of variation were calculated. The results showed that recovery percentages ranged from 92.0 to 101.7% and coefficients of variation from 0.2 to 4.6%. 2) The regression equations of standard curves were satisfactory with y = 9053x - 200(r = 0.999, n = 12) for Ac, y = 801x - 400 (r = 0.999, n = 12) for MeOH, and y = 15488x - 277 (r = 0.999, n = 12) for MEK. 3) The detection limits calculated by IUPAC formula were 0.0092 mg/l for Ac, 0.11 mg/l for MeOH and 0.0063 mg/l for MEK. These results indicated that this method is superior to other methods because the pretreatment is very simple, specificity is excellent, analysis by standard curves is possible, and this method is not affected by specific gravity of the urine. PMID:1619800

Michitsuji, H; Ohara, A; Fukuda, M; Nakayama, K; Yamaguchi, K; Fujiki, Y

1992-05-01

185

Glucuronidation of the mycotoxins alternariol and alternariol-9-methyl ether in vitro: chemical structures of glucuronides and activities of human UDP-glucuronosyltransferase isoforms.  

PubMed

Alternariol (AOH) and alternariol-9-methyl ether (AME) are major toxins produced by fungi of the genus Alternaria and are frequently found in various food items. Because AOH has three hydroxyl groups and AME two, the formation of various glucuronides must be expected. When AOH was incubated with hepatic and intestinal microsomes from rats, pigs and humans in the presence of uridine diphosphate glucuronic acid, two glucuronides were detected and tentatively identified as AOH-3-O-glucuronide and AOH-9-O-glucuronide. Under the same conditions, AME yielded predominantly AME-3-O-glucuronide and only small amounts of AME-7-O-glucuronide. The activities of all microsomes for the glucuronidation of AOH and AME were in the same range. Nine out of ten recombinant human UDP-glucuronosyltransferases (UGTs) were able to glucuronidate AOH, and eight out of ten UGTs had activity for AME. These data suggest that AOH and AME are readily glucuronidated in hepatic and extrahepatic tissues, implying that glucuronidation constitutes a major metabolic pathway in the disposition of these mycotoxins. PMID:23604930

Pfeiffer, E; Schmit, C; Burkhardt, B; Altemöller, M; Podlech, J; Metzler, M

2008-12-23

186

Validation of benzodiazepine ?-glucuronide primary reference materials for hydrolysis and quality assurance controls  

Microsoft Academic Search

The major metabolite of hydroxylated benzodiazepines is the ?-glucuronide metabolite, thus a hydrolysis step is included in benzodiazepine analyses in urine. We evaluated the new Alltech (R,S) oxazepam and lorazepam ?-glucuronide primary reference materials as hydrolysis controls and for use in proficiency testing. Using HPLC analysis and GC\\/MS analysis following acid and ?-glucuronidase hydrolysis, we found that the lorazepam ?-glucuronide

Carol L. O'Neal; Alphonse Poklis

1996-01-01

187

Effect of butylated hydroxyanisole on hepatic glucuronidation and biliary excretion of drugs in mice.  

PubMed

Inhibition of glucuronidation by depletion of UDP-glucuronic acid from liver impairs the hepatobiliary transport of glucuronidated xenobiotics. However, it is not known if enhancement of hepatic glucuronidation increases the biliary excretion of these compounds. Therefore, the effect of treatment with butylated hydroxyanisole (BHA), which increases hepatic glucuronidation capacity, on the biliary excretion of compounds undergoing glucuronidation was studied in mice. BHA-feeding (1% for 10 days) increased hepatic UDP-glucuronic acid content by 240% and enhanced hepatic UDP-glucuronosyltransferase activities (expressed per kg body weight) toward valproic acid, phenolphthalein, iopanoic acid and bilirubin 220, 180, 120 and 60%, respectively. BHA treatment did not influence the biliary excretion of unmetabolized cholephils, phenol-3,6-dibromphthalein disulphonate and phenolphthalein glucuronide, but enhanced that of phenolphthalein (+108%), iopanoic acid (+63%) and bilirubin (+33%) as glucuronides. However, these increases were apparent only in the initial phase of excretion. In contrast, BHA markedly decreased (-43%) the biliary excretion of valproic acid glucuronides. Simultaneously, BHA increased the urinary excretion of the glucuronides of phenolphthalein (+48%), iopanoic acid (+450%) and valproic acid (+150%). A shift in the distribution of iopanoic acid and valproic acid and metabolites from liver to kidney was also apparent in BHA-fed mice. Thus, enhanced glucuronidation does not facilitate the biliary excretion of all glucuronidated compounds and only transiently increases others. It is likely that this phenomenon is the result of the glucuronides readily entering the plasma and being excreted by the kidney. PMID:2900301

Gregus, Z; Klaassen, C D

1988-04-01

188

New Spectrophotometric Method for Determining Nitrogen Dioxide in Air Using 2,2-azino-bis(3-ethyl benzothiazoline)-6-Sulfonic Acid-Diammonium Salt and Passive Sampling  

PubMed Central

A new simple and highly sensitive spectrophotometric method for determining nitrogen dioxide in air was developed. The method is based on converting atmospheric nitrogen dioxide to nitrite ions within the IVL passive samplers used for samples collection. Acidifying nitrite ions with concentrated HCl produced the peroxynitrous acid oxidizing agent which was measured using 2, 2-azino-bis(3-ethyl benzothiazoline)-6-sulfonic acid-diammonium salt (ABTS) as reducing coloring agent. A parallel series of collected samples were measured for its nitrite content using a validated ion chromatographic method. The results obtained using both methods were compared in terms of their sensitivity and accuracy. Developed spectrophotometric method was shown to be one order of magnitude higher in sensitivity compared to the ion chromatographic method. Quantitation limits of 0.05 ppm and 0.55 ?g/m3 were obtained for nitrite ion and nitrogen dioxid, respectively. Standard deviations in the ranges of 0.05–0.59 and 0.63–7.92 with averages of 0.27 and 3.11 were obtained for determining nitrite and nitrogen dioxide, respectively. Student-t test revealed t-values less than 6.93 and 4.40 for nitrite ions and nitrogen dioxide, respectively. These values indicated insignificant difference between the averages of the newly developed method and the values obtained by ion chromatography at 95% confidence level. Compared to continuous monitoring techniques, the newly developed method has shown simple, accurate, sensitive, inexpensive and reliable for long term monitoring of nitrogen dioxide in ambient air.

Salem, Alaa A.; Soliman, Ahmed A.; El-Haty, Ismail A.

2011-01-01

189

Fatty acid ethyl ester concentrations in hair and self-reported alcohol consumption in 644 cases from different origin  

Microsoft Academic Search

For diagnosis of chronic alcohol abuse, fatty acid ethyl esters (FAEE) were determined in hair samples from 644 individuals, mainly parents from child protection cases. The analysis for ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate was performed according to a validated procedure consisting of external degreasing by two times washing with n-heptane, extraction with a mixture of dimethylsulfoxide

Silke Süße; Carl M. Selavka; Tom Mieczkowski; Fritz Pragst

2010-01-01

190

Multiple headspace solid-phase microextraction after matrix modification for avoiding matrix effect in the determination of ethyl carbamate in bread.  

PubMed

This study presents the potential of multiple headspace solid-phase microextraction (multiple HS-SPME) for the quantification of analytes in solid samples. Multiple HS-SPME shares the same advantages as SPME. It also enables a complete recovery of the target compound and therefore the matrix effect, which commonly appears in SPME-based analysis, is avoided. A method based on multiple HS-SPME for the determination of the toxic contaminant ethyl carbamate (EC) in bread samples has been developed and validated, using gas chromatography with flame ionization detector. A novel polyethylene glycol/hydroxy-terminated silicone oil fiber was prepared for the first time and subsequently used instead of commercial ones because of its high extraction ability and good operational stability. An important problem still remained in multiple HS-SPME of EC in fresh bread samples. The adsorption of EC by water in the samples caused low transport of analyte to the headspace, which made multiple HS-SPME invalidated. Mixing with anhydrous sodium sulphate, the sensitivity of the method was improved and the problem was solved. The proposed method showed satisfactory linearity (0.15-1500 ?g g(-1)), precision (1.6%, n=5) and limit of detection (0.041 ?g g(-1)). Good recoveries, from 92.5 to 103.4%, were observed at three spiking levels. The method was applied to 14 bread samples. The multiple HS-SPME technique offers several advantages including reducing the manipulation time and cost, and avoiding analyte losses, especially in the analysis of a large number of samples in different matrices. PMID:22123114

Ye, Chang-Wen; Zhang, Xue-Na; Gao, Yuan-Li; Wang, Yu-Long; Pan, Si-Yi; Li, Xiu-Juan

2011-11-03

191

Microwave-assisted extraction and accelerated solvent extraction with ethyl acetate-cyclohexane before determination of organochlorines in fish tissue by gas chromatography with electron-capture detection.  

PubMed

Focused open-vessel microwave-assisted extraction (FOV-MAE), closed-vessel microwave-assisted extraction (CV-MAE), and accelerated solvent extraction (ASE) were used for extraction before determination of organochlorine compounds (polychlorinated biphenyls, DDT, toxaphene, chlordane, hexachlorobenzene, hexachlorocyclohexanes, and dieldrin) in cod liver and fish fillets. Wet samples were extracted without the time-consuming step of lyophilization or other sample-drying procedures. Extractions were performed with the solvent mixture ethyl acetate-cyclohexane (1 + 1, v/v), which allowed direct use of gel-permeation chromatography without solvent exchange. For FOV-MAE, the solvent mixture removed water from the sample matrix via azeotropic distillation. The status of water removal was controlled during extraction by measuring the temperature of the distillate. After water removal, the temperature of the distillate increased and the solvent mixture became less polar. Only the pure extraction solvent allowed quantitative extraction of the organochlorine compounds. For CV-MAE, water could not be separated during the extraction. For this reason, the extraction procedure for wet fish tissue required 2 extraction steps: the first for manual removal of coextracted water, and the second for quantitative extraction of the organochlorine compounds with the pure solvent. Therefore, CV-MAE is less convenient for samples with high water content. For ASE, water in the sample was bound with Na2SO4. The reproducibility for each technique was very good (relative standard deviation was typically <10%); the slightly varying levels were attributed to deviations during sample cleanup and the generally low levels. PMID:11128135

Weichbrodt, M; Vetter, W; Luckas, B

192

Forensic confirmatory analysis of ethyl sulfate—A new marker for alcohol consumption—by liquid-chromatography\\/electrospray ionization\\/tandem mass spectrometry  

Microsoft Academic Search

Ethyl sulfate (EtS)—a new direct marker for ethanol intake besides ethyl glucuronide (EtG) and others—was detected in urine\\u000a samples by electrospray ionization tandem mass-spectrometry (LC-ESI-MS\\/MS). Ethyl sulfate sodium salt was used for method\\u000a development, yielding a precursor [M?H]?\\u000a m\\/z 125 and product ions m\\/z 97 [HSO4]? and m\\/z 80 [SO3]?. Pentadeuterated EtS (D5-EtS) was synthesized by esterification of sulfuric acid

Sebastian Dresen; Wolfgang Weinmann; Friedrich Martin Wurst

2004-01-01

193

Resveratrol Is Absorbed in the Small Intestine as Resveratrol Glucuronide  

Microsoft Academic Search

We have studied the absorption and metabolism of resveratrol in the jejunum in an isolated rat small intestine model. Only small amounts of resveratrol were absorbed across the enterocytes of the jejunum and ileum unmetabolised. The major compound detected on the serosal side was the glucuronide conjugate of resveratrol (96.5% ± 4.6 of the amount absorbed) indicating the susceptibility of

Gunter Kuhnle; Jeremy P. E. Spencer; George Chowrimootoo; Hagen Schroeter; Edward S. Debnam; S. Kaila S. Srai; Catherine Rice-Evans; Ulrich Hahn

2000-01-01

194

Enzymatic synthesis of glucuronides using lipophilic hollow fiber membranes  

Microsoft Academic Search

A lipophilic hollow fiber membrane preparation was used for the enzymatic glucuronidation of lipophilic aromatic compounds. A crude solubilized microsomal enzyme preparation was circulated on the external side of the lipophilic membrane while the phenol containing buffer solution was circulated through the internal side of the hollow fiber membrane. Phenols, which accumulate in and penetrate the lipophilic membrane, were converted

F. Tegtmeier; K. Belsner; G. Brunner

1988-01-01

195

Flow-injection conductometric determination of acidity in industrial hydrated ethyl alcohol 1 Presented at the VII International Conference on Flow Analysis, held at Piracicaba, SP., Brazil, August 25–28, 1997. 1  

Microsoft Academic Search

A flow-injection (FI) conductometric procedure is proposed for the determination of acidity in industrial 96% v\\/v hydrated ethyl alcohol. The method consists in a single-line system in which an alkaline solution (sodium hydroxide), in excess, is used as carrier. When the sample is inserted in the flow system, it mixes with and partially neutralizes the carrier solution, causing a decrease

Orlando Fatibello-Filho; Maria Teresa Mendes Ribeiro Borges

1998-01-01

196

21 CFR 584.200 - Ethyl alcohol containing ethyl acetate.  

Code of Federal Regulations, 2010 CFR

The feed additive ethyl alcohol containing ethyl acetate meets the requirement of 27 CFR 21.62, being not less than 92.5 percent ethyl alcohol, each 100 gallons having had added the equivalent of 4.25 gallons of 100 percent ethyl...

2009-04-01

197

Transport of 7Ethyl10-hydroxycamptothecin (SN38) by Breast Cancer Resistance Protein ABCG2 in Human Lung Cancer Cells  

Microsoft Academic Search

Overexpression of breast cancer resistance protein (BCRP) ABCG2 reportedly confers cancer cell resistance to camptothecin-based anticancer drugs, such as topotecan and 7-ethyl-10-hydroxycamptothecin (SN-38: the active metabolite of irinotecan). We have recently shown that SN-38-selected PC-6\\/SN2-5H human lung carcinoma cells overexpressed BCRP with the reduced intracellular accumulation of SN-38 and SN-38-glucuronide (S. Kawabata et al., Biochem. Biophys. Res. Commun. 280, 1216–1223,

Katsumi Nakatomi; Megumi Yoshikawa; Mikio Oka; Yoji Ikegami; Shinya Hayasaka; Kazumi Sano; Ken Shiozawa; Shigeru Kawabata; Hiroshi Soda; Toshihisa Ishikawa; Shinzo Tanabe; Shigeru Kohno

2001-01-01

198

Analysis of bile acid glucuronides in urine: group separation on a lipophilic anion exchanger.  

PubMed

A chromatographic separation of glucuronidated bile acids using the anion exchanger diethylaminohydroxypropyl Sephadex LH-20 (DEAP LH-20) is described. Group separation of non-sulfated, non-glucuronidated bile acids, bile acid glucuronides, bile acid monosulfates, and bile acid disulfates was obtained. The method allowed analysis of all these bile acid derivatives in the urine of 15 patients with cirrhosis of the liver and cholestasis. The patients excreted in mean 30.4 mumol/24 h non-sulfated, non-glucuronidated bile acids, 90.3 mumol bile acid monosulfates, and 10.2 mumol bile acid glucuronides. Glycine- or taurine-conjugated were 68% of the non-sulfated, non-glucuronidated bile acids, 96% of bile acid sulfates, and 81% of bile acid glucuronides. PMID:7116646

Stiehl, A; Raedsch, R; Rudolph, G; Czygan, P; Walker, S

1982-08-18

199

Regioselective glucuronidation of denopamine: marked species differences and identification of human udp-glucuronosyltransferase isoform.  

PubMed

Denopamine is one of the oral beta(1)-adrenoceptor-selective partial agonists. Denopamine glucuronide is the most abundant metabolite in human, rat, and dog urine when administered orally. Species differences in denopamine glucuronidation were investigated with liver microsomes obtained from humans and experimental animals. In rat and rabbit, only the phenolic glucuronide was detected, whereas in dog and monkey, not only the phenolic glucuronide but also the alcoholic glucuronide was found. In contrast, in humans, the alcoholic glucuronide was detected exclusively. The kinetics of denopamine glucuronidation in human liver microsomes showed a typical Michaelis-Menten plot. The K(m) and V(max) values accounted for 2.87 +/- 0.17 mM and 7.29 +/- 0.23 nmol/min/mg protein, respectively. With the assessment of denopamine glucuronide formation across a panel of recombinant UDP-glucuronosyltransferase (UGT) isoforms (UGT1A1, UGT1A3, UGT1A4, UGT1A6, UGT1A7, UGT1A8, UGT1A9, UGT1A10, UGT2B4, UGT2B7, UGT2B15, and UGT2B17), only UGT2B7 exhibited high denopamine glucuronosyltransferase activity. The K(m) value of denopamine glucuronidation in recombinant UGT2B7 microsomes was close to those in human liver and jejunum microsomes. The formation of denopamine glucuronidation by human liver, jejunum, and recombinant UGT2B7 microsomes was effectively inhibited by diclofenac, a known substrate for UGT2B7. The denopamine glucuronidation activities in seven human liver microsomes were significantly correlated with diclofenac glucuronidation activities (r(2) = 0.685, p < 0.05). These results demonstrate that the denopamine glucuronidation in human liver and intestine is mainly catalyzed by UGT2B7 and that glucuronidation of the alcoholic hydroxyl group, but not the phenolic hydroxyl group, occurs regioselectively in humans. PMID:15608137

Kaji, Hidefumi; Kume, Toshiyuki

2004-12-17

200

Simple measurement of gluconeogenesis by direct2H NMR analysis of menthol glucuronide enrichment from2H2O  

Microsoft Academic Search

The contribution of gluconeogenesis to fasting glucose produc- tion was determined by a simple measurement of urinary men- thol glucuronide (MG) 2H enrichment from 2H2O. Following in- gestion of 2H2O (0.5% body water) during an overnight fast and a pharmacological dose (400 mg) of a commercial peppermint oil preparation the next morning, 364 mol MG was quantita- tively recovered from

Angela Ribeiro; M. Madalena Caldeira; Manuela Carvalheiro; Margarida Bastos; Carla Baptista; Ana Fagulha; Luisa Barros; Cristina Barosa; John G. Jones

2005-01-01

201

Androstanediol glucuronide isomers in normal men and women and in men infused with labeled dihydrotestosterone  

SciTech Connect

3 alpha-Androstanediol glucuronide (Adiol G) is a major metabolite of dihydrotestosterone (DHT). Adiol G actually represents 2 different compounds, since the glucuronide can be conjugated at the 3-carbon position (Adiol 3-G) or at the 17-carbon position (Adiol 17-G). To determine which glucuronide represents the predominant physiological DHT metabolite and which isomer is the major circulating form, we developed a RIA to directly measure Adiol 3-G in serum extracts. In 10 normal men, mean serum Adiol 3-G and total Adiol G levels were 4.44 +/- 0.49 (+/- SE) nmol/L (208 +/- 23 ng/dL) and 27.9 +/- 2.8 nmol/L (1310 +/- 129 ng/dL), respectively (13.9 +/- 3.0% of Adiol G was Adiol 3-G). In 10 normal women sampled during the early follicular phase, mean serum Adiol 3-G and total Adiol G levels were 2.64 +/- 0.64 nmol/L (124 +/- 30 ng/dL) and 14.9 +/- 1.5 nmol/L (697 +/- 69 ng/dL), respectively (17.4 +/- 3.6% of Adiol G was Adiol 3-G). In 4 normal men infused for 8 h with tritiated DHT, 17.4 +/- 3.4% of the resulting tritiated Adiol G was Adiol 3-G. These results indicate that Adiol 17-G is the predominant circulating form of Adiol G in normal men and women and that it is also the major Adiol G isomer derived from DHT.

Rittmaster, R.S.; Thompson, D.L.; Listwak, S.; Loriaux, D.L.

1988-01-01

202

Urinary metabolic profile of 19-norsteroids in humans: glucuronide and sulphate conjugates after oral administration of 19-nor-4-androstenediol.  

PubMed

19-Nor-4-androstenediol (NOL) is a prohormone of nandrolone (ND). Both substances are included in the WADA List of Prohibited Classes of Substances and their administration is determined by the presence of 19-norandrosterone (NA) with the urinary threshold concentration of 2 ng mL(-1). Routine analytical procedures allow the determination of NA excreted free and conjugated with glucuronic acid, but amounts of ND and NOL metabolites are also excreted in the sulphate fraction. The aim of this study is to determine the urinary metabolic profile after oral administration of a nutritional supplement containing NOL. Urine samples were collected up to 96 h following supplement administration and were extracted to obtain separately three metabolic fractions: free, glucuronide and sulphate. Extraction with tert-butyl methyl ether was performed after the hydrolysis steps and trimethylsilyl derivatives were analyzed by gas chromatography/mass spectrometry (GC/MS). After oral administration of NOL, the main metabolites detected were NA and noretiocholanolone (NE) in the glucuronide and sulphate fractions. The relative abundances of each metabolite in each fraction fluctuate with time; a few hours after administration the main metabolite was NA glucuronide whereas in the last sample (4 days after administration) the main metabolite was the NA sulphate and the second was the NE glucuronide. During the studied period almost half of the dose was excreted and the main metabolites were still found in urine after 96 h. Norepiandrosterone and norepietiocholanolone were also detected only in the sulphate fraction. Our results suggest that sulphate metabolites should be taken into consideration in order to increase the retrospectivity in the detection of 19-norsteroids after oral administration. PMID:18763272

Torrado, Susana; Roig, Meritxell; Farré, Magi; Segura, Jordi; Ventura, Rosa

2008-10-01

203

Drug and xenobiotic glucuronidation catalysed by cloned human liver UDP-Glucuronosyltransferases stably expressed in tissue culture cell lines.  

PubMed

Two human UDP-Glucuronosyltransferase (UGT) cDNA clones were stably integrated into V79 chinese hamster fibroblast cells and the functional enzymes were expressed in this heterologous environment. More than 100 drugs and xenobiotics were used as substrates for glucuronidation, catalysed by the cloned UGTs to determine the chemical structures accepted as substrates. UGT HP1 exhibited a limited specificity for planar phenolic compounds, whereas UGT HP4 was more promiscuous in acceptance of non-planar phenols, anthraquinones, flavones, aliphatic alcohols, aromatic carboxylic acids, steroids and many drugs of varied structure. These conclusions are illustrated here by using a series of alkyl- and halophenols. This work indicates the considerable potential value in use of these recombinant cell lines to study human drug glucuronidation. PMID:8236271

Wooster, R; Ebner, T; Sutherland, L; Clarke, D; Burchell, B

1993-10-01

204

Column-switching reversed phase–hydrophilic interaction liquid chromatography\\/tandem mass spectrometry method for determination of free estrogens and their conjugates in river water  

Microsoft Academic Search

We report a column-switching liquid chromatography (LC) tandem mass spectrometry (MS\\/MS) method for highly sensitive determination of both free estrogens (estrone, estradiol, and estriol) and their conjugates (estrone-3-sulfate, estradiol-3-sulfate, estriol-3-sulfate, estrone-3-glucuronide, estradiol-3-glucuronide, estriol-16-glucuronide, and estriol-3-glucuronide) in river water. This technique combines reversed phase (RP) chromatographic separation of the dansyl chloride derivatized free estrogens and hydrophilic interaction liquid chromatographic (HILIC) separation

Feng Qin; Yuan Yuan Zhao; Michael B. Sawyer; Xing-Fang Li

2008-01-01

205

Studies on the disturbance of glucuronide formation in infectious hepatitis  

Microsoft Academic Search

The ability of the liver to form glucuronides was measured in 10 patients with infectious hepatitis. One test was done at the onset and another about four weeks later after the clinical symptoms had disappeared. N-acetyl-p-aminophenol (N.A.P.A.) or acetanilide was administered in doses ranging from 10 to 20 mg. per kg. body weight, either orally or by intravenous injection. N.A.P.A.

M. F. Vest; E. Fritz

1961-01-01

206

Variation in glucuronidation of lamotrigine in human liver microsomes.  

PubMed

Lamotrigine (LTG), a diaminotriazine anti-epileptic, is principally metabolized at the 2-position of the triazine ring to form a quaternary ammonium glucuronide (LTGG) by uridine glucuronosyl transferease (UGT) 1A3 and UGT1A4. It has been hypothesized that glucuronidation of anti-epileptic drugs is spared with age, despite a known decrease in liver mass, based on older studies with benzodiazepines such as lorazepam. To examine this, the formation rates of LTGG formation were measured by liquid chromatography-mass spectrometry (LC-MS) in a bank of human liver microsomes (HLMs) obtained from younger and elderly donors at therapeutic concentrations. The formation rate of LTGG was not significantly different in HLMs obtained from younger and elderly subjects. A four- to five-fold variation for the formation of LTGG was observed within each microsomal bank obtained from elderly and younger donors, and the range of LTGG formation was observed to be 0.15-0.78 nmoles min(-1) mg(-1) of protein across the entire set of HLMs (n = 36, elderly and younger HLMs). UGT1A4 and UGT1A3 catalysed the formation of LTGG with an intrinsic clearances of 0.28 and 0.02 microl min(-1) mg(-1) protein, respectively. UGT2B7 and UGT2B4 showed no measurable activity. No correlation was observed across the HLM bank for glucuronidation of LTG and valproic acid (a substrate for multiple UGT isoforms including UGT1A4). PMID:19387891

Argikar, U A; Remmel, R P

2009-05-01

207

Synthesis and iodine-125 labelling of glucuronide compounds for combined chemo- and radiotherapy of cancer  

Microsoft Academic Search

Some types of cancer cells have high levels of beta-glucoronidase activity. This enzyme is able to deglucuronidate a variety of glucuronide derivatives on the cell membrane. Either O- or N-glucuronides can be selectively incorporated into the cancer cells. If the aglycone is cytotoxic, the glucuronide can potentially be used as a selective anti-cancer drug in cancers with high levels of

Turan Ünak; Perihan Ünak; Binnur Ongun; Yusuf Duman

1997-01-01

208

GC\\/MS Determination of 11Nor9-Carboxy-?-tetrahydrocannabinol in Urine from Cannabis Users  

Microsoft Academic Search

A new method for detecting and quantifying 11-nor-9-carboxy-?-tetrahydrocannabinol (?-THC-COOH) in urine is proposed. The analyte is released as a glucuronide derivative into urine, so the glucuronide bond must be cleaved by alkaline hydrolysis prior to analysis. Subsequently, the sample is subjected to liquid-liquid extraction with n-hexane\\/ethyl acetate, followed by derivatization with a mixture of pentafluoropropionic anhydride (PFPA) and pentafluoropropanol (PFP-OH).

J. L. Villamor; A. M. Bermejo; M. J. Tabernero; P. Fernández; I. Sánchez

1998-01-01

209

Ethyl alcohol production  

SciTech Connect

Recent price increases and temporary shortages of petroleum products have caused farmers to search for alternate sources of fuel. The production of ethyl alcohol from grain is described and the processes involved include saccharification, fermentation and distillation. The resulting stillage has potential as a livestock feed.

Hofman, V.; Hauck, D.

1980-11-01

210

Enzyme-assisted synthesis and structural characterization of the 3-, 8-, and 15-glucuronides of deoxynivalenol.  

PubMed

4-Deoxynivalenol is one of the most prevalent mycotoxins in grain-based food and feed products worldwide. Conjugation of deoxynivalenol to glucuronic acid and elimination via the urine appears to be the major metabolism pathway, although with differing efficiency in different species. In order to make pure deoxynivalenol glucuronides for analytical methodologies available we intended to enzymatically synthesize glucuronides of deoxynivalenol using rat and human liver microsomes supplemented with uridine 5'-diphosphoglucuronic acid and alamethicin as detergent. Three glucuronides were isolated and purified using solid-phase extraction of microsomal incubations and subsequent semipreparative hydrophilic interaction chromatography. NMR spectra were obtained for all three compounds from solutions in methanol, showing that deoxynivalenol 3-O-?-D-glucuronide and deoxynivalenol 15-O-?-D-glucuronide were the major products from incubations of deoxynivalenol with rat and human liver microsomes, respectively. The NMR spectra of a third glucuronide showed replacement of the C-8 carbonyl by a ketal carbon. This glucuronide was finally identified as deoxynivalenol 8-O-?-D-glucuronide. The present study provides unequivocal structural evidence for three glucuronides of deoxynivalenol formed by liver enzymes. PMID:23374009

Uhlig, Silvio; Ivanova, Lada; Fæste, Christiane Kruse

2013-02-18

211

GRAS Notice 000470: Ethyl cellulose  

Center for Food Safety and Applied Nutrition (CFSAN)

Text Version... Figure 1. Chemical Structure of Ethyl Cellulose ... Given the strong hydrophobic character of ethyl cellulose together with its high molecular mass ... More results from www.fda.gov/downloads/food/ingredientspackaginglabeling

212

Determination of free and esterified cholesterol by a kinetic method. I. The introduction of the enzymatic method with 2,2'-azino-di-3[ethyl-benzthiazolin sulfonic acid (6)] (ABTS).  

PubMed

A new, simple kinetic method is described for the determination of serum cholesterol based on the oxidation of 2,2'-azino-di-3[ethyl-benzthiazolin sulfonic acid (6)] (ABTS) by use of a single aqueous reagent. This assay procedure is rapid, specific, reproducible and applicable to the measurement of free and esterified cholesterol in a continuous procedure. The method requires no prior treatment of sample and linear kinetics are obtained up to 13 mmol/l cholesterol. The use of ABTS permits the direct calculation of cholesterol concentrations from absorbance changes at 410 nm (A = epsilon - c - d). PMID:20250

Majki?, N; Berkes, I

1977-10-01

213

Characterization of Dibenzo[a,l ]pyrene-trans-11,12-diol (Dibenzo[def,p]chrysene) Glucuronidation by UDP-glucuronosyltransferases  

PubMed Central

Dibenzo[a,l]pyrene (DB[a,l]P) (dibenzo[def,p]chrysene) is a highly carcinogenic polycyclic aromatic hydrocarbon (PAH) that has been identified in tobacco smoke and is found in our environment due to incomplete combustion of organic matter. Its metabolites are known to form stable DNA adducts in bacteria and mammalian cells, and can lead to tumors in animal models. Glucuronidation of major metabolites of DB[a,l]P by the uridine-5’-diphosphate glucuronosyltransferase (UGT) family of enzymes is an important route of detoxification of this pro-carcinogen. The focus of the current study was to characterize the glucuronidation of the pro-carcinogenic enantiomers DB[a,l]P-(+)-trans-11S,12S–diol and DB[a,l]P-(?)-trans-11R,12R–diol. Glucuronidation assays with HEK293 cell lines over-expressing individual human UGT enzymes demonstrated that UGTs 1A1, 1A4, 1A7, 1A8, 1A9, 1A10, and 2B7 glucuronidated one or both DB[a,l]P-trans-11,12-diol enantiomers. Three glucuronide conjugates were observed in activity assays with UGTs 1A1 and 1A10, while two glucuronides were formed by UGTs 1A7, 1A8, and 1A9, and one glucuronide was made by UGT1A4 and UGT2B7. Enzyme kinetic analysis indicated that UGT1A9 was the most efficient UGT at forming both the (+)-DB[a,l]P-11-Gluc and (?)-DB[a,l]P-11-Gluc products while UGTs 1A1 and 1A10 were the most efficient at forming the (+)-DB[a,l]P-12-Gluc product (as determined by the kcat/KM). Incubations with human liver microsomes showed formation of three diastereomeric glucuronide products: (+)-DB[a,l]P-11-Gluc, (+)-DB[a,l]P-12-Gluc, and (?)-DB[a,l]P-11-Gluc, with an average overall ratio of 31 : 32 : 37 in four liver specimens. Human bronchus and trachea tissue homogenates demonstrated glucuronidation activity against both DB[a,l]P-trans-11,12-diol enantiomers, with both tissues producing the (+)-DB[a,l]P-11-Gluc and (+)-DB[a,l]P-12-Gluc with little or no formation of (?)-DB[a,l]P-11-Gluc. These results indicate that multiple UGTs are involved in the stereospecific glucuronidation of DB[a,l]P-trans-11,12-diol in a pattern consistent with their expression in respiratory tract tissues, and that glucuronidation may be an important first-line detoxification mechanism of DB[a,l]P metabolites.

Olson, Kristine C.; Sun, Dongxiao; Chen, Gang; Sharma, Arun K.; Amin, Shantu; Ropson, Ira J.; Spratt, Thomas E.; Lazarus, Philip

2011-01-01

214

Stereoselective glucuronidation of ornidazole in humans: predominant contribution of UDP-glucuronosyltransferases 1A9 and 2B7.  

PubMed

Ornidazole [R,S-1-chloro-3-(2-methyl-5-nitro-1H-imidazol-1-yl)propan-2-ol] is a chiral 5-nitroimidazole class antimicrobial agent. This study aimed to investigate the principal metabolic pathway of ornidazole in humans and identify the major enzymes involved. A total of 19 metabolites were identified in human urine collected from patients with hepatobiliary diseases after an intravenous drip infusion of 500 mg of racemic ornidazole. Stereoselective glucuronidation, followed by renal excretion, was the principal metabolic pathway of ornidazole in humans, accounting for 37.3% of the administered dose. Screening assays with 12 available human recombinant UDP-glucuronosyltransferases (UGTs) demonstrated that UGT1A9 was the predominant UGT isoform involved in R-ornidazole glucuronidation, whereas S-ornidazole glucuronidation was almost exclusively catalyzed by UGT2B7. Chemical inhibition study with niflumic acid and flurbiprofen supported these findings. Enzyme kinetic parameters were then determined in human liver microsomes (HLMs), human kidney microsomes (HKMs), UGT1A9, and 2B7. The K(m) values for UGT1A9 (15.6 ± 1.6 mM for R-ornidazole) and 2B7 (3.8 ± 0.9 mM for S-ornidazole) were quite similar to those determined in HLMs and HKMs (20.1 ± 1.4 and 17.7 ± 4.0 mM for R-ornidazole; 6.6 ± 1.3 and 3.2 ± 0.4 mM for S-ornidazole). The in vitro intrinsic clearance (CL(int)) ratios of S- to R-ornidazole were approximately 4.3 in HLMs and 6.5 in HKMs, respectively. The hepatic and renal clearances were estimated based on the well-stirred model. Overall, stereoselective glucuronidation was the principal metabolic pathway of ornidazole in humans. Furthermore, UGT1A9 and 2B7 were the predominant UGT isoforms responsible for R- and S-ornidazole glucuronidation in humans, respectively. PMID:23571427

Du, Jiangbo; You, Tiangeng; Chen, Xiaoyan; Zhong, Dafang

2013-04-09

215

Organochlorines inhibit acetaminophen glucuronidation by redirecting UDP-glucuronic acid towards the D-glucuronate pathway  

SciTech Connect

Industry-derived organochlorines are persistent environmental pollutants that are a continuing health concern. The effects of these compounds on drug metabolism are not well understood. In the current study we present evidence that the inhibition of acetaminophen (APAP) glucuronidation by minute concentrations of organochlorines correlates well with their ability to stimulate the D-glucuronate pathway leading to ascorbate synthesis. A set of 6 arylated organochlorines, including 5 PCB (polychlorinated biphenyl) congeners, were assessed for their effects on APAP glucuronidation in isolated hepatocytes from male Sprague-Dawley rats. The capacity of each organochlorine to inhibit APAP glucuronidation was found to be directly proportional to its capacity to stimulate ascorbate synthesis. PCB153, PCB28 and bis-(4-chlorophenyl sulfone) (BCPS) in increasing order were the most effective organochlorines for inhibiting APAP glucuronidation and stimulating the D-glucuronate pathway. None of the 3 inhibitors of APAP glucuronidation were able to alter the expression of UGT1A6, UGT1A7 and UGT1A8 (the major isoforms responsible for APAP glucuronidation in the rat), however, their efficacy at inhibiting APAP glucuronidation was proportional to their capacity to deplete UDP-glucuronic acid (UDPGA). BCPS-mediated inhibition of APAP glucuronidation in isolated hepatocytes had non-competitive characteristics and was insensitive to the inactivation of cytochrome P450. The effective organochlorines were also able to selectively stimulate the hydrolysis of UDPGA to UDP and glucuronate in isolated microsomes, but could not inhibit APAP glucuronidation in microsomes when UDPGA was in excess. We conclude that organochlorines are able to inhibit APAP glucuronidation in hepatocytes by depleting UDPGA via redirecting UDPGA towards the D-glucuronate pathway. Because the inhibition is non-competitive, low concentrations of these compounds could have long term inhibitory effects on the glucuronidating capacity of hepatocytes.

Chan, Tom S. [Centre Hospitalier de l'Universite de Montreal, 264 Rene Levesque E, Montreal, Quebec, H2X 1P1 (Canada)], E-mail: chatsy@gmail.com; Wilson, John X. [Department of Exercise and Nutritional Sciences, University at Buffalo, Buffalo, New York, 14214 (United States); Selliah, Subajini; Bilodeau, Marc; Zwingmann, Claudia [Centre Hospitalier de l'Universite de Montreal, 264 Rene Levesque E, Montreal, Quebec, H2X 1P1 (Canada); Poon, Raymond [Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, K1A 0K9 (Canada); O'Brien, Peter J. [Faculty of Pharmacy, University of Toronto, Toronto, Ontario, M5S 3M2 (Canada)

2008-11-01

216

Determination of peptides and amino acids from wool and beer with sensitive fluorescent reagent 2-(9-carbazole)-ethyl chloroformate by reverse phase high-performance liquid chromotography and liquid chromotography mass spectrometry.  

PubMed

A new method for the sensitive determination of amino acids and peptides using the tagging reagent 2-(9-carbazole)-ethyl chloroformate (CEOC) with fluorescence (FL) detection has been developed. Identification of derivatives was carried out by liquid chromotography mass spectrometry. The chromophore in the 2-(9-fluorenyl)-ethyl chloroformate (FMOC) reagent was replaced by carbazole, which resulted in a sensitive fluorescence lerivatizing agent CEOC. CEOC can easily and quickly label peptides and amino acids. Derivatives are stable enough to be efficiently analyzed by high-performance liquid chromatography. Studies on derivatization demonstrate excellent derivative yields over the pH range 8.8-10.0. Maximal yields close to 100% are observed with three- to fourfold molar reagent excess. Derivatives exhibit strong fluorescence and allow direct injection of the reaction mixture with no significant disturbance from the major fluorescent reagent degradation by-products, such as 2-(9-carbazole)-ethanol and bis-(2-(9-carbazole)-ethyl) carbonate. In addition, the detection responses for CEOC derivatives are compared to those obtained with FMOC. The ratios AC(CEOC)/AC(FMOC) = 1.00-1.82 for fluorescence (FL) response and AC'(CEOC)/AC'(FMOC) = 1.00-1.21 for ultraviolet (UV) response are observed (here, AC and AC' are, respectively, FL and UV response). Separation of the derivatized peptides and amino acids has been optimized on a Hypersil BDS C18 column. Excellent linear responses are observed. This method was used successfully to analyze protein hydrolysates from wool and from direct-derivatized beer. PMID:12576053

You, Jinmao; Shan, Yichu; Zhen, Liang; Zhang, Lin; Zhang, Yukui

2003-02-01

217

Species differences in the formation of vabicaserin carbamoyl glucuronide.  

PubMed

Vabicaserin is a potent 5-hydroxtryptamine 2C full agonist with therapeutic potential for a wide array of psychiatric disorders. Metabolite profiles indicated that vabicaserin was extensively metabolized via carbamoyl glucuronidation after oral administration in humans. In the present study, the differences in the extent of vabicaserin carbamoyl glucuronide (CG) formation in humans and in animals used for safety assessment were investigated. After oral dosing, the systemic exposure ratios of CG to vabicaserin were approximately 12 and up to 29 in monkeys and humans, respectively, and the ratios of CG to vabicaserin were approximately 1.5 and 1.7 in mice and dogs, respectively. These differences in systemic levels of CG are likely related to species differences in the rate and extent of CG formation and elimination. Whereas CG was the predominant circulating metabolite in humans and a major metabolite in mice, dogs, and monkeys, it was a relatively minor metabolite in rats, in which oxidative metabolism was the major metabolic pathway. Although the CG was not detected in plasma or urine of rats, approximately 5% of the dose was excreted in bile as CG in the 24-h collection postdose, indicating the rat had the metabolic capability of producing the CG. In vitro, in a CO(2)-enriched environment, the CG was the predominant metabolite in dog and human liver microsomes, a major metabolite in monkey and mice, and only a very minor metabolite in rats. Carbamoyl glucuronidation and hydroxylation had similar contributions to vabicaserin metabolism in mouse and monkey liver microsomes. However, only trace amounts of CG were formed in rat liver microsomes, and other metabolites were more prominent than the CG. In conclusion, significant differences in the extent of formation of the CG were observed among the various species examined. The exposure ratios of CG to vabicaserin were highest in humans, followed by monkeys, then mice and dogs, and lowest in rats, and the in vitro metabolite profiles generally correlated well with the in vivo metabolites. PMID:20032194

Tong, Zeen; Chandrasekaran, Appavu; DeMaio, William; Jordan, Ronald; Li, Hongshan; Moore, Robin; Poola, Nagaraju; Burghart, Peter; Hultin, Theresa; Scatina, JoAnn

2009-12-23

218

Hydroxycinnamic acid ethyl esters as precursors to ethylphenols in wine.  

PubMed

A method for determining ethyl coumarate and ethyl ferulate in wine using GC-MS with deuterium-labeled analogues has been developed and used to measure the evolution of these two esters during the production of two commercial monovarietal red wines, cv. Grenache and Shiraz. During fermentation, the concentration of ethyl coumarate rose from low levels to 0.4 mg/L in Grenache and 1.6 mg/L in Shiraz wines. These concentrations then increased further during barrel aging to 1.4 and 3.6 mg/L, respectively. The concentration of ethyl ferulate was much lower, reaching a maximum of only 0.09 mg/L. Conversion of ethyl coumarate and ethyl ferulate to their corresponding ethylphenols was observed during fermentations of a synthetic medium with two strains of Dekkera bruxellensis (AWRI 1499 and AWRI 1608), while a third (strain AWRI 1613) produced no ethylphenols at all from these precursors. Strains AWRI 1499 and 1608 produced 4-ethylphenol from ethyl coumarate in 68% and 57% yields, respectively. The corresponding yields of 4-ethylguaiacol from ethyl ferulate were much lower, 7% and 3%. Monitoring of ethyl coumarate and ethyl ferulate concentration during the Dekkera fermentations showed that the selectivity for ethylphenol production according to yeast strain and the precursor was principally a result of variation in esterase activity. Consequently, ethyl coumarate can be considered to be a significant precursor to 4-ethylphenol in wines affected by these two strains of Brettanomyces/Dekkera yeast, while ethyl ferulate is not an important precursor to 4-ethylguaiacol. PMID:22324721

Hixson, Josh L; Sleep, Nicola R; Capone, Dimitra L; Elsey, Gordon M; Curtin, Christopher D; Sefton, Mark A; Taylor, Dennis K

2012-02-23

219

Rifampin induces alterations in mycophenolic acid glucuronidation and elimination: Implications for drug exposure in renal allograft recipients  

Microsoft Academic Search

Background: Exposure to mycophenolic acid (MPA) and its main metabolites (MPA 7-O-glucuronide [MPAG] and MPA acyl-glucuronide [AcMPAG]) is characterized by a large interindividual and intraindividual variability, resulting in part from variability in glucuronidation (via uridine diphosphate–glucuronosyltransferase isoforms) and excretion via multidrug resistance-associated protein 2 (MRP2). It can be hypothesized that drugs interfering with glucuronidation and excretion will alter (Ac)MPA(G) exposure.Methods:

Maarten Naesens; Dirk R. J. Kuypers; Frank Streit; Victor W. Armstrong; Michael Oellerich; Kristin Verbeke; Yves Vanrenterghem

2006-01-01

220

Targeted delivery of vitamin D to the colon using ?-glucuronides of vitamin D: therapeutic effects in a murine model of inflammatory bowel disease.  

PubMed

1,25-Dihydroxyvitamin D(3) [1,25(OH)(2)D] has been shown to inhibit development of dextran sodium sulfate (DSS)-induced colitis in mice but can also cause hypercalcemia. The aim of this study was to evaluate whether ?-glucuronides of vitamin D could deliver 1,25(OH)(2)D to the colon to ameliorate colitis while reducing the risk of hypercalcemia. Initial studies demonstrated that bacteria residing in the lower intestinal tract were capable of liberating 1,25(OH)(2)D from 1,25-dihydroxyvitamin D(3)-25-?-glucuronide [?-gluc-1,25(OH)(2)D]. We also determined that a much greater upregulation of the vitamin D-dependent 24-hydroxylase gene (Cyp24) was induced in the colon by treatment of mice with an oral dose of ?-gluc-1,25(OH)(2)D than 1,25(OH)(2)D, demonstrating targeted delivery of 1,25(OH)(2)D to the colon. We then tested ?-glucuronides of vitamin D in the mouse DSS colitis model in two studies. In mice receiving DSS dissolved in distilled water and treated with 1,25(OH)(2)D or ?-gluc-1,25(OH)(2)D, severity of colitis was reduced. Combination of ?-gluc-1,25(OH)(2)D with 25-hydroxyvitamin D(3)-25-?-glucuronide [?-gluc-25(OH)D] resulted in the greatest reduction of colitis lesions and symptoms in DSS-treated mice. Plasma calcium concentrations were lower in mice treated with ?-gluc-1,25(OH)(2)D alone or in combination with ?-gluc-25(OH)D than in mice treated with 1,25(OH)(2)D, which were hypercalcemic at the time of death. ?-Glucuronides of vitamin D compounds can deliver 1,25(OH)(2)D to the lower intestine and can reduce symptoms and lesions of acute colitis in this model. PMID:22114117

Goff, Jesse P; Koszewski, Nicholas J; Haynes, Joseph S; Horst, Ronald L

2011-11-23

221

EPA dashes ethyl`s hopes for MMT  

Microsoft Academic Search

Up until the Environmental Protection Agency (EPA; Washington) decided to deny Ethyl`s (Richmond, VA) petition to sell manganese-based gasoline additive MMT, many on Wall Street were bullish. Bets were that MMT sales could create an up to $200 million\\/year sales windfall for Ethyl with $60 million\\/year income, and push its near $26\\/share price up by at least 50 cts. But

Heller

1992-01-01

222

Determination of organotin compounds in biological samples using accelerated solvent extraction, sodium tetraethylborate ethylation, and multicapillary gas chromatography-flame photometric detection.  

PubMed

A method has been developed for species-selective analysis of organotin compounds in solid, biological samples. The procedure is based on accelerated solvent extraction (ASE) of analytes and includes extraction of the tin species with a methanol-water (90% methanol) solution of acetic acid/sodium acetate containing tropolone (0.03% w/ v), their ethylation with NaBEt(4), and separation and detection by GC-FPD. The analytical procedure was optimized with an unspiked sample of harbor porpoise ( Phocoena phocoena) liver. Effects of ASE operational variables (extraction temperature and pressure, solvent composition, number of static extraction steps) are discussed. Method detection limits (MDL) were in the range 6-10 ng(Sn) g(-1) dry weight and 7-17 ng(Sn) g(-1) dry weight for butyl- and phenyltin compounds, respectively. Recoveries were comparable with or better than those obtained by use of other procedures reported in the literature. The analytical procedure was validated by analysis of NIES No. 11 (fish tissue) certified reference material. PMID:14752583

Wasik, Andrzej; Ciesielski, Tomasz

2004-01-30

223

A new UPLC-MS/MS method for the determination of irinotecan and 7-ethyl-10-hydroxycamptothecin (SN-38) in mice: application to plasma and brain pharmacokinetics.  

PubMed

A sensitive and accurate liquid chromatography method with mass spectrometry detection using MRM in positive ion mode was developed and validated for the simultaneous quantification of irinotecan (CPT-11) and 7-ethyl-10-hydroxycamptothecin (SN-38) in mouse plasma and brain. Camptothecin (CPT) was used as internal standard. A single step protein precipitation was used for plasma sample preparation, and a liquid-liquid extraction was needed for brain sample preparation. The method was validated with respect to selectivity, extraction recovery, linearity, intra- and inter-day precision and accuracy, limit of quantification and stability. Limits of quantification were 5 ng/mL for CPT-11 and SN-38 in plasma samples and 1.25 ng/g in brain. Linear calibration curves were obtained over concentration ranges of 5-5000 ng/mL in plasma and 1.25-1250 ng/g in brain for CPT-11 and SN-38. The intra-day and inter-day variation (relative standard deviation, R.S.D.) found to be less than 15% for both substances in both media. Stability studies showed that plasma carboxylesterase had to be inactivated in order to prevent in vitro conversion of CPT-11 into SN-38. Zinc sulfate (1 M) was used to inactivate the enzyme before sample storage. Brain samples did not require enzyme inactivation. This method was successfully applied to perform brain and plasma pharmacokinetic studies of CPT-11 and SN-38 in mice after intraperitoneal administration. PMID:22551773

Goldwirt, Lauriane; Lemaitre, Florian; Zahr, Noel; Farinotti, Robert; Fernandez, Christine

2012-04-11

224

Determination of conformational and spectroscopic features of ethyl trans-alfa-cyano-3-indole-acrylate compound: an experimental and quantum chemical study.  

PubMed

The optimized geometrical structure, vibrational and electronic transitions, chemical shifts and non-linear optical properties of ethyl trans-alfa-cyano-3-indole-acrylate (C(14)H(12)N(2)O(2)) compound were presented in this study. The ground state geometrical structure and vibrational wavenumbers were carried out by using density functional (DFT/B3LYP) method with 6-311++G(d,p) as basis set. The vibrational spectra of title compound were recorded in solid state with FT-IR and FT-Raman in the range of 4000-400 cm(-1) and 4000-10 cm(-1), respectively. The fundamental assignments were done on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanical (SQM) method. The (1)H, (13)C and DEPT NMR spectra were recorded in DMSO solution, and gauge-invariant atomic orbitals (GIAO) method was used to predict the isotropic chemical shifts. The UV-Vis absorption spectra of the compound were recorded in the range of 200-800 nm in various solvents of different polarity (acetone, benzene, chlorobenzene, chloroform, DMSO, ethanol, methanol and toluene). Solvent effects were calculated using TD-DFT and CIS method. To investigate the non-linear optical properties, the polarizability, anisotropy of polarizability and molecular first hyperpolarizability were computed. A detailed description of spectroscopic behaviors of compound was given based on the comparison of experimental measurements and theoretical computations. PMID:23274474

Cinar, Mehmet; Karabacak, Mehmet

2012-12-05

225

Determination of conformational and spectroscopic features of ethyl trans-alfa-cyano-3-indole-acrylate compound: An experimental and quantum chemical study  

NASA Astrophysics Data System (ADS)

The optimized geometrical structure, vibrational and electronic transitions, chemical shifts and non-linear optical properties of ethyl trans-alfa-cyano-3-indole-acrylate (C14H12N2O2) compound were presented in this study. The ground state geometrical structure and vibrational wavenumbers were carried out by using density functional (DFT/B3LYP) method with 6-311++G(d,p) as basis set. The vibrational spectra of title compound were recorded in solid state with FT-IR and FT-Raman in the range of 4000-400 cm-1 and 4000-10 cm-1, respectively. The fundamental assignments were done on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanical (SQM) method. The 1H, 13C and DEPT NMR spectra were recorded in DMSO solution, and gauge-invariant atomic orbitals (GIAO) method was used to predict the isotropic chemical shifts. The UV-Vis absorption spectra of the compound were recorded in the range of 200-800 nm in various solvents of different polarity (acetone, benzene, chlorobenzene, chloroform, DMSO, ethanol, methanol and toluene). Solvent effects were calculated using TD-DFT and CIS method. To investigate the non-linear optical properties, the polarizability, anisotropy of polarizability and molecular first hyperpolarizability were computed. A detailed description of spectroscopic behaviors of compound was given based on the comparison of experimental measurements and theoretical computations.

Cinar, Mehmet; Karabacak, Mehmet

2013-03-01

226

Acyl glucuronidation of fluoroquinolone antibiotics by the UDP-glucuronosyltransferase 1A subfamily in human liver microsomes.  

PubMed

Acyl glucuronidation is an important metabolic pathway for fluoroquinolone antibiotics. However, it is unclear which human UDP-glucuronosyltransferase (UGT) enzymes are involved in the glucuronidation of the fluoroquinolones. The in vitro formation of levofloxacin (LVFX), grepafloxacin (GPFX), moxifloxacin (MFLX), and sitafloxacin (STFX) glucuronides was investigated in human liver microsomes and cDNA-expressed recombinant human UGT enzymes. The apparent Km values for human liver microsomes ranged from 1.9 to 10.0 mM, and the intrinsic clearance values (calculated as Vmax/Km) had a rank order of MFLX > GPFX > STFX > > LVFX. In a bank of human liver microsomes (n = 14), the glucuronidation activities of LVFX, MFLX, and STFX correlated highly with UGT1A1-selective beta-estradiol 3-glucuronidation activity, whereas the glucuronidation activity of GPFX correlated highly with UGT1A9-selective propofol glucuronidation activity. Among 12 recombinant UGT enzymes, UGT1A1, 1A3, 1A7, and 1A9 catalyzed the glucuronidation of these fluoroquinolones. Results of enzyme kinetics studies using the recombinant UGT enzymes indicated that UGT1A1 most efficiently glucuronidates MFLX, and UGT1A9 most efficiently glucuronidates GPFX. In addition, the glucuronidation activities of MFLX and STFX in human liver microsomes were potently inhibited by bilirubin with IC50 values of 4.9 microM and 4.7 microM, respectively; in contrast, the glucuronidation activity of GPFX was inhibited by mefenamic acid with an IC50 value of 9.8 microM. These results demonstrate that UGT1A1, 1A3, and 1A9 enzymes are involved in the glucuronidation of LVFX, GPFX, MFLX, and STFX in human liver microsomes, and that MFLX and STFX are predominantly glucuronidated by UGT1A1, whereas GPFX is mainly glucuronidated by UGT1A9. PMID:15769885

Tachibana, Masaya; Tanaka, Makoto; Masubuchi, Yasuhiro; Horie, Toshiharu

2005-03-15

227

Infrared spectroscopic studies of the conformation in ethyl ?-haloacetates in the vapor, liquid and solid phases  

Microsoft Academic Search

Infrared spectra of ethyl ?-fluoroacetate, ethyl ?-chloroacetate, ethyl ?-bromoacetate and ethyl ?-iodoacetate have been measured in the solid, liquid and vapor phases in the region 4000–200cm?1. Vibrational frequency assignment of the observed bands to the appropriate modes of vibration was made. Calculations at DFT B3LYP\\/6-311+G** level, Job: conformer distribution, using Spartan program ‘08, release 132 was made to determine which

Naserallah A. Jassem; Muhsin F. El-Bermani

2010-01-01

228

Bilirubin kinetics in intact rats and isolated perfused liver. Evidence for hepatic deconjugation of bilirubin glucuronides.  

PubMed Central

Most previous compartmental models describing bilirubin transport and metabolism in the liver have been validated solely by analysis of the plasma disappearance of radiolabeled bilirubin in human subjects. We now have determined the transport kinetics of a bilirubin tracer pulse by analysis of plasma, liver, and bile radioactivity data from 30 intact rats. Plasma [3H]bilirubin disappearance was best described by the sum of three exponentials, and a six-compartment model, derived by simulation analysis, was necessary and adequate to describe all experimental data. Examination of the injected radiolabeled bilirubin by extraction with hexadecyltrimethylammonium bromide and thin-layer chromatography revealed that 6.6% (mean) of the original pigment had been degraded to labeled nonbilirubin derivatives during preparation of the tracer dose. This material exhibited a significantly longer half-life (mean 50.6 min) of the plasma terminal exponential than that of authentic radiobilirubin (20.6 min). In isolated perfused rat liver, the kinetics of [3H]bilirubin in perfusate and bile readily fitted the proposed model. Compatibility of the model with the data obtained, both in the isolated liver and in vivo, required that a fraction of bilirubin conjugated in the liver be deconjugated and returned to the plasma. Deconjugation of bilirubin glucuronides was evaluated directly by infusion of bilirubin monoglucuronides, containing 14C in the glucuronosyl group, into rats with an external bile fistula. Since metabolic degradation of hydrolyzed 14C-labeled glucuronic acid yields 14CO2, this was measured in expired air. Whereas 86% of the administered labeled pigment was recovered in bile, 7% of the label appeared in 14CO2. These findings directly validate a portion of the proposed kinetic model and suggest that hepatic deconjugation of a small fraction of bilirubin glucuronides is a physiological event. Deconjugation may also account, at least in part, for the presence of increased concentrations of unconjugated bilirubin in the plasma of patients with cholestasis.

Gollan, J; Hammaker, L; Licko, V; Schmid, R

1981-01-01

229

Enzymatic synthesis of uracil glucuronide, labeling with 125/131I, and in vitro evaluation on adenocarcinoma cells.  

PubMed

Human UDP-glucuronosyltransferases (UGTs) are a family of membrane-bound enzymes of the endoplasmic reticulum. They catalyze the glucuronidation of various endogenous and exogenous compounds, converting them into more polar glucuronides. In this study, uracil glucuronide was enzymatically synthesized using a UGT-rich microsome preparate, which was separated from Hutu-80 cells. Two different glucuronide derivatives were obtained, with a total reaction yield of 22.95% +/- 2.4% (n = 4). The glucuronide ligands were defined as uracil-n-glucuronide (UNG) and uracil-o-glucuronide (UOG). These were then analyzed by high-performance liquid chromatography-mass spectrometry and labeled with I-125 and I-131, separately. The radiolabeled (125/131)I-UNG and (125/131)I-UOG presented good incorporation ratios for Hutu-80, Caco-2, Detroit 562, and ACBRI 519 cells. The incorporation ratios of (125/131)I-UOG were higher than those of (125/131)I-UNG and of other labeled components for all cell types, and were also statistically significant compared to the values of (125/131)I-UNG for primary human intestinal epithelial cells (ACBRI 519) and human intestinal adenocarcinoma cells. Cell incorporation rates of n-glucuronides and o-glucuronides were higher compared to uracil, with o-glucuronides being more selective. The results suggest that both I-125- and I-131-labeled glucuronides can be used in imaging and therapy, and further research should be done in preclinical stages. PMID:20578839

Medine, Ilker Emin; Unak, Perihan; Sakarya, Serhan; Toksöz, Feriha

2010-06-01

230

Inhibition of morphine glucuronidation in the liver microsomes of rats and humans by monoterpenoid alcohols.  

PubMed

Morphine is an important drug used to alleviate moderate to severe pain. This opiate is mainly metabolized by glucuronidation to a non-analgesic metabolite, morphine-3-glucuronide (M-3-G) and an active metabolite morphine-6-glucuronide (M-6-G). To understand the modulation of morphine glucuronidation activity by environmental factors, the effect of endogenous and food-derived compounds on morphine uridine 5'-diphosphate (UDP)-glucuronosyltransferase (UGT) in rat and human microsomes was evaluated examining the 50% inhibitory concentration (IC(50)). The liver microsomes from Sprague-Dawley rats (RLM) and humans (HLM, 150 donors, pooled microsomes) were used as enzyme sources. Of 27 compounds tested, monoterpenoid alcohols, such as borneol and iso-borneol, exhibited a strong inhibitory effect on morphine glucuronidation in rat liver microsomes (RLM), whereas we failed to detect any inhibitory effect of endogenous substances including amino acids and sugars. The substances which have the ability to inhibit the activity in RLM are also inhibitory toward morphine glucuronidation in HLM and UGT2B7 baculosomes. However, the difference was that while the strongest inhibitory effect was observed for iso-menthol in HLM, borneol was the strongest inhibitor of the activity mediated by RLM. Although zidovudine is a typical substrate of UGT2B7, the inhibition of morphine glucuronidation by zidovudine was far weaker than that of monoterpenoid alcohols. These results demonstrate that dietary and supplementary monoterpenoid alcohols modify the pharmacokinetics and pharmacodynamics of morphine through inhibition of UGT2B7. PMID:22878261

Ishii, Yuji; Iida, Naoko; Miyauchi, Yuu; Mackenzie, Peter I; Yamada, Hideyuki

2012-08-08

231

Detection and identification of 2-nitro-morphine and 2-nitro-morphine-6-glucuronide in nitrite adulterated urine specimens containing morphine and its glucuronides.  

PubMed

In vitro urine adulteration is a well-documented practice adopted by individuals aiming to evade detection of drug use, when required to undergo mandatory sports and workplace drug testing. Potassium nitrite is an effective urine adulterant due to its oxidizing potential, and has been shown to mask the presence of many drugs of abuse. However, limited research has been conducted to understand its mechanism of action, and to explore the possibility of the drugs undergoing direct oxidation to form stable reaction products. In this study, opiates including morphine, codeine, morphine-3-glucuronide and morphine-6-glucuronide were exposed to potassium nitrite in water and urine to mimic the process of nitrite adulteration. It was found that two stable reaction products were detected by liquid chromatography-mass spectrometry (LC-MS) when morphine and morphine-6-glucuronide were exposed to nitrite. Isolation and elucidation using spectrometric and spectroscopic techniques revealed that they were 2-nitro-morphine and 2-nitro-morphine-6-glucuronide, respectively. These reaction products were also formed when an authentic morphine-positive urine specimen was fortified with nitrite. 2-Nitro-morphine was found to be stable enough to undergo the enzymatic hydrolysis procedure and also detectable by gas chromatography-mass spectrometry (GC-MS) after forming a trimethylsilyl derivative. On the contrary, morphine-3-glucuronide did not appear to be chemically manipulated when exposed to potassium nitrite in urine. These reaction products are not endogenously produced, are relatively stable and can be monitored with both LC-MS and GC-MS confirmatory techniques. As a result, these findings have revealed the possibility for the use of 2-nitro-morphine and 2-nitro-morphine-6-glucuronide as markers for the indirect monitoring of morphine and morphine-6-glucuronide in urine specimens adulterated with nitrite. Copyright © 2013 John Wiley & Sons, Ltd. PMID:23592389

Luong, Susan; Fu, Shanlin

2013-04-17

232

Development and validation of screening and confirmatory methods for the detection of chloramphenicol and chloramphenicol glucuronide using SPR biosensor and liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

Biacore Q biosensor and liquid chromatography–tandem mass spectrometry (LC–MS\\/MS) based methods for the screening and confirmation of trace levels of chloramphenicol (CAP) and the mammalian metabolite chloramphenicol glucuronide (CAP-Glu) is reported. Both methods employ solvent extraction and clean-up by solid phase extraction (SPE) prior to analysis. The biosensor screening method utilises surface plasmon resonance (SPR) to determine chloramphenicol concentration in

H. M. Ashwin; S. L. Stead; J. C. Taylor; J. R. Startin; S. F. Richmond; V. Homer; T. Bigwood; M. Sharman

2005-01-01

233

Sensitive high-performance liquid chromatography–tandem mass spectrometry method for quantitative analysis of mycophenolic acid and its glucuronide metabolites in human plasma and urine  

Microsoft Academic Search

A method to determine total and free mycophenolic acid (MPA) and its metabolites, the phenolic (MPAG) and acyl (AcMPAG) glucuronides, using HPLC and mass spectrometry was developed. Mean recoveries in plasma and urine samples were >85%, and the lower limits of quantification for MPA, MPAG and AcMPAG were 0.05, 0.05 and 0.01mg\\/L, respectively. For plasma, the assay was linear over

Marie-Odile Benoit-Biancamano; Patrick Caron; Éric Lévesque; Robert Delage; Félix Couture; Chantal Guillemette

2007-01-01

234

Ethyl fuel from nonpetroleum sources  

Microsoft Academic Search

It has been shown that ethanol-ester mixtures - Ethyl Fuel - can be prepared from nonpetroleum sources such as coal, oil shale, etc. Production consists of the following steps: gasification of basic feedstock, synthesis of methanol and carbonylation of methanol to Ethyl Fuel. Depending on the final composition, preparation from methanol can be carried out with 92 + % selectivity.

H. Beuther; T. P. Kobylinski; G. M. Singerman; W. R. Pretzer

1980-01-01

235

Investigation of Therapeutic Efficiency of Bleomycin and Bleomycin-Glucuronide Labeled with (131)I on the Cancer Cell Lines.  

PubMed

Abstract The aim of this study is to determine the incorporations of radiolabeled bleomycin ((131)I-BLM) and bleomycin-glucuronide ((131)I-BLMGLU) on PC-3 (human prostate carcinoma cell line), Caco-2 (human colon adenocarcinoma cell line), Hutu-80 (Human Duodenum adenocarcinoma cell line), and A549 (Human lung adenocarcinoma epithelial cell line) cancerous cell lines. For this purpose, BLM and BLMGLU enyzmatically synthesized were labeled with (131)I, quality control studies were done and the incorporation yields of (131)I-BLM and (131)I-BLMGLU on these cell lines were measured. Quality-control studies showed that the radiolabeling yields were obtained as 95% and 90% for (131)I-BLM and (131)I-BLMGLU, respectively. Also, as a result of the cell culture studies, it was found that (131)I-BLM and (131)I-BLMGLU had higher incorporation on PC-3 cells than that of other cell lines. In addition to this, it was reported that the incorporation yield of (131)I-BLMGLU was higher than that (131)I-BLM. At the end of the study, cytotoxicities of BLM and BLMGLU on PC-3 cancerous cell line were inspected and fluorescent images of BLM and BLMGLU were taken on PC-3 cells by using fluorescein isothiocyanate. In conclusion, cell culture studies demonstrated that the incorporation values of (131)I-BLMGLU on the four cell lines were about five to six times higher than (131)I-BLM. Radiolabeled glucuronide derivatives can be used in cancer therapy and tumor imaging, depending on the properties of radioiodine for the ?-glucuronidase-rich tissues because glucuronidation leads to rapid and higher incorporation on adenocarcinoma cells. PMID:23350895

Ediz, Melis; Avc?ba??, U?ur; Unak, Perihan; Müftüler, Fazilet Zümrüt Biber; Medine, Emin ?lker; Yurt K?lçar, Ayfer; Demiro?lu, Hasan; Gümü?er, Fikriye Gül; Sakarya, Serhan

2013-01-25

236

Correlation between plasma concentration ratios of SN-38 glucuronide and SN-38 and neutropenia induction in patients with colorectal cancer and wild-type UGT1A1 gene  

PubMed Central

In irinotecan (CPT-11)-based chemotherapy, neutropenia and diarrhea are often induced. In the present study, the clinical significance of the concentration ratios of 7-ethyl-10-hydroxycamptothecin (SN-38) glucuronide (SN-38G) and SN-38 in the plasma in predicting CPT-11-induced neutropenia was examined. A total of 17 patients with colorectal cancer and wild-type UDP-glucuronosyltransferase (UGT)1A1 gene were enrolled and treated with CPT-11 as part of the FOLFIRI regimen [CPT-11 and fluorouracil (5-FU)]. Blood was taken exactly 15 min following a 2-h continuous infusion of CPT-11. Plasma concentrations of SN-38, SN-38G and CPT-11 were determined by a modified high-performance liquid chromatography (HPLC) method. The median, maximum and minimum values of plasma SN-38G/SN-38 ratios were 4.25, 7.09 and 1.03, respectively, indicating that UGT activities are variable among patients with the wild-type UGT1A1 gene. The plasma SN-38G/SN-38 ratios decreased with an increase in the trial numbers of chemotherapy (r=0.741, p=0.000669), suggesting that CPT-11 treatment suppresses UGT activity, and the low plasma SN-38G/SN-38 ratios resulted in the induction of greater neutropenia. However, in this analysis, 2 clearly separated regression lines were observed between plasma SN-38G/SN-38 ratios and neutropenia induction. In conclusion, UGT activity involved in SN-38 metabolism is variable among patients with the wild-type UGT1A1 gene, and each CPT-11 treatment suppresses UGT activity. One-point determination of the plasma SN-38G/SN-38 ratio may provide indications for the prediction of CPT-11-induced neutropenia and adjustment of the optimal dose, although further studies are required.

HIROSE, KOICHI; KOZU, CHIHIRO; YAMASHITA, KOSHIRO; MARUO, EIJI; KITAMURA, MIZUHO; HASEGAWA, JUNICHI; OMODA, KEI; MURAKAMI, TERUO; MAEDA, YORINOBU

2011-01-01

237

49 CFR 173.322 - Ethyl chloride.  

Code of Federal Regulations, 2011 CFR

... 2011-10-01 2011-10-01 false Ethyl chloride. 173.322 Section 173.322 Transportation...Preparation and Packaging § 173.322 Ethyl chloride. Ethyl chloride must be packaged in any of the following...

2011-10-01

238

Anti-tumour activity and toxicity of the new prodrug9-aminocamptothecin glucuronide (9ACG) in mice  

PubMed Central

Cancer chemotherapy is limited by the modest therapeutic index of most antineoplastic drugs. Some glucuronide prodrugs may display selective anti-tumour activity against tumours that accumulate ?-glucuronidase. We examined the toxicity and anti-tumour activity of 9-aminocamptothecin glucuronide, a new glucuronide prodrug of 9-aminocamptothecin, to evaluate its potential clinical utility. 9-aminocamptothecin glucuronide was 25–60 times less toxic than 9-aminocamptothecin to five human cancer cell lines. ?-glucuronidase activated 9-aminocamptothecin glucuronide to produce similar cell killing as 9-aminocamptothecin or topotecan. The in vivo toxicity of 9-aminocamptothecin glucuronide in BALB/c mice was dose-, route-, sex- and age-dependent. 9-aminocamptothecin glucuronide was significantly less toxic to female than to male mice but the difference decreased with age. 9-aminocamptothecin glucuronide and 9-aminocamptothecin produced similar inhibition (?80%) of LS174T human colorectal carcinoma tumours. 9-aminocamptothecin glucuronide cured a high percentage of CL1-5 human lung cancer xenografts with efficacy that was similar to or greater than 9-aminocamptothecin, irinotecan and topotecan. The potent anti-tumour activity of 9-aminocamptothecin glucuronide suggests that this prodrug should be further evaluated for cancer treatment. British Journal of Cancer (2002) 86, 1634–1638. DOI: 10.1038/sj/bjc/6600317 www.bjcancer.com © 2002 Cancer Research UK

Prijovich, Z M; Chen, B-M; Leu, Y-L; Chern, J-W; Roffler, S R

2002-01-01

239

A study of ethyl glucuronide in post-mortem blood as a marker of ante-mortem ingestion of alcohol  

Microsoft Academic Search

The possibility of post-mortem production of ethanol makes correct interpretation of ethanol detection in forensic autopsy samples difficult. Even though the levels of ethanol formed post-mortem are generally low, this may be highly relevant in cases where intake of alcohol was forbidden, for instance for pilots, professional drivers and countries with low legal alcohol limits for driving. Different criteria are

Gudrun Høiseth; Ritva Karinen; Asbjørg S. Christophersen; Linda Olsen; Per Trygve Normann; Jørg Mørland

2007-01-01

240

In Vitro Glucuronidation of the Antibacterial Triclocarban and Its Oxidative MetabolitesS?  

PubMed Central

Triclocarban (3,4,4?-trichlorocarbanilide; TCC) is widely used as an antibacterial in bar soaps. During use of these soaps, a significant portion of TCC is absorbed by humans. For the elimination from the body, glucuronidation plays a key role in both biliary and renal clearance. To investigate this metabolic pathway, we performed microsomal incubations of TCC and its hydroxylated metabolites 2?-OH-TCC, 3?-OH-TCC, and 6-OH-TCC. Using a new liquid chromatography-UV-mass spectrometry method, we could show a rapid glucuronidation for all OH-TCCs by the uridine-5?-diphosphate-glucuronosyltransferases (UGT) present in liver microsomes of humans (HLM), cynomolgus monkeys (CLM), rats (RLM), and mice (MLM). Among the tested human UGT isoforms, UGT1A7, UGT1A8, and UGT1A9 showed the highest activity for the conjugation of hydroxylated TCC metabolites followed by UGT1A1, UGT1A3, and UGT1A10. Due to this broad pattern of active UGTs, OH-TCCs can be efficiently glucuronidated in various tissues, as shown for microsomes from human kidney (HKM) and intestine (HIM). The major renal metabolites in humans, TCC-N-glucuronide and TCC-N?-glucuronide, were formed at very low conversion rates (<1%) by microsomal incubations. Low amounts of N-glucuronides were generated by HLM, HIM, and HKM, as well as by MLM and CLM, but not by RLM, according to the observed species specificity of this metabolic pathway. Among the human UGT isoforms, only UGT1A9 had activity for the N-glucuronidation of TCC. These results present an anomaly where in vivo the predominant urinary metabolites of TCC are N and N?-glucuronides, but these compounds are slowly produced in vitro.

Schebb, N. H.; Franze, B.; Maul, R.; Ranganathan, A.

2012-01-01

241

Profiling of 19-norandrosterone sulfate and glucuronide in human urine: Implications in athlete's drug testing  

Microsoft Academic Search

19-Norandrosterone (19-NA) as its glucuronide derivative is the target metabolite in anti-doping testing to reveal an abuse of nandrolone or nandrolone prohormone. To provide further evidence of a doping with these steroids, the sulfoconjugate form of 19-norandrosterone in human urine might be monitored as well. In the present study, the profiling of sulfate and glucuronide derivatives of 19-norandrosterone together with

Emmanuel Strahm; Norbert Baume; Patrice Mangin; Martial Saugy; Christiane Ayotte; Christophe Saudan

2009-01-01

242

The ABC-like vacuolar transporter for rye mesophyll flavone glucuronides is not species-specific.  

PubMed

In many cases, the vacuolar uptake of secondary metabolites has been demonstrated to be strictly specific for a given compound and plant species. While most plants contain glycosylated secondary substances, few cases are known where flavonoids may also carry negative charges, e.g. as glucuronide conjugates. Vacuolar transport of glucosylated phenylpropanoid derivatives has been shown to occur by proton substrate antiport mechanisms (Klein, M., Weissenböck. G., Dufaud, A., Gaillard, C., Kreuz, K., Martinoia, E., 1996. Different energization mechanisms drive the vacuolar uptake of a flavonoid glucoside and a herbicide glucoside. J. Biol. Chem. 271, 29,666-29,671). In contrast, flavone glucuronides appearing specifically in rye mesophyll vacuoles are taken up by direct energisation utilising MgATP, strongly arguing for the presence of an ATP-binding cassette (ABC) transporter belonging to the subfamily of multidrug resistance-associated proteins (MRP) on the rye vacuolar membrane (Klein, M., Martinoia, E., Hoffmann-Thoma, G., Weissenböck, G., 2000. A membrane-potential dependent, ubiquitous ABC-like transporter mediates the vacuolar uptake of rye flavone glucuronides regulation of glucturonide uptake by glutathione and its conjugates. Plant Journal 21, 289-304). MRPs are known to transport negatively charged organic anions. Results presented here suggest that the vacuolar directly energised MRP-like glucuronate pump for plant-specific flavone glucuronides is ubiquitously present in diverse plant species since rye flavone glucuronides are taken up into vacuoles isolated from the barley mesophyll or from the broccoli stalk parenchyma representing two species which do not synthesise glucuronidated secondary compounds. According to the transport characteristics and inhibition profile observed we propose the existence of a high-capacity, uncoupler-insensitive vacuolar ABC transporter for flavone glucuronides and possibly other negatively charged organic compounds -- plant-born or xenobiotic -- irrespective of the plant's capability to endogenously produce glucuronidated compounds. PMID:11219807

Klein, M; Martinoia, E; Hoffmann-Thoma, G; Weissenböck, G

2001-01-01

243

cis- and trans-Resveratrol Are Glucuronidated in Rat Brain, Olfactory Mucosa and Cultured Astrocytes  

Microsoft Academic Search

Background\\/Aims: Glucuronidation of cis- and trans-resveratrol (3,5,4’-trihydroxy-trans-stilbene), which is a naturally occurring phytoalexin known to exert a number of beneficial health effects, was investigated in rat brain, cultured astrocytes and olfactory mucosa. Methods: The isomers were incubated with tissue homogenates, microsomes, or rat liver recombinant UDP-glucuronosyltransferases in the presence of UDP-glucuronic acid. The glucuronides were separated by HPLC and quantitated.

Nicole Sabolovic; Tony Heurtaux; Anne-Claude Humbert; Stéphanie Krisa; Jacques Magdalou

2007-01-01

244

Characterization of In Vitro Glucuronidation Clearance of a Range of Drugs in Human Kidney Microsomes: Comparison with Liver and Intestinal Glucuronidation and Impact of Albumin  

PubMed Central

Previous studies have shown the importance of the addition of albumin for characterization of hepatic glucuronidation in vitro; however, no reports exist on the effects of albumin on renal or intestinal microsomal glucuronidation assays. This study characterized glucuronidation clearance (CLint, UGT) in human kidney, liver, and intestinal microsomes in the presence and absence of bovine serum albumin (BSA) for seven drugs with differential UDP-glucuronosyltransferase (UGT) 1A9 and UGT2B7 specificity, namely, diclofenac, ezetimibe, gemfibrozil, mycophenolic acid, naloxone, propofol, and telmisartan. The impact of renal CLint, UGT on accuracy of in vitro-in vivo extrapolation (IVIVE) of glucuronidation clearance was investigated. Inclusion of 1% BSA for acidic drugs and 2% for bases/neutral drugs in incubations was found to be suitable for characterization of CLint, UGT in different tissues. Although BSA increased CLint, UGT in all tissues, the extent was tissue- and drug-dependent. Scaled CLint, UGT in the presence of BSA ranged from 2.22 to 207, 0.439 to 24.4, and 0.292 to 23.8 ml · min?1 · g tissue?1 in liver, kidney, and intestinal microsomes. Renal CLint, UGT (per gram of tissue) was up to 2-fold higher in comparison with that for liver for UGT1A9 substrates; in contrast, CLint, UGT for UGT2B7 substrates represented approximately one-third of hepatic estimates. Scaled renal CLint, UGT (in the presence of BSA) was up to 30-fold higher than intestinal glucuronidation for the drugs investigated. Use of in vitro data obtained in the presence of BSA and inclusion of renal clearance improved the IVIVE of glucuronidation clearance, with 50% of drugs predicted within 2-fold of observed values. Characterization and consideration of kidney CLint, UGT is particularly important for UGT1A9 substrates.

Gill, Katherine L.; Houston, J. Brian

2012-01-01

245

Evidence for P-glycoprotein-modulated penetration of morphine-6-glucuronide into brain capillary endothelium.  

PubMed Central

1. Morphine-6-glucuronide is one of the major metabolites of morphine. The potent analgesic action of this compound together with its potential lower apparent toxicity in man, when compared with morphine, indicated its clinical importance. 2. Primary cultures of porcine brain capillary endothelial cells were used to study brain penetration of morphine-6-glucuronide. Biochemical characterization of the cell cultures revealed a marked enrichment in enzymatic activity of alkaline phosphatase (56 fold) and angiotensin converting enzyme (230 fold) as compared to whole brain tissue. By immunostaining the presence of vimentin, factor VIII, the tight junction associated protein ZO-1, and P-glycoprotein was shown. Functional characterization revealed that the carrier system responsible for transport of neutral amino acids was intact. 3. Uptake and transport of morphine-6-glucuronide was marginal and in the range of the extracellular marker sucrose. However, uptake of morphine-6-glucuronide was enhanced significantly (P < 0.0001) in presence of the inhibitors of P-glycoprotein, verapamil or vincristine. The finding that morphine-6-glucuronide may serve as a substrate for P-glycoprotein was confirmed in multidrug-resistant P388 tumour cells. 4. We conclude that penetration of the blood-brain barrier by morphine-6-glucuronide may depend on the expression of the product of the multidrug-resistance (MDR) gene in brain capillary endothelial cells. Images Figure 1 Figure 2 Figure 4 Figure 5

Huwyler, J.; Drewe, J.; Klusemann, C.; Fricker, G.

1996-01-01

246

Simple measurement of gluconeogenesis by direct 2H NMR analysis of menthol glucuronide enrichment from 2H2O.  

PubMed

The contribution of gluconeogenesis to fasting glucose production was determined by a simple measurement of urinary menthol glucuronide (MG) 2H enrichment from 2H2O. Following ingestion of 2H2O (0.5% body water) during an overnight fast and a pharmacological dose (400 mg) of a commercial peppermint oil preparation the next morning, 364 micromol MG was quantitatively recovered from a 2-h urine collection by ether extraction and a 125 micromol portion was directly analyzed by 2H NMR. The glucuronide 2H-signals were fully resolved and their relative intensities matched those of the monoacetone glucose derivative. The pharmacokinetics and yields of urinary MG after ingestion of 400 mg peppermint oil as either gelatin or enteric-coated capsules 1 h before breakfast were quantified in five healthy subjects. Gelatin capsules yielded 197 +/- 81 micromol of MG from the initial 2-h urine collection while enteric-coated capsules gave 238 +/- 84 micromol MG from the 2- to 4-h urine collection. PMID:16032678

Ribeiro, Angela; Caldeira, M Madalena; Carvalheiro, Manuela; Bastos, Margarida; Baptista, Carla; Fagulha, Ana; Barros, Luisa; Barosa, Cristina; Jones, John G

2005-08-01

247

Nitrosation Reactions of Ethyl Centralite.  

National Technical Information Service (NTIS)

Preliminary experiments are described in which ethyl centralite, a stabilizer frequently used in double-base propellants, was reacted with nitrous acid in various concentrations. The chemical reactions taking place led to the formation of numerous derivat...

B. T. Newbold K. Taymaz R. MacDonald

1977-01-01

248

Molecular Structure of Ethyl maltol  

NSDL National Science Digital Library

Ethyl maltol was discovered in the 1970s. It was originally isolated from larch tree bark and is produced through fermentation-organic synthesis. Ethyl maltol occurs naturally in cereal, bread crust, coffee, and cocoa. This substance is also used as a flavor enhancer because it tends to mask bad tasting chemicals, and heightens richness and creaminess. The compound has been employed as a flavor enhancer in wine, chocolate, vanilla, fruit flavored drinks, pastries, candy, tobacco, cosmetics, and medicines.

2002-10-11

249

Sensitive determination method for mercury ion, methyl-, ethyl-, and phenyl-mercury in water and biological samples using high-performance liquid chromatography with chemiluminescence detection.  

PubMed

A sensitive determination method for mercury speciation analysis was developed. Four mercury species, mercury ion, methylmercury, ethylmercury, and phenylmercury, were complexed with emetine-dithiocarbamate (emetine-CS(2)), and then injected onto a HPLC instrument coupled with a tris(2,2'-bipyridine)ruthenium(III) chemiluminescence detection system. The emetine-CS(2) complexing agent was effectively used to measure the concentration in addition to serving as a separation and detection reagent. The calibration curves for these mercury complexes were linear in the range of 0.050 - 10 ?g L(-1) (as Hg). The limit of detection for (emetine-CS(2))(2)Hg, emetine-CS(2)-methylmercury, emetine-CS(2)-ethylmercury, and emetine-CS(2)-phenylmercury were 30, 17, 21, and 22 ng L(-1), respectively. The sensitivity of this method enables the determination of mercury species in water samples at sub-ppb levels. Furthermore, the method was applied to biological samples in combination with acid leaching and liquid-liquid extraction using emetine-CS(2) as an extraction reagent. The determination results were in good agreement with the values of the certified reference materials. PMID:23059991

Kodamatani, Hitoshi; Matsuyama, Akito; Saito, Keiitsu; Kono, Yuriko; Kanzaki, Ryo; Tomiyasu, Takashi

2012-01-01

250

Familial resemblance for free androgens and androgen glucuronides in sedentary black and white individuals: the HERITAGE Family Study  

Microsoft Academic Search

Familial correlation analyses were used to evaluate the familial aggregation of plasma androgens and androgen glucuronides (testosterone (TESTO), dihydrotestos- terone (DHT), androstane-3,17-diol glucuronide (3-DIOL-G), and androsterone glucuronide (ADT-G)) in 505 members of 99 white families and 296 members of 111 black families participating in the Health, Risk Factors, Exercise Training and Genetics (HERITAGE) Family Study. Each of these four measures

Y Hong; J Gagnon; T Rice; L Pérusse; A S Leon; J S Skinner; J H Wilmore; D C Rao

2001-01-01

251

Radioiodination and preliminary biological tests of aniline-mustard and its glucuronide conjugate as a potential anticancer prodrug  

Microsoft Academic Search

Aniline-mustard and its glucuronide conjugate were radioiodinated with 131I. The preliminary dynamic tests were carried out on rabbits. The scintigrams showed clearly that the glucuronide conjugate of aniline-mustard was very quickly cleared from the metabolism, accumulating in the bladder in about 15 minutes. The clearance time of radioiodinated aniline-mustard-glucuronide was considerably longer (about 45 min.). The results obtained from the

T. Ünak; Z. Akgün; Y. Duman; Y. Yildirim; U. Avciba?i; B. Çetinkaya

2003-01-01

252

Creatine ethyl ester: a new substrate for creatine kinase.  

PubMed

The creatine kinase/phosphocreatine system plays a key role in cell energy buffering and transport, particularly in cells with high or fluctuating energy requirements, like neurons, i.e. it participates in the energetic metabolism of the brain. Creatine depletion causes several nervous system diseases, alleviated by phosphagen supplementation. Often, the supplementation contains both creatine and creatine ethyl ester, known to improve the effect of creatine through an unknown mechanism. In this work we showed that purified creatine kinase is able to phosphorilate the creatine ethyl ester. The K(m) and V(max) values, as well as temperature and pH optima were determined. Conversion of the creatine ethyl ester into its phosphorylated derivative, sheds light on the role of the creatine ethyl ester as an energy source in supplementation for selected individuals. PMID:22642114

Ravera, S; Adriano, E; Balestrino, M; Panfoli, I

253

Is the Kidney a Major Storage Site for Thyroxine as Thyroxine Glucuronide?  

PubMed Central

Background Previous studies have shown that thyroxine (T4) is stored as T4 glucuronide (T4G) in the kidney, and that 24 hours after administration of [125I]T4 to mice, 17% of the radioactivity was present in the kidneys, whereas only 4% was found in the liver. The present study was carried out to determine the relative amounts of conjugated and unconjugated T4 and 3,5,3?-triiodothyronine (T3) in the kidney and liver, and whether the conjugated hormones are extracted from tissues using our established extraction protocols, and detected in our radioimmunoassays (RIAs) for T4 and T3. Methods Mice were injected with 10??Ci [125I]T4 or [125I]T3 and 24 hours later, the labeled compounds present in serum, kidney, liver, and urine were extracted and analyzed by paper chromatography before and after treatment with ?-glucuronidase. In addition, the amounts of endogenous T4 and T3 in extracts of mouse kidney and liver were measured by RIA before and after treatment with ?-glucuronidase. Results After [125I]T4, more than 95% of the total kidney and liver radioactivity was extracted, and in the kidney, almost all of it was present in a conjugated form, mostly as T4G. The liver also contained T4G, but none was present in serum or urine. T3 glucuronide (T3G) was also found in the kidney and liver after the administration of [125I]T3. Analysis by RIA of the endogenous T4 content in extracts of kidney before and after hydrolysis by ?-glucuronidase revealed that a substantial fraction of the T4 in both tissues was present as T4G, and the T4G was not detected in the RIA. Furthermore, the combined T4+T4G content in the kidney expressed per gram of tissue was significantly higher than that in the liver or serum. In contrast, the kidney content of T3+T3G was very low compared with that of T4+T4G. Conclusions In summary, we have shown that the kidney stores a significant amount of T4 as T4G. Since T4G deconjugation can occur rapidly in the kidney, it is possible that this tissue participates in maintaining extrathyroidal serum T4 homeostasis.

Buitendijk, Maarten

2012-01-01

254

Development, validation and comparison of two microextraction techniques for the rapid and sensitive determination of pregabalin in urine and pharmaceutical formulations after ethyl chloroformate derivatization followed by gas chromatography-mass spectrometric analysis.  

PubMed

The present article reports first time the use of solid-phase microextraction (SPME) and dispersive liquid-liquid microextraction (DLLME) to extract pregabalin (PRG) from urine and pharmaceutical formulations followed by GC-MS analysis after ethyl chloroformate (ECF) derivatization. PRG is an antiepileptic and analgesic drug, which is a structural analogue of ?-amino-butyric acid (GABA). It is approved by Food and Drug Administration (FDA) for the treatment of central nervous system (CNS) disorders and neuropathic pain. Initially PRG was derivatized with ECF in the presence of pyridine at room temperature for 30s. Experimental parameters were investigated for derivatization, SPME and DLLME conditions. The limit of detection (LOD) and limit of quantitation (LOQ) were found to be 0.019 ?g/ml and 0.063 ?g/ml for SPME and 0.022 ?g/ml and 0.075 ?g/ml for DLLME respectively. The percentage recovery, in case of SPME was in the range of 83-98% while for DLLME it is in the range of 84-98%. The intra and inter-day precisions were found to be less than 6%. The developed methods after ECF derivatization were found to be simple, fast, efficient and inexpensive. DLLME has several advantages like lesser extraction time and cost effectiveness as compared to SPME. The developed methods may find wide application for the routine determination of PRG in biological as well as in quality control samples of pharmaceutical formulations. PMID:22677651

Mudiam, Mohana Krishna Reddy; Chauhan, Abhishek; Jain, Rajeev; Ch, Ratnasekhar; Fatima, Ghizal; Malhotra, Ekta; Murthy, R C

2012-05-11

255

Low Level Determinations of Methyl Methanesulfonate and Ethyl Methanesulfonate Impurities in Emtricitabine Active Pharmaceutical Ingredient by LC/MS/MS Using Electrospray Ionization  

PubMed Central

Alkyl methanesulfonates have been highlighted as potential genotoxic impurities (PGIs). A sensitive LC/MS/MS method was developed and validated for the determination of Alkyl methanesulfonate impurities in Emtricitabine API (active pharmaceutical ingredient). LC/MS/MS method on Zorbax SB C18 column (150 × 4.6 mm i.d.), 3.5 ?m, with electrospray ionization (ESI) in multiple reaction monitoring (MRM) mode was used. The proposed method was specific, linear, accurate, rugged and precise. The calibration curves showed good linearity over the concentration range of 0.0025 ?g/ml to 0.3 ?g/ml the correlation coefficient was >0.999 in each case. Method had very low limit of detection (LOD) and limit of quantification (LOQ) as 0.3 ?g/g and 0.4 ?g/g respectively for both the analytes. Accuracy was observed within 80%–120% for both the analytes. This method can be further extended a good quality control tool for low level quantitation of Alkyl methanesulfonate impurities in other API.

Kakadiya, P.R.; Chandrashekhar, T.G.; Ganguly, S.; Singh, D.K.; Singh, V.

2011-01-01

256

Synthesis, spectroscopic characterization and X-ray structure determinations and packing of tetralkylammonium trans-diamminetetranitrocobaltate(III) complex salts where alkyl=methyl or ethyl  

NASA Astrophysics Data System (ADS)

The two cobalt(III) complex salts [(CH3)4N][trans-Co(NH3)2(NO2)4] (I) and [(C2H5)4N][trans-Co(NH3)2(NO2)4] (II) have been synthesized in high yields by reacting equimolar quantities of [(CH3)4N]Br and [(C2H5)4N]Cl with K[trans-Co(NH3)2(NO2)4], respectively in aqueous medium at room temperature. The salt I crystallized with monoclinic space group P 21/m having cell dimensions a=6.1926(7), b=18.248(3), c=6.2335(6) Å, ?=90.078(7)°, V=704.41(16) Å3, Z=2, R=0.0868 and the salt II crystallized with monoclinic space group P 21/c having cell dimensions a=10.2635(18), b=9.0480(15), c=9.752(2) Å, ?=104.493(12)°, V=876.8(3) Å3, Z=2, R=0.0408. X-ray structure determination revealed the presence of discrete ions, [(CH3)4N]+ and [trans-Co(NH3)2(NO2)4]- in I and [(C2H5)4N]+ and [trans-Co(NH3)2(NO2)4]- in II. In the anion, the central metal atom cobalt(III) is octahedrally surrounded in trans geometry. The crystal lattice is stabilized by electrostatic forces of attractions and hydrogen bonding interactions in I. These are the first X-ray structures of salts containing the tetralkylammonium cations and the anion [trans-Co(NH3)2(NO2)4]-. The packing diagrams show a layered structures in the two salts.

Sharma, Raj Pal; Vermani, Bal Krishan; Sharma, Rajni; Bala, Ritu; Gill, Dip Singh; Salas, Juan M.; Quiros, Miguel

2006-02-01

257

Effect of UDP-glucuronosyltransferase 1A8 polymorphism on raloxifene glucuronidation.  

PubMed

Raloxifene is an antiestrogen marketed for the treatment of osteoporosis. The major metabolic pathway of raloxifene is glucuronidation at 6- and/or 4'-positions, which is mainly catalyzed by UDP-glucuronosyltransferase 1A8 (UGT1A8) expressed in extrahepatic tissues such as the small intestine and colon. Two non-synonymous allelic variants, termed UGT1A8*2 (518C>G, A173G) and UGT1A8*3 (830G>A, C277Y), have been found in Caucasian, African-American and Asian populations. In this study, the effect of amino acid substitutions in UGT1A8 on raloxifene glucuronidation was studied using recombinant UGT1A8 enzymes of wild-type (UGT1A8.1) and variant UGT1A8 (UGT1A8.2 and UGT1A8.3) expressed in Sf9 cells. Raloxifene 6- and 4'-glucuronidation by UGT1A8.1 exhibited negative allosteric kinetics. The Km and Vmax values of UGT1A8.1 were 15.0 ?M and 111 pmol/min/mg protein for 6-glucuronidation, and 9.35 ?M and 232 pmol/min/mg protein for 4'-glucuronidation, respectively. The kinetics of raloxifene 6-glucuronidation by UGT1A8.2 was positive allosteric, whereas the kinetics of raloxifene 4'-glucuronidation was negative allosteric. The S50 value of raloxifene 6-glucuronidation was markedly low (1.2%) compared with the Km value of UGT1A8.1, and the Km value for raloxifene 4'-glucuronidation was 29% that of UGT1A8.1. The Vmax value for raloxifene 6-glucuronidation by UGT1A8.2 was comparable to that of UGT1A8.1, whereas the Vmax value for raloxifene 4'-glucuronidation was significantly lower (54%) than that of UGT1A8.1. The activities of raloxifene 6- and 4'-glucuronidation in UGT1A8.3 were markedly lower than those of UGT1A8.1. In mycophenolic acid glucuronidation, the kinetics by wild-type and variant UGT1A8s fitted the Michaelis-Menten model. The Km and Vmax values of UGT1A8.1 were 123 ?M and 4820 pmol/min/mg protein, respectively. The Km and Vmax values of UGT1A8.2 were comparable to those of UGT1A8.1. The Km value of UGT1A8.3 was similar to that of UGT1A8.1, whereas the Vmax value was reduced to 2.4% of UGT1A8.1. These findings suggest that A173G and C277Y substitutions of UGT1A8 change the metabolic ability toward raloxifene, and that the polymorphic alleles of UGT1A8 may influence the clinical response and bioavailability of medicines metabolized mainly by UGT1A8. PMID:23499758

Kokawa, Yuki; Kishi, Naoki; Jinno, Hideto; Tanaka-Kagawa, Toshiko; Narimatsu, Shizuo; Hanioka, Nobumitsu

2013-03-14

258

Effects of herbal supplements on drug glucuronidation. Review of clinical, animal, and in vitro studies.  

PubMed

The use of herbal supplements has increased steadily over the last decade. Recent surveys show that many people who take herbal supplements also take prescription and nonprescription drugs, increasing the risk for potential herb-drug interactions. While cytochrome P450-mediated herb-drug interactions have been extensively characterized, the effects of herbal extracts and constituents on UDP-glucuronosyl transferase (UGT) enzymes have not been adequately studied. Thus, the purpose of this review is to evaluate current evidence on the glucuronidation of phytochemicals and the potential for UGT-mediated herb-drug interactions with the top-selling herbal supplements in the United States and Europe. IN VITRO and animal studies indicate that cranberry, GINKGO BILOBA, grape seed, green tea, hawthorn, milk thistle, noni, soy, St. John's wort, and valerian are rich in phytochemicals that can modulate UGT enzymes. However, the IN VIVO consequences of these interactions are not well understood. Only three clinical studies have investigated the effects of herbal supplements on drugs cleared primarily through UGT enzymes. Evidence on the potential for commonly used herbal supplements to modulate UGT-mediated drug metabolism is summarized. Moreover, the need for further research to determine the clinical consequences of the described interactions is highlighted. PMID:21049395

Mohamed, Mohamed-Eslam F; Frye, Reginald F

2010-11-03

259

Glycerolysis of acyl glucuronides as an artifact of in vitro drug metabolism incubations.  

PubMed

During an investigation of the in vitro glucuronidation of benoxaprofen by human liver S-9 fraction, an unusual drug-related entity possessing a protonated molecular ion that was 74 mass units greater than the parent drug was observed. It was identified as the glycerol ester of benoxaprofen. Formation of this entity required inclusion of uridine diphosphoglucuronic acid (UDPGA) in the incubation, suggesting the formation of benoxaprofen acyl glucuronide followed by transesterification with the glycerol present in the incubation due to its presence as a stabilizer for liver subcellular fractions. Formation occurred during the sample work-up procedure while the samples were subjected to evaporation in vacuo, which does not remove glycerol. Conversion of purified benoxaprofen acyl glucuronide to the glycerol ester was demonstrated in glycerol at 37 degrees C. Other drugs that are converted to acyl glucuronides in vitro (diclofenac, mefenamic acid, tolmetin, and naproxen) were also shown to form corresponding glycerol esters when incubated with human liver S-9 fraction and UDPGA. The potential formation of glycerol esters of carboxylic acid drugs undergoing acyl glucuronidation in vitro represents an experimental artifact to which drug metabolism scientists should be aware. PMID:19439485

Obach, R Scott

2009-05-13

260

Identification of etoposide glucuronide as a major metabolite of etoposide in the rat and rabbit.  

PubMed

Isolated livers from male Sprague-Dawley rats were perfused at 20 ml/min for 3 h at 37 degrees C with 100 ml of an oxygenated, recirculating solution of 20% rat blood in Krebs bicarbonate buffer containing 20 micrograms/ml [3H]etoposide. Ninety % of administered radioactivity was eliminated in bile over a 3-h collection period. The clearance of etoposide was 3.56 ml/min indicating that, in the rat, it is not highly extracted. Its clearance is, therefore, independent of hepatic blood flow. Etoposide was both excreted into the bile and metabolized by the liver. Perfusate and bile samples analyzed by reverse-phase high-performance liquid chromatography techniques were found to contain three peaks of radioactivity. Positive and negative ion fast atom bombardment mass spectrometry identified the first two peaks as etoposide glucuronides and the third peak as parent drug. Following the i.v. administration of etoposide to rabbits, etoposide glucuronide was also identified in rabbit urine. The recovery of etoposide both from rabbit urine and rat bile was increased by preincubation with glucuronidase. However, the glucuronides were relatively resistant to the action of glucuronidase and showed varying sensitivity to the type of glucuronidase and the reaction conditions used. These studies document the presence of etoposide glucuronide as an etoposide metabolite in two mammalian species and suggest that previous clinical studies using beta-glucuronidase to quantitate glucuronide formation may have underestimated this metabolite due to its relative resistance to some glucuronidase preparations. PMID:3349461

Hande, K; Anthony, L; Hamilton, R; Bennett, R; Sweetman, B; Branch, R

1988-04-01

261

Ethyl diazoacetate synthesis in flow  

PubMed Central

Summary Ethyl diazoacetate is a versatile compound in organic chemistry and frequently used on lab scale. Its highly explosive nature, however, severely limits its use in industrial processes. The in-line coupling of microreactor synthesis and separation technology enables the synthesis of this compound in an inherently safe manner, thereby making it available on demand in sufficient quantities. Ethyl diazoacetate was prepared in a biphasic mixture comprising an aqueous solution of glycine ethyl ester, sodium nitrite and dichloromethane. Optimization of the reaction was focused on decreasing the residence time with the smallest amount of sodium nitrite possible. With these boundary conditions, a production yield of 20 g EDA day?1 was achieved using a microreactor with an internal volume of 100 ?L. Straightforward scale-up or scale-out of microreactor technology renders this method viable for industrial application.

Delville, Marielle M E; van Hest, Jan C M

2013-01-01

262

Evaluation of bisphenol A glucuronidation according to UGT1A1*28 polymorphism by a new LC-MS/MS assay.  

PubMed

The endocrine disruptor bisphenol A (BPA) is a frequently used chemical in the manufacture of consumer products. In humans, BPA is extensively metabolized to BPA glucuronide (BPAG) by different UDP-glucuronosyltransferase (UGT) isoforms. The study has been performed with the intention to improve the accuracy of published physiologically based pharmacokinetic models and to improve regulatory risk assessments of BPA. In order to gain insight into intestine, kidney, liver, and lung glucuronidation of BPA, human microsomes of all tested organs were used. BPAG formation followed Michaelis-Menten kinetics in the intestine and kidney, but followed substrate inhibition kinetics in the liver. Human lung microsomes did not show glucuronidation activity towards BPA. While the liver intrinsic clearance was very high (857 mL min(-1)kg body weight(-1)), the tissue intrinsic clearances for the kidney and intestine were less than 1% of liver intrinsic clearance. Since BPA is a UGT1A1 substrate, we postulated that the common UGT1A1*28 polymorphism influences BPA glucuronidation, and consequently, BPA detoxification. Hepatic tissue intrinsic clearances for UGT1A1*1/*1, UGT1A1*1/*28, and UGT1A1*28/*28 microsomes were 1113, 1075, and 284 mL min(-1)kg body weight(-1), respectively. Prior to microsomal experiments, the bioproduction of BPAG and stable isotope-labeled BPAG (BPAG(d16)) was performed for the purpose of the reliable and accurate quantification of BPAG. In addition, a sensitive LC-MS/MS analytical method for the simultaneous determination of BPA and BPAG based on two stable isotope-labeled internal standards was developed and validated. In conclusion, our in vitro results show that the liver is the main site of BPA glucuronidation (K(m) 8.9 ?M, V(max) 8.5 nmol min(-1) mg(-1)) and BPA metabolism may be significantly influenced by a person's genotype (K(m) 10.0-13.1 ?M, V(max) 3.4-16.2 nmol min(-1) mg(-1)). This discovery may be an important fact for the currently on-going worldwide BPA risk assessments and for the improvement of physiologically based pharmacokinetic models. PMID:22154984

Trdan Lušin, Tina; Roškar, Robert; Mrhar, Aleš

2011-12-01

263

Development of a liquid chromatography-tandem mass spectrometry method for the determination of 23 endogenous steroids in small quantities of primate urine.  

PubMed

A quantitative method using liquid chromatography-tandem mass spectrometry (LC-MS-MS) was developed for the simultaneous determination of 23 endogenous steroids in primate urine. The introduced method includes estrone, pregnandiol, cortisol, testosterone and several human urinary glucocorticoid and androgen metabolites. As the method is intended for the analysis of steroid hormones in behavioral studies on wild-living primates, it was adapted for a sample volume of 200microL urine. The sample preparation consisted of an enzymatic hydrolysis of steroid glucuronides using beta-glucuronidase from E. coli followed by a solvolytic cleavage of steroid sulfates employing sulfuric acid/ethyl acetate. The extraction of steroids from urine was optimized with respect to pH during extraction, type of ether and the amount of enzyme necessary for complete hydrolysis of glucuronides. The recovery of steroids spiked into urine before hydrolysis was 58.9-103.7% with an intra-day precision of 2.7-14.3% and an inter-day precision of 2.9-14.8%. Detection limits ranged from 0.1-0.5ng/mL. The reproducibility of the whole sample preparation process was also demonstrated for unspiked urine (CV 1.2-16.5%). The proportion of steroid hormone excreted as sulfate was determined for 21 steroids in chimpanzee urine. The solvolysis proved to be essential for all investigated steroids except for pregnandiol, tetrahydrocortisol and tetrahydrocortisone, which were found to be less then 10% in the solvolysis fraction. PMID:18054529

Hauser, Barbara; Deschner, Tobias; Boesch, Christophe

2007-11-19

264

Glucuronidation as a Mechanism of Intrinsic Drug Resistance in Human Colon Cancer: Reversal of Resistance by Food Additives  

Microsoft Academic Search

Colon cancer exhibits inherent insensitivity to chemotherapy by mech- anisms that are poorly characterized. We have shown that human colon cancer cells are efficient in drug conjugation catalyzed by UDP-glucu- ronosyltransferases (UGTs) and now report on the role of glucuronidation in de novo resistance to two topoisomerase I inhibitors. Identification of the UGT responsible for glucuronidation of SN-38 and the

Jeffrey Cummings; Brian T. Ethell; Lesley Jardine; Gary Boyd; Janet S. Macpherson; Brian Burchell; John F. Smyth; Duncan I. Jodrell

2003-01-01

265

In vitro characterization of glucuronidation of vanillin: identification of human UDP-glucuronosyltransferases and species differences.  

PubMed

Vanillin is a food flavoring agent widely utilized in foods, beverages, drugs, and perfumes and has been demonstrated to exhibit multiple pharmacological activities. Given the importance of glucuronidation in the metabolism of vanillin, the UDP-glucuronosyltransferase conjugation pathway of vanillin was investigated in this study. Vanillin glucuronide was identified by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and a hydrolysis reaction catalyzed by ?-glucuronidase. The kinetic study showed that vanillin glucuronidation by HLMs and HIMs followed Michaelis-Menten kinetics and the kinetic parameters were as follows: 134.9?±?13.5??M and 81.3?±?11.3??M for K(m) of HLMs and HIMs, 63.8?±?2.0?nmol/min/mg pro and 13.4 ±2.0?nmol/min/mg pro for Vmax of HLMs and HIMs. All UDP-glucuronosyltransferase (UGT) isoforms except UGT1A4, 1A9, and 2B7 showed the capability to glucuronidate vanillin, and UGT1A6 exerted the higher V(max)/K(m) values than other UGT isoforms for the glucuronidation of vanillin when assuming expression of isoforms is similar in recombinant UGTs. Kinetic analysis using liver microsomes from six studied speices indicated that vanillin had highest affinity for the monkey liver microsomes enzyme (K(m) ?=?25.6?±?3.2??M) and the lowest affinity for the mice liver microsomes enzyme (K(m) ?=?149.1?±?18.4??M), and intrinsic clearance was in the following order: monkey?>?dog?>?minipig?>?mice?>?rat?~?human. These data collectively provided important information for understanding glucuronidation of vanillin. PMID:23184728

Yu, Jian; Han, Jing-Chun; Hua, Li-Min; Gao, Ya-Jie

2012-11-26

266

In vitro and in vivo oxidative metabolism and glucuronidation of anastrozole  

PubMed Central

AIMS Little information is available regarding the metabolic routes of anastrozole and the specific enzymes involved. We characterized anastrozole oxidative and conjugation metabolism in vitro and in vivo. METHODS A sensitive LC-MS/MS method was developed to measure anastrozole and its metabolites in vitro and in vivo. Anastrozole metabolism was characterized using human liver microsomes (HLMs), expressed cytochrome P450s (CYPs) and UDP-glucuronosyltransferases (UGTs). RESULTS Hydroxyanastrozole and anastrozole glucuronide were identified as the main oxidative and conjugated metabolites of anastrozole in vitro, respectively. Formation of hydroxyanastrozole from anastrozole was markedly inhibited by CYP3A selective chemical inhibitors (by >90%) and significantly correlated with CYP3A activity in a panel of HLMs (r = 0.96, P = 0.0005) and mainly catalyzed by expressed CYP3A4 and CYP3A5. The Km values obtained from HLMs were also close to those from CYP3A4 and CYP3A5. Formation of anastrozole glucuronide in a bank of HLMs was correlated strongly with imipramine N-glucuronide, a marker of UGT1A4 (r = 0.72, P < 0.0001), while expressed UGT1A4 catalyzed its formation at the highest rate. Hydroxyanastrozole (mainly as a glucuronide) and anastrozole were quantified in plasma of breast cancer patients taking anastrozole (1 mg day?1); anastrozole glucuronide was less apparent. CONCLUSION Anastrozole is oxidized to hydroxyanastrozole mainly by CYP3A4 (and to some extent by CYP3A5 and CYP2C8). Once formed, this metabolite undergoes glucuronidation. Variable activity of CYP3A4 (and probably UGT1A4), possibly due to genetic polymorphisms and drug interactions, may alter anastrozole disposition and its effects in vivo.

Kamdem, Landry K; Liu, Yong; Stearns, Vered; Kadlubar, Susan A; Ramirez, Jacqueline; Jeter, Stacie; Shahverdi, Karineh; Ward, Bryan A; Ogburn, Evan; Ratain, Mark J; Flockhart, David A; Desta, Zeruesenay

2010-01-01

267

Determination of t,t-muconic acid in urine samples using a molecular imprinted polymer combined with simultaneous ethyl chloroformate derivatization and pre-concentration by dispersive liquid-liquid microextraction.  

PubMed

The present communication describes the preparation and evaluation of a molecularly imprinted polymer (MIP) as a solid-phase extraction (SPE) sorbent and simultaneous ethyl chloroformate (ECF) derivatization and pre-concentration by dispersive liquid-liquid microextraction (DLLME) for the analysis of t,t-muconic acid (t,t-MA) in urine samples using gas chromatography-mass spectrometry. The imprinting polymer was prepared using methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linker, 2,2-azobisisobutyronitrile as the initiator and t,t-MA as a template molecule. The imprinted polymer was evaluated for its use as a SPE sorbent by comparing both imprinted and non-imprinted polymers in terms of the recovery of t,t-MA from urine samples. Molecular modelling studies were performed in order to estimate the binding energy and efficiency of the MIP complex formed between the monomer and the t,t-MA. Various factors that can affect the extraction efficiency of MIP, such as the loading, washing and eluting conditions, were optimized; other factors that can affect the derivatization and DLLME pre-concentration were also optimized. MIP in combination with ECF derivatization and DLLME pre-concentration for t,t-MA exhibits good linearity, ranging from 0.125 to 2 ?g mL(-1) (R(2) = 0.9971), with limit of detection of 0.037 ?g mL(-1) and limit of quantification of 0.109 ?g mL(-1). Intra- and inter-day precision was found to be <6%. The proposed method has been proven to be effective and sensitive for the selective pre-concentration and determination of t,t-MA in urine samples of cigarette smokers. PMID:23079953

Mudiam, Mohana Krishna Reddy; Chauhan, Abhishek; Singh, Krishna P; Gupta, Shailendra K; Jain, Rajeev; Ch, Ratnasekhar; Murthy, R C

2012-10-19

268

Kinetic disposition of lorazepam with focus on the glucuronidation capacity, transplacental transfer in parturients and racemization in biological samples.  

PubMed

The present study investigates the kinetic disposition with focus on the racemization, glucuronidation capacity and the transplacental transfer of lorazepam in term parturients during labor. The study was conducted on 10 healthy parturients aged 18-37 years with a gestational age of 36-40.1 weeks, treated with a single oral dose of 2 mg racemic lorazepam 2-9 h before delivery. Maternal venous blood and urine samples were obtained over a 0-48 h interval and the umbilical cord sample was obtained immediately after clamping. Lorazepam enantiomers were determined in plasma and urine samples by LC-MS/MS using a Chiralcel OD-R column. In vitro racemization of lorazepam required the calculation of the pharmacokinetic parameters as isomeric mixtures. The data were fitted to two-compartment model and the pharmacokinetic parameters are reported as means (95% CI): t(1/2a) 3.2h (2.6-3.7 h), K(a) 0.23 h(-1) (0.19-0.28 h(-1)), t(1/2) 10.4h (9.4-11.3h), beta 0.068 h(-1) (0.061-0.075h(-1)), AUC(0-infinity) 175.3(ngh)/ml (145.7-204.8(ngh)/ml), Cl/F 2.6 ml/(minkg) (2.3-2.9 ml/(minkg)), Vd/F178.8l (146.5-211.1l), Fel 0.3% (0.1-0.5%), and Cl(R) 0.010 ml/(minkg) (0.005-0.015 ml/(minkg)). Placental transfer of lorazepam evaluated as the ratio of vein umbilical/maternal vein plasma concentrations, obtained as an isomeric mixture, was 0.73 (0.52-0.94). Pregnancy changes the pharmacokinetics of lorazepam, with an increase in the apparent distribution volume, an increase in apparent oral clearance, and a reduction of elimination half-life. The increase in oral clearance may indicate an increase in glucuronidation capacity, with a possible reduction in the plasma concentrations of drugs depending on glucuronidation capacity as the major metabolic pathway. PMID:16143486

Papini, Olga; da Cunha, Sergio Pereira; da Silva Mathes, Angelo do Carmo; Bertucci, Carlo; Moisés, Elaine Christine Dantas; de Barros Duarte, Luciana; de Carvalho Cavalli, Ricardo; Lanchote, Vera Lucia

2005-09-06

269

Characterization of afloqualone N-glucuronidation: species differences and identification of human UDP-glucuronosyltransferase isoform(s).  

PubMed

Afloqualone (AFQ) is one of the centrally acting muscle relaxants. AFQ N-glucuronide is the most abundant metabolite in human urine when administered orally, whereas it was not detected in the urine when administered to rats, dogs, and monkeys. Species differences in AFQ N-glucuronidation were investigated with liver microsomes obtained from humans and experimental animals. The kinetics of AFQ N-glucuronidation in human liver microsomes showed a typical Michaelis-Menten plot. The K(m) and V(max) values accounted for 2019 +/- 85.9 muM and 871.2 +/- 17.9 pmol/min/mg protein, respectively. The V(max) and intrinsic clearance (CL(int)) values of AFQ N-glucuronidation in human liver were approximately 4- to 10-fold and 2- to 4-fold higher than those in rat, dog, and monkey, respectively. Among 12 recombinant human UDP-glucuronosyltransferase (UGT) isoforms, both UGT1A4 and UGT1A3 exhibited high AFQ N-glucuronosyltransferase activities. The K(m) value of AFQ N-glucuronidation in recombinant UGT1A4 microsomes was very close to that in human liver microsomes. The formation of AFQ N-glucuronidation by human liver, jejunum, and recombinant UGT1A4 microsomes was effectively inhibited by trifluoperazine, a known specific substrate for UGT1A4. The AFQ N-glucuronidation activities in seven human liver microsomes were significantly correlated with trifluoperazine N-glucuronidation activities (r(2) = 0.798, p < 0.01). In contrast, the K(m) value of AFQ N-glucuronidation in recombinant UGT1A3 microsomes was relatively close to that in human jejunum microsomes. These results demonstrate that AFQ N-glucuronidation in human is mainly catalyzed by UGT1A4 in the liver and by UGT1A3, as well as UGT1A4 in the intestine. PMID:15475412

Kaji, Hidefumi; Kume, Toshiyuki

2004-10-08

270

21 CFR 172.868 - Ethyl cellulose.  

Code of Federal Regulations, 2013 CFR

...Multipurpose Additives § 172.868 Ethyl cellulose. The food additive ethyl cellulose may be safely used in food in accordance...conditions: (a) The food additive is a cellulose ether containing ethoxy (OC2 H5 ) groups...

2013-04-01

271

21 CFR 172.868 - Ethyl cellulose.  

Code of Federal Regulations, 2010 CFR

...Multipurpose Additives § 172.868 Ethyl cellulose. The food additive ethyl cellulose may be safely used in food in accordance...conditions: (a) The food additive is a cellulose ether containing ethoxy (OC2 H5 ) groups...

2010-01-01

272

21 CFR 172.868 - Ethyl cellulose.  

Code of Federal Regulations, 2010 CFR

...Multipurpose Additives § 172.868 Ethyl cellulose. The food additive ethyl cellulose may be safely used in food in accordance...conditions: (a) The food additive is a cellulose ether containing ethoxy (OC2 H5 ) groups...

2009-04-01

273

21 CFR 573.420 - Ethyl cellulose.  

Code of Federal Regulations, 2010 CFR

...Food Additive Listing § 573.420 Ethyl cellulose. The food additive ethyl cellulose may be safely used in animal feed in accordance...conditions: (a) The food additive is a cellulose ether containing ethoxy (OC2 H5 ) groups...

2009-04-01

274

21 CFR 573.420 - Ethyl cellulose.  

Code of Federal Regulations, 2013 CFR

...Food Additive Listing § 573.420 Ethyl cellulose. The food additive ethyl cellulose may be safely used in animal feed in accordance...conditions: (a) The food additive is a cellulose ether containing ethoxy (OC2 H5 ) groups...

2013-04-01

275

Determination of a peroxisome proliferator-activated receptor ? agonist, 1-(trans-methylimino- N-oxy)-6-(2-morpholinoethoxy-3-phenyl-1H-indene-2-carboxylic acid ethyl ester (KR62980) in rat plasma by liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

A novel peroxisome proliferator-activated receptor ? (PPAR?) agonist, KR-62980, was determined by liquid–liquid extraction with ethyl acetate and liquid chromatography–tandem mass spectrometry (LC\\/MS\\/MS) in rat plasma. In order to evaluate the pharmacokinetics of KR-62980, a reliable, selective and sensitive high-performance liquid chromatographic method with electrospray ionization tandem mass spectrometry was developed for the quantification of KR-62980 in rat plasma. KR-62980

Min-Sun Kim; Jin Sook Song; Hyeongjin Roh; Jong-Shik Park; Jin Hee Ahn; Sung-Hoon Ahn; Myung Ae Bae

2011-01-01

276

Glucuronide and sulfate conjugates of ICI 182,780, a pure anti-estrogenic steroid. Order of addition, catalysis and substitution effects in glucuronidation  

Microsoft Academic Search

The 3-sulfate 4 and 3- and 17-glucuronide conjugates 5 and 6 of the pure anti-estrogenic steroid ICI 182,780 1, which is expected to be an effective agent for the treatment of breast cancer, have been prepared. The synthesis of 6 could only be satisfactorily achieved using an inverse addition technique, not previously employed in the glucuronic acid series: the value

John R Ferguson; John R Harding; Keith W Lumbard; Feodor Scheinmann; Andrew V Stachulski

2000-01-01

277

Aryl ethyl ethers prepared by ethylation using diethyl carbonate  

Microsoft Academic Search

An environmentally more convenient reaction for the production of industrially important aryl ethyl ethers (ArOEts) is described. ArOEts were selectively obtained in essentially quantitative yields by the reaction of corresponding (hetero)aromatic alcohols (ArOHs) with diethyl carbonate as the environmentally friendly alkylating reagent in the presence of N,N-dimethylacetamide used as polar aprotic cosolvent, and sodium ethoxide as the base. The reactions

T. Weidlich; M. Pokorný; Z. Pad?lková; A. R?ži?ka

2007-01-01

278

A Method for the Determination of 1-Naphthol in Urine.  

National Technical Information Service (NTIS)

Humans exposed industrially to the insecticide carbaryl (1-naphthyl N-methylcarbamate) excrete relatively large quantities of 1-naphthol conjugated either as the sulfate or glucuronide. A colorimetric procedure is generally used to quantitatively determin...

M. T. Shafik H. C. Sullivan H. F. Enos

1971-01-01

279

Expression of ?-glucuronidase on the surface of bacteria enhances activation of glucuronide prodrugs.  

PubMed

Extracellular activation of hydrophilic glucuronide prodrugs by ?-glucuronidase (?G) was examined to increase the therapeutic efficacy of bacteria-directed enzyme prodrug therapy (BDEPT). ?G was expressed on the surface of Escherichia coli by fusion to either the bacterial autotransporter protein Adhesin (membrane ?G (m?G)/AIDA) or the lipoprotein (lpp) outermembrane protein A (m?G/lpp). Both m?G/AIDA and m?G/lpp were expressed on the bacterial surface, but only m?G/AIDA displayed enzymatic activity. The rate of substrate hydrolysis by m?G/AIDA-BL21cells was 2.6-fold greater than by p?G-BL21 cells, which express periplasmic ?G. Human colon cancer HCT116 cells that were incubated with m?G/AIDA-BL21 bacteria were sensitive to a glucuronide prodrug (p-hydroxy aniline mustard ?-D-glucuronide, HAMG) with an half maximal inhibitory concentration (IC50) value of 226.53±45.4??M, similar to the IC50 value of the active drug (p-hydroxy aniline mustard, pHAM; 70.6±6.75??M), indicating that m?G/AIDA on BL21 bacteria could rapidly and efficiently convert HAMG to an active anticancer agent. These results suggest that surface display of functional ?G on bacteria can enhance the hydrolysis of glucuronide prodrugs and may increase the effectiveness of BDEPT. PMID:23598434

Cheng, C-M; Chen, F M; Lu, Y-L; Tzou, S-C; Wang, J-Y; Kao, C-H; Liao, K-W; Cheng, T-C; Chuang, C-H; Chen, B-M; Roffler, S; Cheng, T-L

2013-04-19

280

Efficient synthesis of glycyrrhetinic acid glycoside/glucuronide derivatives using silver zeolite as promoter.  

PubMed

3-O-Glycopyranosides of glycyrrhetinic acid have been synthesized in good to high yields and excellent stereoselectivity using glycosyl bromide donors and silver zeolite as promoter. In addition to the preparation of glycosides containing beta-linked glucosyl, 2-deoxy-2-trichloroacetamido-glucosyl, galactosyl, cellobiosyl and lactosyl residues, also the deactivated acetylated methyl glucopyranosyluronate bromide donor could be coupled to triterpene aglycon ester derivatives in good yields. The ester protecting group located at C-30 of the oleanolic acid scaffold exerted an influence on the overall yield, with the methylester-protected glycosyl acceptor giving better yields compared to the allyl, benzyl as well as diphenylmethyl ester aglycon. The acetyl-protected glucuronides were differently deblocked in high yields via Zemplén deacetylation or via hydrogenolysis followed by Zemplén deacetylation, and alkaline hydrolysis, respectively, to allow for a selective liberation of the ester groups from either the glucuronide or the glycyrrhetinic acid unit, respectively. The target glycosides/glucuronides serve as probes for pharmaceutical studies aimed at defining structure-activity relationships of glycoside/glucuronide triterpenes. PMID:19428000

del Ruiz Ruiz, Maria Carmen; Amer, Hassan; Stanetty, Christian; Beseda, Igor; Czollner, Laszlo; Shah, Priti; Jordis, Ulrich; Kueenburg, Bernhard; Classen-Houben, Dirk; Hofinger, Andreas; Kosma, Paul

2009-04-20

281

Evaluation of Indoxyl-Beta-D-Glucuronide as a Chromogen in Media Specific for 'Escherichia coli'.  

National Technical Information Service (NTIS)

Indoxyl-beta-D-glucuronide (indoxyl) was evaluated as a specific chromogen for detection of Escherichia coli by the membrane filter method. In all, 413 colonies were tested from the indoxyl-supplemented media, yielding 93.3% confirmation, as E. coli. Comp...

J. R. Haines T. C. Covert C. C. Rankin

1993-01-01

282

The ABC-like vacuolar transporter for rye mesophyll flavone glucuronides is not species-specific  

Microsoft Academic Search

In many cases, the vacuolar uptake of secondary metabolites has been demonstrated to be strictly specific for a given compound and plant species. While most plants contain glycosylated secondary substances, few cases are known where flavonoids may also carry negative charges, e.g. as glucuronide conjugates. Vacuolar transport of glucosylated phenylpropanoid derivatives has been shown to occur by proton–substrate antiport mechanisms

Markus Klein; Enrico Martinoia; Gudrun Hoffmann-Thoma; Gottfried Weissenböck

2001-01-01

283

Interindividual and interethnic differences in the demethylation and glucuronidation of codeine.  

PubMed Central

1. The 8 h urinary excretion of codeine and seven of its metabolites was compared in 149 healthy Swedish Caucasians and 133 healthy Chinese following a single oral dose of 25 mg codeine phosphate. 2. The total 8 h urinary recovery of drug-related material was 74 +/- 24% in the Caucasians and 60 +/- 14% in the Chinese (P less than 0.001). The excretion of unchanged codeine was significantly higher in the Chinese (7.2%) compared with the Caucasians (4.3%, P less than 0.001). 3. The Caucasians excreted significantly greater proportions of codeine-6-glucuronide (C6G) (62%) than the Chinese (44%) (P less than 0.001). The frequency distribution of the log metabolic ratio (MR) for glucuronidation (codeine/C6G) was shifted towards higher values in the Chinese population. Males in both groups and Chinese smokers had significantly lower glucuronidation MRs than females and non-smokers in the respective populations (P less than 0.001). 4. The frequency distribution of the MR for O-demethylation (codeine/morphine (M) + M-3 and M-6-glucuronide (M3G and M6G) + normorphine (NM) was highly skewed in the Caucasians, suggestive of a bimodal distribution. There was a 160-fold interindividual variation in this MR. A unimodal distribution of the log O-demethylation MR was observed in Chinese. The Caucasians excreted less M and more M6G than did the Chinese (P less than 0.001). 5. Significantly more norcodeine (NC) and less NC-glucuronide (NCG) were excreted in the Chinese compared with the Caucasians (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Yue, Q Y; Svensson, J O; Alm, C; Sjoqvist, F; Sawe, J

1989-01-01

284

Health and Environmental Effects Profile for ethyl methacrylate  

SciTech Connect

The Health and Environmental Effects Profile for ethyl methacrylate was prepared to support listings of hazardous constituents of a wide range of waste streams under Section 3001 of the Resource Conservation and Recovery Act (RCRA) and to provide health-related limits for emergency actions under Section 101 of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). Both published literature and information obtained from Agency program office files were evaluated as they pertained to potential human health, aquatic life and environmental effects. Quantitative estimates are presented provided sufficient data are available. Ethyl methacrylate has been determined to be a systemic toxicant. An acceptable daily intake (ADI) for ethyl methacrylate is 0.086 mg/kg/day for oral exposure.

Not Available

1986-06-01

285

Ethyl acetate: X-ray, solvent and computed structures.  

PubMed

Ethyl acetate (ethyl ethanoate) was crystallized in situ and the crystal structure was determined. In the solid, the molecule is flat with trans conformation. The geometric details of ethyl acetate as a solvate are analyzed statistically using the Cambridge Structural Database, uncovering a high degree of hidden disorder. Despite the disorder, they exhibit a preference of the trans over the gauche isomer, with a negligible contribution of the cis isomer. These results are compared to ab initio calculations on both solid-state and molecular level. For the molecular structures, the computed energy differences of the isomers match the statistics found as a solvent. Several DFT-D2 methods used to calculate the solid state yield results that differ significantly from the experiment. PMID:23108979

Boese, A Daniel; Kirchner, Michael; Echeverria, Gustavo A; Boese, Roland

2012-10-25

286

Simultaneous quantification of atomoxetine as well as its primary oxidative and O-glucuronide metabolites in human plasma and urine using liquid chromatography tandem mass spectrometry (LC\\/MS\\/MS)  

Microsoft Academic Search

A sensitive and selective liquid chromatography tandem mass spectrometry (LC\\/MS\\/MS) method for the determination of atomoxetine and its metabolites (4-hydroxyatomoxetine, N-des-methylatomoxetine, and 4-hydroxyatomoxetine-O-glucuronide) has been developed for human plasma and urine. Using stable-labeled internal standards, the method proved to be accurate and precise for the analytes in all species, resulting in inter-batch accuracy (percent relative error, %RE) within 100±13% and

John H. Mullen; Richard L. Shugert; George D. Ponsler; Qimin Li; Bhaskar Sundaram; Heather L. Coales; Joseph E. Yakupkovic; Richard M. LeLacheur; William J. Wheeler; Frank J. Belas; John-Michael Sauer

2005-01-01

287

Determination of low level methyl tert-butyl ether, ethyl tert-butyl ether and methyl tert-amyl ether in human urine by HS-SPME gas chromatography\\/mass spectrometry  

Microsoft Academic Search

Methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) are oxygenated compounds added to gasoline to enhance octane rating and to improve combustion. They may be found as pollutants of living and working environments. In this work a robotized method for the quantification of low level MTBE, ETBE and TAME in human urine was developed and

Licia Scibetta; Laura Campo; Rosa Mercadante; Vito Foà; Silvia Fustinoni

2007-01-01

288

Vapor–liquid equilibrium of carbon dioxide with ethyl caproate, ethyl caprylate and ethyl caprate at elevated pressures  

Microsoft Academic Search

Vapor–liquid equilibrium (VLE) data were measured for CO2 with ethyl caproate, ethyl caprylate, and ethyl caprate using a semi-flow type apparatus at 308.2, 318.2 and 328.2 K over the pressure range from 1.6 to 9.2 MPa. In this paper, VLE data are reported. The VLE data were also correlated using the Soave–Redlich–Kwong and the Peng–Robinson equations of state with various

Weng-Hong Hwu; Jaw-Shin Cheng; Kong-Wei Cheng; Yan-Ping Chen

2004-01-01

289

An automatic 96-well solid phase extraction and liquid chromatography–tandem mass spectrometry method for the analysis of morphine, morphine-3-glucuronide and morphine-6-glucuronide in human plasma  

Microsoft Academic Search

A bioanalytical method using automated sample transferring, automated solid phase extraction (SPE) and liquid chromatography–tandem mass spectrometry (LC-MS-MS) was developed for morphine (MOR), and its metabolites morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) in human plasma. Samples of 0.25 ml were transferred into 96-well plate using automatic liquid handler (Multiprobe™ II). Automated SPE was carried out on a 96-channel programmable liquid handling

Wilson Z. Shou; Mary Pelzer; Tom Addison; Xiangyu Jiang; Weng Naidong

2002-01-01

290

Non-opioid induction of morphine-6-glucuronide synthesis is elicited by prolonged exposure of rat hepatocytes to heroin  

Microsoft Academic Search

BackgroundLiver metabolism of morphine leads to the formation of morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), the latter possessing strong opioid activity that however differs from that of the parent compound. In previous studies conducted in rats we have shown that repeated in vivo exposure to phenanthrene class of mu opioid receptor (MOR) agonists or antagonists (heroin, morphine, and naltrexone), but not

Manuela Graziani; Letizia Antonilli; Anna Rita Togna; Valentina Brusadin; Stefania Viola; Giuseppina Togna; Aldo Badiani; Paolo Nencini

2008-01-01

291

Enhanced ethyl butyrate production using immobilized lipase.  

PubMed

Abstract In this study, the production of ethyl butyrate was investigated by using immobilized lipase enzyme in shake flasks. In order to determine optimum conditions for the production, response surface methodology was used. The model indicated the optimum conditions for maximum conversion (9.1%) at the 0.31 M substrate concentration, acid- alcohol molar ratio of 0.49, immobilized enzyme 25% (w/v) at 35°C, for 3 hours which were in good agreement with the experimental value. At the end of the 55 hours conversion was obtained as 61.3%. When Na2HPO4 was used in reaction medium conversion increased to 90.3% for 55 hours. PMID:23305408

Ate?, Selma; Türk, Burcu; Bayraktar, Emine; Güvenç, Afife

2013-01-10

292

Health and environmental-effects profile for methyl ethyl ketone  

SciTech Connect

The Health and Environmental Effects Profile for methyl ethyl ketone was prepared by the Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office, Cincinnati, OH for the Office of Solid Waste and Emergency Response to support listings of hazardous constituents of a wide range of waste streams under Section 3001 of the Resource Conservation and Recovery Act (RCRA) and to provide health-related limits for emergency actions under Section 101 of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). Both published literature and information obtained from Agency program office files were evaluated as they pertained to potential human health, aquatic life, and environmental effects of hazardous-waste constituents. Quantitative estimates are presented, provided sufficient data are available. Methyl ethyl ketone has been determined to be a systemic toxicant. An Acceptable Daily Intake (ADI), defined as the amount of a chemical to which humans can be exposed on a daily basis over an extended period of time (usually a lifetime) without suffering a deleterious effect, for methyl ethyl ketone is 3.2 mg/day for oral exposure. The Reportable Quantity (RQ) value of 1, 10, 100, 1000, or 5000 pounds is used to determine the quantity of a hazardous substance for which notification is required in the event of a release as specified by CERCLA based on chronic toxicity. The RQ value for methyl ethyl ketone is 1000.

Not Available

1985-09-01

293

Ethyl Carbamate Preventative Action Manual (Italian language ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... Citrulline Production And Ethyl Carbamate (Urethane) Precursor Formation From Arginine Degradation By Wine Lactic Acid Bacteria Leuconostoc ... More results from www.fda.gov/food/foodborneillnesscontaminants/chemicalcontaminants

294

Morpholine-4-carboxamidinium ethyl carbonate  

PubMed Central

The asymmetric unit of the title salt, C5H12N3O+·C3H5O3 ?, contains two carboxamidinium and two ethyl carbonate ions. In the crystal, the C—N bond lengths in the central CN3 units of the cations range between 1.324?(2) and 1.352?(2)?Å, indicating partial double-bond character. The central C atoms are bonded to the three N atoms in a nearly ideal trigonal–planar geometry and the positive charges are delocalized in the CN3 planes. The morpholine rings are in chair conformations. The C—O bond lengths in both ethyl carbonate ions are characteristic for delocalized double bonds [1.243?(2)–1.251?(2)?Å] and typical single bonds [1.368?(2) and 1.375?(2)?Å]. In the crystal, N—H?O hydrogen bonds between cations and anions generate a two-dimensional network in the ac plane.

Tiritiris, Ioannis

2012-01-01

295

Hormonal monitoring of early pregnancy by a direct radioimmunoassay of steroid glucuronides in first morning urine  

SciTech Connect

The usefulness of the direct 4-hour radioimmunoassay of estriol-16-glucuronide (E/sub 3/G) and pregnanediol-3-glucuronide (P/sub 2/G) in first morning urine (FMU) for establishing a prognosis of the early pregnancy outcome was evaluated in 106 patients that became pregnant. Microaliquots of FMU were serially assayed from day 3 of the conception cycle until day 80 of pregnancy. The E/sub 3/G and P/sub 2/G profiles of 19 pregnancies which terminated in spontaneous abortion with either a diagnosis of the blighted ovum syndrome (n = 11) or presumption of a corpus luteum/trophoblast failure (n = 8) have been compared with those of clinically normal pregnancies (n = 87). Normal pregnancies displayed typical patterns of E/sub 3/G and P/sub 2/G development, while variations were observed in abortive events that reflected changes of the fetoplacental unit.

Mendizabal, A.F.; Quiroga, S.; Farinati, Z.; Lahoz, M.; Nagle, C.

1984-11-01

296

Microwave rotational spectrum and internal rotation in gauche ethyl alcohol  

Microsoft Academic Search

The microwave torsional-rotational spectra of several species of gauche ethyl alcohol have been assigned and analyzed. The species studied are CH3CH2OH, CH3CH2OD, CH2DCH2OH, and CH2DCH2OD, both methyl symmetric and asymmetric forms of the last two species. Rotational coefficients have been determined for all species. For the normal species, the components of the dipole moment have been determined as ||mua||=1.264+\\/-0.010 D,

Ramesh K. Kakar; C. Richard Quade

1980-01-01

297

Synthesis and biological evaluations of a monomethylauristatin E glucuronide prodrug for selective cancer chemotherapy.  

PubMed

We developed a glucuronide prodrug of the potent monomethylauristatin E (MMAE). This prodrug is significantly less toxic than the parent drug. However, in the presence of ?-glucuronidase the prodrug leads to the efficient release of MMAE thereby triggering a subnanomolar cytotoxic activity against several cancer cell lines. Preliminary in vivo experiments conducted in C57BL/6 mice bearing a subcutaneous murine Lewis Lung Carcinoma (LLC) demonstrated the potential of this targeting system for the selective treatment of solid tumors. PMID:23845743

Legigan, Thibaut; Clarhaut, Jonathan; Renoux, Brigitte; Tranoy-Opalinski, Isabelle; Monvoisin, Arnaud; Jayle, Christophe; Alsarraf, Jérôme; Thomas, Mikaël; Papot, Sébastien

2013-06-25

298

Menthol-?-D-Glucuronide: A Potential Prodrug for Treatment of the Irritable Bowel Syndrome  

Microsoft Academic Search

Menthol-ß-D-glucuronide is a potential prodrug for colonic delivery of the spasmolytic agent menthol. Menthol is the primary constituent of peppermint oil, which is used to treat the irritable bowel syndrome. The chemical stability of menthol-ß-D-glucuromde was assessed at various pHs (1.5,4.5, 6.0 and 7.4) over a 4 to 24 h period at 37°C. The prodrug was stable, i.e., there was

Harold W. Nolen III; David R. Friend

1994-01-01

299

Direct radioiodination of metabolic 8-hydroxy-quinolyl-glucuronide, as a potential anti-cancer drug  

Microsoft Academic Search

8-Hydroxy-quinolyl-glucuronide (8-HOQ-Glu) can be deglucuronidated by the ?-glucoronidase enzyme, which has an activity that is considerably high in certain kinds of cancer cell. Owing to this enzyme activity, 8-HOQ-Glu can be considered as a potential anti-cancer drug. The combination of the radiotoxicity known of 125I nuclide with the cytotoxicity of 8-hydroxy-quinoline (8-HOQ) and particularly the selective carrying of 125I into

Turan Ünak

1996-01-01

300

Synthesis of an estradiol glucuronide derivative and investigation of its radiopharmaceutical potential  

Microsoft Academic Search

The aim of the current study was to synthesize a derivative of estradiol glucuronide, which is able to be labeled with 99mTc and to investigate its radiopharmaceutical potential using imaging and biodistribution studies. An estrogen derivative, ?-estradiol (1,3,5,[10]-estratriene-3,17?-diol) attached to diethylenetriamine pentaacetic acid (DTPA) was synthesized in six steps. At the end of these steps a compound of estradiol and

F. Z. Biber; P. Unak; T. Ertay; E. I. Medine; F. Zihnioglu; C. Tasc?; H. Durak

2006-01-01

301

Extensive intestinal glucuronidation of raloxifene in vivo in pigs and impact for oral drug delivery.  

PubMed

In this study an advanced multisampling site pig model, with simultaneous venous blood sampling pre- and post liver, was applied to quantify the role of the intestine in relation to the liver in first-pass glucuronidation of raloxifene in vivo. The pharmacokinetic of raloxifene (a BCS/BDDCS class II compound) in humans is characterized by extensive metabolism (>90%) and the major metabolite is the 4'-?-glucuronide (R-4-G). Following intra-jejunal (i.j.) single dose administration in pigs raloxifene was metabolized in the gut (E(G)) during first-pass to more than 70% and a high concentration (AUC(0-6 h) ratio R-4-G/raloxifene >100) of R-4-G was reached in the portal vein. The hepatic extraction (E(H)) of raloxifene was ~50% and as in humans the bioavailability become low (~7%) in pigs. Interestingly the E(H) of raloxifene and R-4-G was time-dependent after i.j. administration. It is clear that the gut was the dominating organ in first-pass extraction of raloxifene in vivo in pigs. The quantification in this study support earlier human data and emphasize that intestinal glucuronidation should be considered early in the pharmaceutical development. PMID:22559211

Thörn, Helena Anna; Yasin, Mohammed; Dickinson, Paul Alfred; Lennernäs, Hans

2012-05-04

302

Density, refractive index and speed of sound for mixtures of ethyl acetate with 2-butanol and 3-methyl-1-butanol  

Microsoft Academic Search

Densities, refractive indices and speeds of sound at 298.15, 303.15, and 308.15K are reported for the binary mixtures ethyl acetate + 2-butanol and ethyl acetate + 3-methyl-1-butanol. Isobaric vapor–liquid equilibrium data at 101.3kPa were determined for the ethyl acetate + 3-methyl-1-butanol system. Excess molar volumes, refractive index deviations and changes of speed of sound on mixing were calculated from experimental

José M Resa; Cristina González; Marina Juez; Salomé Ortiz de Landaluce

2004-01-01

303

Changes in Transpiration induced by Ethyl Alcohol  

Microsoft Academic Search

ETHYL alcohol was used as an auxiliary solvent in the preparation of auxin solutions for a series of transpiration experiments with plants in water culture when the roots were supplied with different auxins at varying concentrations. This method appears to be fairly common for auxin studies1,2. After weighing, the auxin is dissolved in a small quantity of ethyl alcohol, and

S. Allerup

1962-01-01

304

Piperidine-1-carboxamidinium ethyl carbonate  

PubMed Central

In the title salt, C6H14N3 +·C3H5O3 ?, the C—N bond lengths in the central CN3 unit of the carboxamidinium cation are 1.3262?(18), 1.3359?(18) and 1.3498?(18)?Å, indicating partial double-bond character. The central C atom is bonded to the three N atoms in a nearly ideal trigonal–planar geometry and the positive charge is delocalized in the CN3 plane. The piperidine ring is in a chair conformation. The C—O bond lengths in the ethyl carbonate anion are characteristic for a delocalized double bond and a typical single bond. In the crystal, N—H?O hydrogen bonds between cations and anions generate a two-dimensional network in the direction of the ab plane, whereas adjacent ion pairs form chains running along the b axis.

Tiritiris, Ioannis

2012-01-01

305

40 CFR 180.441 - Quizalofop ethyl; tolerances for residues.  

Code of Federal Regulations, 2013 CFR

...Tolerances are established for residues of the herbicide quizalofop ethyl, including its...Tolerances are established for residues of the herbicide quizalofop ethyl, including...registration are established for residues of the herbicide quizalofop ethyl,...

2013-07-01

306

IN VIVO RATE OF PHENOL GLUCURONIDATION BY RAINBOW TROUT  

EPA Science Inventory

Induction of vitellogenin (VTG) in male fish has become an accepted biomarker for xenoestrogenicity. This study utilized the male rainbow trout liver slice model to determine the estrogenicity of parent compound, methoxychlor (MXC) and metabolites, di-hydroxy methoxychlor (HPTE) ...

307

Stereoselective Hepatic Disposition of Model Diastereomeric Acyl Glucuronides  

Microsoft Academic Search

Numerous studies have previously been conducted with the impulse-response isolated perfused rat liver (IR-IPRL) to establish the role of both physiological and physicochemical factors in determining solutes' pattern of hepatic disposition, however the impact of optical isomerism on hepatic disposition has hardly been studied using this methodology. In this study, the IR-IPRL was used to assess the extent of stereoselectivity

David M. Shackleford; Roger L. Nation; R. W. Milne; P. J. Hayball; Allan M. Evans

2004-01-01

308

Resveratrol 3-O-d-glucuronide and resveratrol 4'-O-d-glucuronide inhibit colon cancer cell growth: Evidence for a role of A3 adenosine receptors, cyclin D1 depletion, and G1 cell cycle arrest.  

PubMed

SCOPE: Resveratrol is a plant-derived polyphenol with chemotherapeutic properties in animal cancer models and many biochemical effects in vitro. Its bioavailability is low and raises the possibility that the metabolites of resveratrol have biological effects. Here we investigate the actions of resveratrol 3-O-d-glucuronide, resveratrol 4'-O-d-glucuronide, and resveratrol 3-O-d-sulfate on the growth of colon cancer cells in vitro. METHODS AND RESULTS: The growth of Caco-2, HCT-116, and CCL-228 cells was measured using the neutral red and MTT assays. Resveratrol and each metabolite inhibited cell growth with IC50 values of 9.8-31 ?M. Resveratrol caused S phase arrest in all three cell lines. Resveratrol 3-O-d-glucuronide and resveratrol 4'-O-d-glucuronide caused G1 arrest in CCL-228 and Caco-2 cells. Resveratrol 3-O-d-sulfate had no effect on cell cycle. Growth inhibition was reversed by an inhibitor of AMP-activated protein kinase (compound C) or an adenosine A3 receptor antagonist (MRS1191). The A3 receptor agonist 2Cl-IB-MECA inhibited growth and A3 receptors were detected in all cell lines. The resveratrol glucuronides also reduced cyclin D1 levels but at higher concentrations than in growth experiments and generally did not increase phosphorylated AMP-activated protein kinase. CONCLUSION: Resveratrol glucuronides inhibit cell growth by G1 arrest and cyclin D1 depletion, and our results strongly suggest a role for A3 adenosine receptors in this inhibition. PMID:23650147

Polycarpou, Elena; Meira, Lisiane B; Carrington, Simon; Tyrrell, Elizabeth; Modjtahedi, Helmout; Carew, Mark A

2013-05-01

309

Pervaporation separation of ethyl acetate–ethanol binary mixtures using polydimethylsiloxane membranes  

Microsoft Academic Search

Pervaporation separation of azeotrope forming ethyl acetate–ethanol mixtures was investigated by using a selfmade polydimethylsiloxane (PDMS) membrane. Sorption, desorption and pervaporation experiments for ethyl acetate–ethanol mixture with different concentrations were conducted at 30, 40 and 50°C. The effect of process parameters such as feed concentration and temperature on flux and selectivity is discussed. Equilibrium curves are determined by vapor–liquid equilibrium

A. Hasano?lu; Y. Salt; S. Kele?er; S. Özkan; S. Dinçer

2005-01-01

310

Ethyl hexanoate transfer in paper and plastic food packaging by sorption and permeation experiments  

Microsoft Academic Search

The barrier properties of one treated paper packaging and one standard plastic film (bi-oriented polypropylene, biOPP) were assessed for ethyl hexanoate. Three methods based either on sorption (gravimetry and micro-atmosphere-derived method) or permeation kinetic determination were used in controlled conditions of aroma vapor concentration (107Pa), temperature (25°C) and relative humidity (about 0 %). Ethyl hexanoate solubility values were on the

Cécile Dury-Brun; Yuichi Hirata; Valérie Guillard; Violette Ducruet; Pascale Chalier; Andrée Voilley

2008-01-01

311

Transesterification of Fish Oil to Produce Fatty Acid Ethyl Esters Using Ultrasonic Energy  

Microsoft Academic Search

This study evaluated the production of fatty acid ethyl esters from fish oil using ultrasonic energy and alkaline catalysts\\u000a dissolved in ethanol. The feasibility of fatty acid ethyl ester production was determined using an ultrasonic bath and probe,\\u000a and between 0.5 and 1% KOH (added to the fish oil). Furthermore, factors such as ultrasonic device (bath and probe), catalyst\\u000a (KOH

Roberto E. Armenta; Mircea Vinatoru; Adam M. Burja; Jaroslav A. Kralovec; Colin J. Barrow

2007-01-01

312

Inhibition of genistein glucuronidation by bisphenol A in human and rat liver microsomes.  

PubMed

Genistein is a natural phytoestrogen of the soybean, and bisphenol A (BPA) is a synthetic chemical used in the production of polycarbonate plastics. Both genistein and BPA disrupt the endocrine system in vivo and in vitro. Growing concerns of altered xenobiotic metabolism due to concomitant exposures from soy milk in BPA-laden baby bottles has warranted the investigation of the glucuronidation rate of genistein in the absence and presence (25 ?M) of BPA by human liver microsomes (HLM) and rat liver microsomes (RLM). HLM yield V(max) values of 0.93 ± 0.10 nmol · min(-1) · mg(-1) and 0.62 ± 0.05 nmol · min(-1) · mg(-1) in the absence and presence of BPA, respectively. K(m) values for genistein glucuronidation by HLM in the absence and presence of BPA are 15.1 ± 7.9 ?M and 21.5 ± 7.7 ?M, respectively, resulting in a K(i) value of 58.7 ?M for BPA. Significantly reduced V(max) and unchanged K(m) in the presence of BPA in HLM are suggestive of noncompetitive inhibition. In RLM, the presence of BPA resulted in a K(i) of 35.7 ?M, an insignificant change in V(max) (2.91 ± 0.26 nmol · min(-1) · mg(-1) and 3.05 ± 0.41 nmol · min(-1) · mg(-1) in the absence and presence of BPA, respectively), and an increase in apparent K(m) (49.4 ± 14 ?M with no BPA and 84.0 ± 28 ?M with BPA), indicative of competitive inhibition. These findings are significant because they suggest that BPA is capable of inhibiting the glucuronidation of genistein in vitro, and that the type of inhibition is different between HLM and RLM. PMID:22146138

Coughlin, Janis L; Thomas, Paul E; Buckley, Brian

2011-12-06

313

Influence of glucuronidation and reduction modifications of resveratrol on its biological activities.  

PubMed

Resveratrol (3,5,4'-trihydroxystilbene, RES), a star among dietary polyphenols, shows a wide range of biological activities, but it is rapidly and extensively metabolized into its glucuronide and sulfate conjugates as well as to the corresponding reduced products. This begs the question of whether the metabolites of RES contribute to its in vivo biological activity. To explore this possibility, we synthesized its glucuronidation (3-GR and 4'-GR) and reduction (DHR) metabolites, and evaluated the effect of these structure modifications on biological activities, including binding ability with human serum albumin (HSA), antioxidant activity in homogeneous solutions and heterogeneous media, anti-inflammatory activity, and cytotoxicity against various cancer cell lines. We found that 1) 4'-GR, DHR and RES show nearly equal binding to HSA, mainly through hydrogen bonding, whereas 3-GR adopts a quite different orientation mode upon binding, thereby resulting in reduced ability; 2) 3-GR shows comparable (even equal) ability to RES in FRAP- and AAPH-induced DNA strand breakage assays; DHR, 3-GR, and 4'-GR exhibit anti-hemolysis activity comparable to that of RES; additionally, 3-GR and DHR retain some degree activity of the parent molecule in DPPH.-scavenging and cupric ion-initiated oxidation of LDL assays, respectively; 3) compared to RES, 4'-GR displays equipotent ability in the inhibition of COX-2, and DHR presents comparable activity in inhibiting NO production and growth of SMMC-7721 cells. Relative to RES, its glucuronidation and reduction metabolites showed equal, comparable, or some degree of activity in the above assays, depending on the specific compound and test model, which probably supports their roles in contributing to the in vivo biological activities of the parent molecule. PMID:23703900

Lu, Dong-Liang; Ding, De-Jun; Yan, Wen-Jing; Li, Ran-Ran; Dai, Fang; Wang, Qi; Yu, Sha-Sha; Li, Yan; Jin, Xiao-Ling; Zhou, Bo

2013-05-23

314

In Vitro Glucuronidation of Fenofibric Acid by Human UDP-Glucuronosyltransferases and Liver Microsomes  

PubMed Central

Fenofibric acid (FA), the active moiety of fenofibrate, is an agonist of the peroxisome proliferator-activated nuclear receptor ? that modulates triglyceride and cholesterol profiles. Lipid response to fenofibrate and FA serum concentrations is highly variable. Although FA is reported to be almost exclusively inactivated by UDP-glucuronosyltransferases (UGTs) into FA-glucuronide (FA-G), the contribution of UGT isoenzymes has never been systematically assessed. Heterologously expressed human UGT1A and UGT2B and their coding variants were tested for FA glucuronidation using liquid chromatography/mass spectrometry. Recombinant UGT2B7 presented the highest Vmax/Km value (2.10 ?l/min/mg), 16-fold higher than the activity of other reactive UGTs, namely, UGT1A3, UGT1A6, and UGT1A9 (0.13, 0.09, and 0.02 ?l/min/mg, respectively). UGT2B7.1 (His268) and UGT2B7.2 (Tyr268) enzyme activity was similar, whereas UGT1A3.2 (R11A47), UGT1A3.3 (Trp11), and UGT1A9.3 (Thr33) showed 61 to 96% reduced Vmax/Km values compared with the respective (1) reference proteins. FA-G formation by a human liver bank (n = 48) varied by 10-fold, but the rate of formation was not associated with common genetic variations in UGT1A3, UGT1A6, UGT1A9, and UGT2B7. Correlation with activities for the probe substrates zidovudine (UGT2B7; r2 = 0.75), mycophenolic acid (UGT1A9; r2 = 0.42), fulvestrant (UGT1A3; r2 = 0.36), but not serotonin (UGT1A6; r2 = 0.06) indicated a primary role for UGT2B7 and lesser roles of UGT1A9 and UGT1A3 in hepatic FA glucuronidation. This was confirmed by a strong correlation of FA-G formation with UGT2B7 protein content and inhibition by fluconazole, a known UGT2B7 selective inhibitor. Additional studies are required to identify genetic factors contributing to the observed FA glucuronidation variability.

Tojcic, Jelena; Benoit-Biancamano, Marie-Odile; Court, Michael H.; Straka, Robert J.; Caron, Patrick

2009-01-01

315

[Toxicology of ethyl gasoline 78 and 94].  

PubMed

The authors have described clinical pictures of acute and chronic intoxication, especially toxic effect of ethyl gasoline upon nervous sytem, parenchymatous organs, and irritating effect on skin and mucous membranes. PMID:723613

Starzy?ski, Z; Szyma?ska, S; Jaraczewska, W; My?lak, Z

1978-01-01

316

Determination of low level methyl tert-butyl ether, ethyl tert-butyl ether and methyl tert-amyl ether in human urine by HS-SPME gas chromatography/mass spectrometry.  

PubMed

Methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) are oxygenated compounds added to gasoline to enhance octane rating and to improve combustion. They may be found as pollutants of living and working environments. In this work a robotized method for the quantification of low level MTBE, ETBE and TAME in human urine was developed and validated. The analytes were sampled in the headspace of urine by SPME in the presence of MTBE-d12 as internal standard. Different fibers were compared for their linearity and extraction efficiency: carboxen/polydimethylsiloxane, polydimethylsiloxane/divinylbenzene, and polydimethylsiloxane. The first, although highly efficient, was discarded due to deviation of linearity for competitive displacement, and the polydimethylsiloxane/divinylbenzene fiber was chosen instead. The analysis was performed by GC/MS operating in the electron impact mode. The method is very specific, with range of linearity 30-4600 ng L(-1), within- and between-run precision, as coefficient of variation, <22 and <16%, accuracy within 20% the theoretical level, and limit of detection of 6 ng L(-1) for all the analytes. The influence of the matrix on the quantification of these ethers was evaluated analysing the specimens of seven traffic policemen exposed to autovehicular emissions: using the calibration curve and the method of standard additions comparable levels of MTBE (68-528 ng L(-1)), ETBE (<6 ng L(-1)), and TAME (<6 ng L(-1)) were obtained. PMID:17386425

Scibetta, Licia; Campo, Laura; Mercadante, Rosa; Foà, Vito; Fustinoni, Silvia

2006-08-07

317

Optimization and validation of liquid chromatography and headspace-gas chromatography based methods for the quantitative determination of capsaicinoids, salicylic acid, glycol monosalicylate, methyl salicylate, ethyl salicylate, camphor and l-menthol in a topical formulation.  

PubMed

Capsaicinoids, salicylic acid, methyl and ethyl salicylate, glycol monosalicylate, camphor and l-menthol are widely used in topical formulations to relieve local pain. For each separate compound or simple mixtures, quantitative analysis methods are reported. However, for a mixture containing all above mentioned active compounds, no assay methods were found. Due to the differing physicochemical characteristics, two methods were developed and optimized simultaneously. The non-volatile capsaicinoids, salicylic acid and glycol monosalicylate were analyzed with liquid chromatography following liquid-liquid extraction, whereas the volatile compounds were analyzed with static headspace-gas chromatography. For the latter method, liquid paraffin was selected as compatible dilution solvent. The optimized methods were validated in terms of specificity, linearity, accuracy and precision in a range of 80% to 120% of the expected concentrations. For both methods, peaks were well separated without interference of other compounds. Linear relationships were demonstrated with R² values higher than 0.996 for all compounds. Accuracy was assessed by performing replicate recovery experiments with spiked blank samples. Mean recovery values were all between 98% and 102%. Precision was checked at three levels: system repeatability, method precision and intermediate precision. Both methods were found to be acceptably precise at all three levels. Finally, the method was successfully applied to the analysis of some real samples (cutaneous sticks). PMID:22094014

Pauwels, Jochen; D'Autry, Ward; Van den Bossche, Larissa; Dewever, Cédric; Forier, Michel; Vandenwaeyenberg, Stephanie; Wolfs, Kris; Hoogmartens, Jos; Van Schepdael, Ann; Adams, Erwin

2011-10-25

318

Identification of Recent Cannabis Use: Whole-Blood and Plasma Free and Glucuronidated Cannabinoid Pharmacokinetics following Controlled Smoked Cannabis Administration  

PubMed Central

BACKGROUND ?9-Tetrahydrocannabinol (THC) is the most frequently observed illicit drug in investigations of accidents and driving under the influence of drugs. THC-glucuronide has been suggested as a marker of recent cannabis use, but there are no blood data following controlled THC administration to test this hypothesis. Furthermore, there are no studies directly examining whole-blood cannabinoid pharmacokinetics, although this matrix is often the only available specimen. METHODS Participants (9 men, 1 woman) resided on a closed research unit and smoked one 6.8% THC cannabis cigarette ad libitum. We quantified THC, 11-hydroxy-THC (11-OH-THC), 11-nor-9-carboxy-THC (THCCOOH), cannabidiol (CBD), cannabinol (CBN), THC-glucuronide and THCCOOH-glucuronide directly in whole blood and plasma by liquid chromatography/ tandem mass spectrometry within 24 h of collection to obviate stability issues. RESULTS Median whole blood (plasma) observed maximum concentrations (Cmax) were 50 (76), 6.4 (10), 41 (67), 1.3 (2.0), 2.4 (3.6), 89 (190), and 0.7 (1.4) ?g/L 0.25 h after starting smoking for THC, 11-OH-THC, THCCOOH, CBD, CBN, and THCCOOH-glucuronide, respectively, and 0.5 h for THC-glucuronide. At observed Cmax, whole-blood (plasma) detection rates were 60% (80%), 80% (90%), and 50% (80%) for CBD, CBN, and THC-glucuronide, respectively. CBD and CBN were not detectable after 1 h in either matrix (LOQ 1.0 ?g/L). CONCLUSIONS Human whole-blood cannabinoid data following cannabis smoking will assist whole blood and plasma cannabinoid interpretation, while furthering identification of recent cannabis intake.

Schwope, David M.; Karschner, Erin L.; Gorelick, David A.; Huestis, Marilyn A.

2013-01-01

319

Peanut variety response to postemergence applications of carfentrazone-ethyl and pyraflufen-ethyl  

Microsoft Academic Search

Field experiments were conducted in the south Texas and Texas High Plains area in 2005 and 2006 to evaluate peanut variety tolerance to carfentrazone-ethyl and pyraflufen-ethyl. Lactofen was used as the standard. Carfentrazone-ethyl at 0.03 and 0.04kgai\\/ha, pyraflufen-ethyl at 0.003 and 0.004kgai\\/ha, and lactofen at 0.22kgai\\/ha were applied 35 days after planting (DAP) in south Texas and 51–56 DAP in

W. James Grichar; Peter A. Dotray; T. A. Baughman

2010-01-01

320

Antimicrobial and demelanizing activity of Ganoderma lucidum extract, p-hydroxybenzoic and cinnamic acids and their synthetic acetylated glucuronide methyl esters.  

PubMed

Mushroom extracts or isolated compounds may be useful in the search of new potent antimicrobial agents. Herein, it is described the synthesis of protected (acetylated) glucuronide derivatives of p-hydroxybenzoic and cinnamic acids, two compounds identified in the medicinal mushroom Ganoderma lucidum. Their antimicrobial and demelanizing activities were evaluated and compared to the parent acids and G. lucidum extract. p-Hydroxybenzoic and cinnamic acids, as also their protected glucuronide derivatives revealed high antimicrobial (antibacterial and antifungal) activity, even better than the one showed by commercial standards. Despite the variation in the order of parent acids and the protected glucuronide derivatives, their antimicrobial activity was always higher than the one revealed by the extract. Nevertheless, the extract was the only one with demelanizing activity against Aspergillus niger. The acetylated glucuronide derivatives could be deprotected to obtain glucuronide metabolites, which circulate in the human organism as products of the metabolism of the parent compounds. PMID:23607932

Heleno, Sandrina A; Ferreira, Isabel C F R; Esteves, Ana P; ?iri?, Ana; Glamo?lija, Jasmina; Martins, Anabela; Sokovi?, Marina; Queiroz, Maria João R P

2013-04-19

321

Preparation, characterisation and gas transport properties of trifluoroacetylated ethyl cellulose  

Microsoft Academic Search

A mixed ester of ethyl cellulose (EC) has been prepared by reaction of trifluoroacetic anhydride with the residual hydroxy groups of ethyl cellulose. The mixed ester is soluble in tetrahydrofuran, dichloromethane, chloroform, benzene and pyridine. FTIR and NMR spectra show that hydroxy groups of ethyl cellulose were replaced by trifluoroacetoxy groups. The trifluoroacetyl ethyl cellulose (TFAEC) has higher selectivity for

Yang Wang; Allan J Easteal

1999-01-01

322

Integrated HPLC-MS and (1)H-NMR spectroscopic studies on acyl migration reaction kinetics of model drug ester glucuronides.  

PubMed

Acyl glucuronides (AGs) are common, chemically reactive metabolites of acidic xenobiotics. Concerns about the potential of this class of conjugate to cause toxicity in man require efficient methods for the determination of reactivity, and this is commonly done by measuring transacylation kinetics. High-performance liquid chromatography-mass spectrometry (HPLC-MS) and nuclear magnetic resonance (NMR) spectroscopy were applied to the kinetic analysis of AG isomerization and hydrolysis for the 1-beta-O-AGs of ibufenac, (R)- and (S)-ibuprofen, and an alpha,alpha-dimethylated ibuprofen analogue. Each AG was incubated in either aqueous buffer at pH 7.4 or human plasma at 37 degrees C. Aliquots of these samples, taken throughout the reaction time course, were analysed by HPLC-MS and (1)H-NMR spectroscopy and the results compared. For identification of the AGs incubated in pH 7.4 buffer and for analysis of kinetic rates, (1)H-NMR spectroscopy generally gave the most complete set of data, but for human plasma the use of (1)H-NMR spectroscopy was impractical and HPLC-MS was more suitable. HPLC-MS was more sensitive than (1)H-NMR spectroscopy, but the lack of suitable stable-isotope labelled internal standards, together with differences in response between glucuronides and aglycones, made quantification problematic. Using HPLC-MS a specific 1-beta-O-AG-related ion at m/z 193 (the glucuronate fragment) was noted enabling selective determination of these isomers. In buffer, transacylation reactions predominated, with relatively little hydrolysis to the free aglycone observed. In human plasma incubations the observed rates of reaction were much faster than for buffer, and hydrolysis to the free aglycone was the major route. These results illustrate the strengths and weaknesses of each analytical approach for this class of analyte. PMID:19919325

Johnson, C H; Karlsson, E; Sarda, S; Iddon, L; Iqbal, M; Meng, X; Harding, J R; Stachulski, A V; Nicholson, J K; Wilson, I D; Lindon, J C

2010-01-01

323

CM2 antigen, a potential novel molecule participating in glucuronide transport on rat hepatocyte canalicular membrane  

PubMed Central

The polarized molecules predominately distributing at hepatocyte canalicular surface play a vital role in disclosing the process of bile formation and etiopathogenisis of cholestatic live diseases. Therefore, it is important to find novel polarized molecules on hepatocyte canalicular membrane. In the present study, canalicular membrane vesicles (CMVs) isolated from rat hepatocyte by density gradient centrifugation were used as immunogens to produce hybridoma and 46 strains of monoclonal antibodies (mAb) against CMVs were obtained. With a series of morphological assay methods, including immunohistochemistry, immunofluorescence and immuno-electron microscope, the antigens recognized by canalicular mAb1 (CM1) and canalicular mAb2 (CM2) were confirmed to predominately distribute at hepatocyte canalicular membrane. Transport activity assay revealed that CM2 could inhibit ATP-dependent E217?G uptake of rat hepatocyte CMVs. Meanwhile, Western blotting analysis showed that the molecular mass of CM2 antigen was approximately 110kDa, which was much less than Mr 180kDa of multidrug resistance-associated protein 2 (MRP2) involved in glucuronide transport. These data indicated that CM2 antigen might be a potential novel molecule participating in glucuronide transport on the hepatocyte canalicular membrane.

Wang, L.; Wang, J.; Zhou, X.; Li, J.; Shi, Y.; Han, Z.; Wang, X.; Li, S.; Yang, Z.; Wang, R.; Fan, D.; Han, Y.

2012-01-01

324

Nuclear receptors and endobiotics glucuronidation: the good, the bad, and the UGT.  

PubMed

The recent progresses in molecular biology and pharmacology approaches allowed the characterization of a series of nuclear receptors (NRs) as efficient regulators of uridine diphosphate glucuronosyltransferase (UGT) genes activity. These regulatory processes ensure an optimized UGT expression in response to specific endo- and/or exogenous stimuli. Many of these NRs are activated by endobiotics that also are substrates for UGTs. Thus, by activating their receptors, these endogenous substances control their own conjugation, leading to the concept that glucuronidation is an important part of feed-forward/feedback mechanisms by which bioactive molecules control their own concentrations. On the other hand, numerous studies have established the pharmacological relevance of NR-UGT regulatory pathways in the response to therapeutic ligands. The present review article aims at providing a comprehensive view of the physiological and pharmacological importance of the NR regulation of the expression and activity of endobiotics-conjugating UGT enzymes. Selected examples will illustrate how the organism profits from the feed-forward/feedback mechanisms involving NR-UGT pathways, but also how such regulatory processes are involved in the initiation and/or progression of several pathological situations. Finally, we will discuss how the present pharmacopeia involves NR-dependent regulation of endobiotics glucuronidation, and whether the unexploited NR-UGT axes could serve as pharmacological targets for novel therapeutics to restore endobiotics homeostasis. PMID:23330540

Bigo, Cyril; Caron, Sarah; Dallaire-Théroux, Amélie; Barbier, Olivier

2013-02-01

325

Microwave rotational spectrum and internal rotation in gauche ethyl alcohol  

Microsoft Academic Search

The microwave torsional–rotational spectra of several species of gauche ethyl alcohol have been assigned and analyzed. The species studied are CH3CH2OH, CH3CH2OD, CH2DCH2OH, and CH2DCH2OD, both methyl symmetric and asymmetric forms of the last two species. Rotational coefficients have been determined for all species. For the normal species, the components of the dipole moment have been determined as ‖?a‖=1.264±0.010 D,

Ramesh K. Kakar; C. Richard Quade

1980-01-01

326

Purification of ethyl docosahexaenoate by selective alcoholysis of fatty acid ethyl esters with immobilized Rhizomucor miehei lipase  

Microsoft Academic Search

Ethyl docosahexaenoate (E-DHA) is efficiently enriched by the selective alcoholysis of ethyl esters originating from tuna\\u000a oil with lauryl alcohol using immobilized lipase. Alcoholysis of ethyl esters by immobilized Rhizopus delemar lipase raised the E-DHA content in the unreacted ethyl ester fraction from 23 to 49 mol% in 90% yield. However, the content\\u000a of ethyl eicosapentaenoate (E-EPA) was higher than

Yuji Shimada; Kazuaki Maruyama; Akio Sugihara; Takashi Baba; Sadao Komemushi; Shigeru Moriyama; Yoshio Tominaga

1998-01-01

327

Associations between polymorphisms in glucuronidation and sulfation enzymes and sex steroid concentrations in premenopausal women in the United States  

Microsoft Academic Search

Glucuronidation, catalyzed by UDP-glucuronosyltransferases (UGT) and sulfation, catalyzed by sulfotransferases (SULT), are pathways through which sex steroids are metabolized to less active compounds. These enzymes are highly polymorphic and genetic variants frequently result in higher or lower activity. The phenotypic effects of these polymorphisms on circulating sex steroids in premenopausal women have not yet been investigated. One hundred and seventy

Mellissa Yong; Stephen M. Schwartz; Charlotte Atkinson; Karen W. Makar; Sushma S. Thomas; Frank Z. Stanczyk; Kim C. Westerlind; Katherine M. Newton; Victoria L. Holt; Wendy M. Leisenring; Johanna W. Lampe

2011-01-01

328

Human and Rat ABC Transporter Efflux of Bisphenol A and Bisphenol A Glucuronide: Interspecies Comparison and Implications for Pharmacokinetic Assessment  

EPA Science Inventory

Significant interspecies differences exist between human and rodent with respect to absorption, distribution, and excretion of bisphenol A (BPA) and its primary metabolite, BPA-glucuronide (BPA-G). ATP-Binding Cassette (ABC) transporter enzymes play important roles in these physi...

329

Identification of glucuronide metabolites of T-2 toxin and diacetoxyscirpenol in the bile of isolated perfused rat liver.  

PubMed

Isolated rat livers were perfused with either 2 mg T-2 toxin or diacetoxyscirpenol (DAS) in a recirculating perfusion system. To identify glucuronide conjugates, equal amounts of bile samples were incubated with and without (control) a beta-glucuronidase preparation and analyzed by capillary gas liquid chromatography-chemical ionization mass spectrometry. Enzyme treatment of bile obtained from liver perfused with T-2 toxin resulted in the detection of a total of 954 micrograms HT-2 toxin (control 6 micrograms), demonstrating that excretion into the bile was mainly as glucuronide conjugates. Minor metabolites of T-2 toxin in bile were identified as 3'-hydroxy HT-2 toxin (TC-3), 3'-hydroxy-7-hydroxy HT-2 toxin (TC-6), and the glucuronide form of T-2 triol (trace amount). The glucuronide conjugates of monoacetoxyscirpenol (340 micrograms) and scirpenetriol (10 micrograms) were found in bile obtained from liver perfused with DAS, while nonconjugated metabolites were not detected. It is assumed that considerable amounts of T-2 toxin and DAS were metabolized biphasically. In phase I both trichothecenes were deacetylated, in phase II the metabolites were conjugated giving rise to the glucuronic acid adducts. PMID:3715863

Gareis, M; Hashem, A; Bauer, J; Gedek, B

1986-06-15

330

Proteins identified as targets of the acyl glucuronide metabolite of mycophenolic acid in kidney tissue from mycophenolate mofetil treated rats  

Microsoft Academic Search

Covalent binding of the acyl glucuronide (AcMPAG) metabolite of the immunosuppressant mycophenolic acid (MPA) to proteins is considered a possible initiating event for organ toxicity. Since the kidney is involved in the formation and excretion of AcMPAG, it can be hypothesized that this tissue may be exposed to relatively high concentrations of this metabolite and would, therefore, be a particularly

Abdul R. Asif; Victor W. Armstrong; Antje Voland; Eberhard Wieland; Michael Oellerich; Maria Shipkova

2007-01-01

331

Urinary excretion of N-OH-2-amino-3-methylimidazo[4,5-f]quinoline-N-glucuronide in F344 rats is enhanced by green tea.  

PubMed

The effects of green tea on the metabolism of the food carcinogen 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) with emphasis on the formation of the detoxified glucuronides was studied. Two groups of 20 adult male and female Fischer 344 rats consumed 2% green tea or water for 6 weeks before being administered a single dose of 40 mg/kg body weight of [2-14C]IQ by oral gavage. Major metabolites in 24 h urine samples were separated by high-performance liquid chromatography (HPLC), including N-OH-IQ-N-glucuronide, 5-OH-IQ glucuronide and sulfate, IQ sulfamate and IQ itself. The structures of the main metabolites were established by mobility on the HPLC and by mass spectrometry. Sulfate esters and sulfamate were hydrolyzed by 0.1 N HCl for 15 min at 100 degrees C, yielding 5-OH-IQ and high levels of IQ. HPLC of the resulting product showed the N-OH-IQ-N-glucuronide and the 5-OH-IQ glucuronide, as well as IQ. The male and female rats drinking tea displayed a significantly higher (P < 0.05) excretion of the two major glucuronides. We conclude that intake of green tea increases the excretion of N-OH-IQ-N-glucuronide, a detoxified metabolite of the proximate carcinogen N-OH-IQ. PMID:11408354

Embola, C W; Weisburger, J H; Weisburger, M C

2001-07-01

332

Ethyl chloride improves antiseptic effect of betadine skin preparation for office procedures.  

PubMed

To determine if ethyl chloride is an effective disinfectant alone or combined with povidone iodine in a clinical setting, 35 volunteers had different portions of their knees swabbed with sterile cotton-tip applicators after an area of skin was prepared with either ethyl chloride alone, povidone iodine alone, or povidone iodine followed by ethyl chloride. An area with no preparation at all served as the control. Specimens were then cultured on agar plates and bacterial growth assessed. When the data was categorized as colony forming units (CFUs) or no CFUs, both ethyl chloride and povidone iodine used alone had significantly fewer specimens with CFUs (p=0.001) than controls, but were not significantly different from each other (p=0.18). Additionally, the combination of povidone iodine followed by ethyl chloride spray had significantly fewer samples with CFUs than either product used alone (p=0.001). In addition to its local anesthetic properties, ethyl chloride may be an effective disinfectant alone and may improve skin disinfection when used with povidone iodine compared to povidone iodine alone. PMID:22995356

Azar, Frederick M; Lake, Jason E; Grace, Sean P; Perkinson, Brian

2012-01-01

333

Effect of UDP-glucuronosyltransferase 2B15 polymorphism on bisphenol A glucuronidation.  

PubMed

Bisphenol A (BPA) is one of a number of potential endocrine-disrupting chemicals, which are metabolized mainly by UDP-glucuronosyltransferase 2B15 (UGT2B15) in humans. Six UGT2B15 allelic variants (UGT2B15*2, UGT2B15*3, UGT2B15*4, UGT2B15*5, UGT2B15*6, and UGT2B15*7; wild-type, UGT2B15*1) with amino acid substitutions have been found in Caucasian, African-American, Hispanic, and Oriental populations to date. In this study, the effects of amino acid substitutions in UGT2B15 on BPA glucuronidation were studied using recombinant UGT2B15 enzymes of wild-type (UGT2B15.1) and all identified variants (UGT2B15.2, UGT2B15.3, UGT2B15.4, UGT2B15.5, UGT2B15.6, and UGT2B15.7) expressed in insect (Sf9) cells. The K (m), V (max), and CL (int) values of UGT2B15.1 for BPA glucuronidation were 3.9 ?M, 650 pmol/min/mg protein, and 170 ?L/min/mg protein, respectively. Although there is no significant difference in the K (m) value between wild-type and any variant UGT2B15, the V (max) and CL (int) values of UGT2B15 variants having D85Y substitution were markedly reduced to 14 and 10% for UGT2B15.2, and 4.3 and 3.9% for UGT2B15.5 compared with those of UGT2B15.1, respectively. However, the K (m), V (max), and CL (int) values of UGT2B15.3, UGT2B15.4, UGT2B15.6, and UGT2B15.7 having L86S, T352I, and/or K523T substitution(s) for BPA glucuronidation were comparable to those of UGT2B15.1. These findings suggest that D85Y substitution in UGT2B15 decreases enzymatic function and that the polymorphic alleles of UGT2B15 are closely associated with variations in the metabolism and toxicity of BPA. The information gained in this study should help with in vivo extrapolation to assess the toxicity of endocrine-disrupting chemicals. PMID:21404072

Hanioka, Nobumitsu; Oka, Hiroyuki; Nagaoka, Kenjiro; Ikushiro, Shinichi; Narimatsu, Shizuo

2011-03-15

334

Rapid deconjugation of SN-38 glucuronide and adsorption of released free SN-38 by intestinal microorganisms in rat  

PubMed Central

One of the dose-limiting toxicities of irinotecan hydrochloride (CPT-11) is delayed-onset diarrhea. CPT-11 is converted to its active metabolite, SN-38, which is conjugated to SN-38 glucuronide (SN-38G). SN-38G excreted in the intestinal lumen is extensively deconjugated by bacterial ?-glucuronidase, resulting in the regeneration of SN-38, which causes diarrhea. However, the deconjugation of SN-38G by the intestinal microflora remains to be clarified. This study aimed to investigate the microbial transformation of SN-38G by an anaerobic mixed culture of rat cecal microorganisms. Concentrations of SN-38G and SN-38 were then determined using high-performance liquid chromatography. Complete deconjugation of SN-38G to SN-38 in the mixed cultures was observed within 1 h of incubation, with 62.7% of the added SN-38G being found in the supernatant. Approximately 80.4% of the SN-38 in the supernatant was bound to protein, and the remaining 19.6% was detected as active free SN-38. In total, only 12.3% (19.6 × 62.7%) of the SN-38G added to the test tube was found in the supernatant in the ultrafiltrable free form, indicating that approximately 90% of the SN-38G added to the growth medium either remained adsorbed onto the pelleted fraction or occurred in a protein-bound form in the supernatant. The remaining 10% of the SN-38G added to the growth medium existed in the unbound form, the form capable of causing damage to the intestinal membrane. In conclusion, these results indicated that the greater part of the SN-38 produced from SN-38G by the action of bacterial ?-glucuronidase is rapidly adsorbed onto intestinal bacterial cell walls or dietary fibers in pelleted fraction, and only 10% remains in the ultrafiltrable unbound form in the intestinal luminal fluid.

TAKAKURA, AKIRA; KURITA, AKINOBU; ASAHARA, TAKASHI; YOKOBA, MASANORI; YAMAMOTO, MICHIKO; RYUGE, SHINICHIRO; IGAWA, SATOSHI; YASUZAWA, YUKITOSHI; SASAKI, JIICHIRO; KOBAYASHI, HIROSUKE; MASUDA, NORIYUKI

2011-01-01

335

Usefulness of early morning urine estrone-3-glucuronide assay in the monitoring ovarian secretory function in precocious puberty.  

PubMed

To evaluate the usefulness of the urinary estrone-3-glucuronide (EI-3-G) in the monitoring of the ovarian function in girls, we studied 11 girls with idiopathic central precocious puberty (ICPP) treated with LHRH analogs (LHRHa) for 2-5 years. Plasma LH, FSH, 17-beta-Estradiol (E2) levels, early morning urine (EMU) E1-3-G concentrations, were assessed before and 3, 6, 12 months after the onset of treatment. As expected, mean basal plasma LH, FSH and E2 concentrations, as well as mean basal EMU E1-3-G levels were significantly (p < 0.01) higher in patients studied than in normal, age matched, prepubertal controls. Three out of the 11 sexually advanced girls showed undetectable (< 15 pg/ml) basal plasma E2 values. On the contrary, in each patient studied, individual basal E1-3-G levels were higher than in normal age-matched prepubertal girls. LHRHa treatment significantly suppressed both basal and peak stimulated plasma gonadotropins, plasma E2 and EMU E1-3-G. However, while serum E2 levels were below the assay detection limit, not allowing to assess the degree of gonadal suppression, E1-3-G urinary concentrations were detectable in each subject treated, in the range of the normal prepubertal values. EMU E1-3-G determination seems to be a very sensitive and reliable approach to the monitoring of the effectiveness of LHRHa treatment in sexually advanced girls, allowing to detect very low estrogen concentrations and to achieve the desired ovarian suppression. PMID:7629394

Bassi, F; Bartolini, O; Neri, A S; Gheri, R G; Magini, A; Bucciantini, S; Bruni, V

1995-02-01

336

Mouse hepatoma cell lines differing in aryl hydrocarbon receptor-mediated signaling have different activities for glucuronidation.  

PubMed

For studies on the aryl hydrocarbon receptor (AhR)-dependent toxicity of the mycotoxins alternariol (AOH) and alternariol methyl ether (AME), three mouse hepatoma (Hepa-1) cell lines with intact and with compromised AhR signaling were compared with respect to their activities for hydroxylation, methylation, and glucuronidation. Whereas the activities of cytochrome P450-mediated monooxygenase and catechol-O-methyl transferase were very low and did not differ between the three cell lines, a pronounced difference was observed for UDP-glucuronosyl transferase activity, which was much higher in Hepa-1c1c4 than in c1c7 and c1c12 cells. In all three cell types, the rate of glucuronidation of AOH was about four times higher than that of AME. Whereas AME caused a concentration-dependent G2/M arrest in each cell line, AOH arrested Hepa-1c1c7 and c1c12 cells but not c1c4 cells. However, Hepa-1c1c4 cells were arrested by AOH when ?-glucuronidase was added to the incubation medium in order to reverse the formation of AOH glucuronides. We conclude that the failure of AOH to cause cell cycle inhibition in Hepa-1c1c4 cells is due to its efficient glucuronidation. The considerable UDP-glucuronosyl transferase activity of Hepa-1c1c4 cells should be taken into account when other compounds are studied in this cell line. Moreover, we demonstrate that differences in glucuronide formation between cell types can be overcome by the addition of ?-glucuronidase to the cell culture medium. PMID:22143556

Burkhardt, B; Jung, S A; Pfeiffer, E; Weiss, C; Metzler, M

2011-12-06

337

Analysis of R- and S-hydroxywarfarin glucuronidation catalyzed by human liver microsomes and recombinant UDP-glucuronosyltransferases.  

PubMed

Coumadin (R-, S-warfarin) is a challenging drug to accurately dose, both initially and for maintenance, because of its narrow therapeutic range and wide interpatient variability and is typically administered as a racemic (Rac) mixture, which complicates the biotransformation pathways. The goal of the current work was to identify the human UDP-glucuronosyltransferases (UGTs) involved in the glucuronidation of the separated R- and S-enantiomers of 6-, 7-, and 8-hydroxywarfarin and the possible interactions between these enantiomers. The kinetic and inhibition constants for human recombinant 1A family UGTs toward these separated enantiomers have been assessed using high-performance liquid chromatography (HPLC)-UV-visible analysis, and product confirmations have been made using HPLC-mass spectrometry/mass spectrometry. We found that separated R- and S-enantiomers of 6-, 7-, and 8-hydroxywarfarin demonstrate significantly different glucuronidation kinetics and can be mutually inhibitory. In some cases significant substrate inhibition was observed, as shown by K(m), V(max), and K(i), comparisons. In particular, UGT1A1 and extrahepatic UGT1A10 have significantly higher capacities than other isoforms for S-7-hydroxywarfarin and R-7-hydroxywarfarin glucuronidation, respectively. Activity data generated using a set of well characterized human liver microsomes supported the recombinant enzyme data, suggesting an important (although not exclusive) role for UGT1A1 in glucuronidation of the main warfarin metabolites, including Rac-6- and 7-hydroxywarfarin and their R- and S-enantiomers in the liver. This is the first demonstration that the R- and S-enantiomers of hydroxywarfarins are glucuronidated, with significantly different enzymatic affinity and capacity, and supports the importance of UGT1A1 as the major hepatic isoform involved. PMID:21972237

Bratton, Stacie M; Mosher, Carrie M; Khallouki, Farid; Finel, Moshe; Court, Michael H; Moran, Jeffery H; Radominska-Pandya, Anna

2011-10-04

338

Analysis of R- and S-Hydroxywarfarin Glucuronidation Catalyzed by Human Liver Microsomes and Recombinant UDP-Glucuronosyltransferases  

PubMed Central

Coumadin (R-, S-warfarin) is a challenging drug to accurately dose, both initially and for maintenance, because of its narrow therapeutic range and wide interpatient variability and is typically administered as a racemic (Rac) mixture, which complicates the biotransformation pathways. The goal of the current work was to identify the human UDP-glucuronosyltransferases (UGTs) involved in the glucuronidation of the separated R- and S-enantiomers of 6-, 7-, and 8-hydroxywarfarin and the possible interactions between these enantiomers. The kinetic and inhibition constants for human recombinant 1A family UGTs toward these separated enantiomers have been assessed using high-performance liquid chromatography (HPLC)-UV-visible analysis, and product confirmations have been made using HPLC-mass spectrometry/mass spectrometry. We found that separated R- and S-enantiomers of 6-, 7-, and 8-hydroxywarfarin demonstrate significantly different glucuronidation kinetics and can be mutually inhibitory. In some cases significant substrate inhibition was observed, as shown by Km, Vmax, and Ki, comparisons. In particular, UGT1A1 and extrahepatic UGT1A10 have significantly higher capacities than other isoforms for S-7-hydroxywarfarin and R-7-hydroxywarfarin glucuronidation, respectively. Activity data generated using a set of well characterized human liver microsomes supported the recombinant enzyme data, suggesting an important (although not exclusive) role for UGT1A1 in glucuronidation of the main warfarin metabolites, including Rac-6- and 7-hydroxywarfarin and their R- and S-enantiomers in the liver. This is the first demonstration that the R- and S-enantiomers of hydroxywarfarins are glucuronidated, with significantly different enzymatic affinity and capacity, and supports the importance of UGT1A1 as the major hepatic isoform involved.

Bratton, Stacie M.; Mosher, Carrie M.; Khallouki, Farid; Finel, Moshe; Court, Michael H.; Moran, Jeffery H.

2012-01-01

339

A recombinant phenobarbital-inducible rat liver UDP-glucuronosyltransferase (UDP-glucuronosyltransferase 2B1) stably expressed in V79 cells catalyzes the glucuronidation of morphine, phenols, and carboxylic acids.  

PubMed

V79 (Chinese hamster lung fibroblast) cell lines expressing a functional recombinant phenobarbital-inducible rat liver UDP-glucuronosyltransferase (UGT), i.e., UGT2B1, were established. Western blot analysis of positive colonies, using anti-rat liver UGT antibodies, revealed the presence of an immunoreactive polypeptide of the expected molecular mass of 52 kDa. The substrate specificity of the recombinant enzyme toward > 100 compounds was determined. Phenolic and alcoholic substrates included 4-methylumbelliferone, 4-hydroxybiphenyl, chloramphenicol, and testosterone, but a range of carboxylic acids of both endogenous (medium-chain saturated fatty acids, long-chain polyunsaturated fatty acids, and bile acids) and exogenous (profen nonsteroidal anti-inflammatory drugs, fibrate hypolipidemic agents, and sodium valproate) origin were also accepted, indicating that the enzyme was capable of forming both ether- and ester-type glucuronides from various structurally unrelated compounds. Determination of apparent kinetic constants for the glucuronidation by UGT2B1 of selected aglycones revealed a high maximal velocity toward the 3-position of morphine (49.3 +/- 2.2 nmol/min/mg of protein), compared with other known substrates such as 4-methylumbelliferone (2.67 +/- 0.11 nmol/min/mg of protein) or clofibric acid (0.06 +/- 0.02 nmol/min/mg of protein). To gain a better insight into the mechanisms underlying the apparently wide substrate specificity of UGT2B1, series of structurally related compounds were tested as potential substrates. The rate of glucuronidation of unbranched saturated fatty acids and omega,omega,omega-triphenylalkanoic acids increased progressively with increasing alkyl chain length and then declined, with the best substrates in these two homologous series being decanoic acid and 4,4,4-triphenylbutanoic acid, respectively. Glucuronidation of para-substituted phenols always proceeded at a higher rate than that of the corresponding para-substituted benzoic acids. This could mean that the aglycon hydroxyl group was better positioned in the enzyme active site in the case of phenols. Alternatively, if the initial interaction with the enzyme required the aglycon to be in the protonated uncharged form, then the observation could be explained by the difference in ionization between phenols and benzoic acids at the incubation pH used. The introduction of a bulky alkyl group into the para-position led to increases of up to 300-fold in the rate of glucuronidation, probably as a result of the increased aglycon lipophilicity. Finally, the enzyme showed a degree of stereo- and regiospecificity, preferring (S)-ibuprofen to the R-enantiomer (Vmax/Km, 3.06 and 1.10 microliters/min/mg of protein, respectively) and glucuronidating lithocholic acid but not hyodeoxycholic acid, which differs by only a single hydroxyl group.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8302279

Pritchard, M; Fournel-Gigleux, S; Siest, G; Mackenzie, P; Magdalou, J

1994-01-01

340

Use of positive ion fast atom bombardment mass spectrometry for rapid identification of a bile alcohol glucuronide isolated from cerebrotendinous xanthomatosis patients  

SciTech Connect

The identification of a major biliary and plasma bile alcohol glucuronide, 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 25-tetrol-3-0-beta-D-glucuronide, present in cerebrotendinous xanthomatosis (CTX) patients, was investigated by positive ion fast atom bombardment mass spectrometry (FAB-MS). The spectrum was characterized by abundant ions formed by attachment of a proton, (M + H)+, or of alkali ions, (M + Na)+ and (M + 39K)+, to the glucuronide salt. These ions allowed an unambiguous deduction of the molecular weight of the sample. It is suggested that FAB-MS could be used in the rapid diagnosis of CTX.

Dayal, B.; Salen, G.; Tint, G.S.; Shefer, S.; Benz, S.W. (UMDNJ-New Jersey Medical School, Newark (USA))

1990-02-01

341

Determination of UDP-glucuronosyltransferase UGT1A6 activity in human and rat liver microsomes by HPLC with UV detection  

Microsoft Academic Search

A simple and sensitive method for the determination of UDP-glucuronosyltransferase UGT1A6 activity using 4-methylumbelliferone (4-MU) and 4-nitrophenol (4-NP) as substrates in human and rat liver microsomes by high-performance liquid chromatography (HPLC) with uv detection is reported. The method was validated for the determination of 4-methylumbelliferyl ?-d-glucuronide (4-MUG) and 4-nitrophenyl ?-d-glucuronide (4-NPG) with respect to specificity, linearity, detection limit, recovery, stability,

Nobumitsu Hanioka; Hideto Jinno; Toshiko Tanaka-Kagawa; Tetsuji Nishimura; Masanori Ando

2001-01-01

342

Uremic toxins inhibit renal metabolic capacity through interference with glucuronidation and mitochondrial respiration.  

PubMed

During chronic kidney disease (CKD), drug metabolism is affected leading to changes in drug disposition. Furthermore, there is a progressive accumulation of uremic retention solutes due to impaired renal clearance. Here, we investigated whether uremic toxins can influence the metabolic functionality of human conditionally immortalized renal proximal tubule epithelial cells (ciPTEC) with the focus on UDP-glucuronosyltransferases (UGTs) and mitochondrial activity. Our results showed that ciPTEC express a wide variety of metabolic enzymes, including UGTs. These enzymes were functionally active as demonstrated by the glucuronidation of 7-hydroxycoumarin (7-OHC; K(m) of 12±2?M and a V(max) of 76±3pmol/min/mg) and p-cresol (K(m) of 33±13?M and a V(max) of 266±25pmol/min/mg). Furthermore, a wide variety of uremic toxins, including indole-3-acetic acid, indoxyl sulfate, phenylacetic acid and kynurenic acid, reduced 7-OHC glucuronidation with more than 30% as compared with controls (p<0.05), whereas UGT1A and UGT2B protein expressions remained unaltered. In addition, our results showed that several uremic toxins inhibited mitochondrial succinate dehydrogenase (i.e. complex II) activity with more than 20% as compared with controls (p<0.05). Moreover, indole-3-acetic acid decreased the reserve capacity of the electron transport system with 18% (p<0.03). In conclusion, this study shows that multiple uremic toxins inhibit UGT activity and mitochondrial activity in ciPTEC, thereby affecting the metabolic capacity of the kidney during CKD. This may have a significant impact on drug and uremic retention solute disposition in CKD patients. PMID:23017367

Mutsaers, H A M; Wilmer, M J G; Reijnders, D; Jansen, J; van den Broek, P H H; Forkink, M; Schepers, E; Glorieux, G; Vanholder, R; van den Heuvel, L P; Hoenderop, J G; Masereeuw, R

2012-09-24

343

Skin of the male African catfish, Clarias gariepinus: a source of steroid glucuronides  

SciTech Connect

Steroid metabolism in the skin of mature male African catfish, Clarias gariepinus, reared in the laboratory, was studied in vitro by tissue incubations with (/sup 3/H)pregnenolone, (/sup 3/H)dehydroepiandrosterone, (/sup 3/H)17 alpha-hydroxyprogesterone, (/sup 3/H)androstenedione, (/sup 14/C)11 beta-hydroxyandrostenedione, and (/sup 3/H)testosterone as precursors. While pregnenolone was not converted to any other steroid, dehydroepiandrosterone was transformed mainly to 5-androstene-3 beta, 17 beta-diol. The products of 17 alpha-hydroxyprogesterone incubations were 5 beta-pregnane-3 alpha,17 alpha-diol-20-one, 5 beta-pregnane-3 alpha,17 alpha, 20 beta-triol, and 5 beta-pregnan-17 alpha-o1-3,20-dione. The major steroids of androstenedione incubations were etiocholanolone, testosterone, and androsterone. Testosterone was converted mainly to etiocholanolone and androstenedione, and only small quantities of 11 beta-hydroxytestosterone, 11-ketotestosterone, and 11-ketoandrostenedione were the metabolites found in 11 beta-hydroxyandrostenedione incubation. These results demonstrated the presence of the enzymes 5 alpha- and 5 beta-reductases and 3 alpha-, 11 beta-, 17 beta-, and 20 beta-hydroxysteroid dehydrogenases in the skin. From enzymehistochemical results it appeared that the steroid conversions take place in the epithelial cells. Moreover, the presence of UDP-glucose dehydrogenase, an enzyme involved in the synthesis of glucuronic acid, in these cells indicates the possibility of steroid glucuronide formation. Indeed significant amounts of water-soluble steroid conjugates, particularly 5 beta-dihydrotestosterone- and testosterone-glucuronide, were found in the incubations with androstenedione and testosterone, indicating the presence of the UDP-glucuronosyl transferase in the catfish skin.

Ali, S.A.; Schoonen, W.G.; Lambert, J.G.; Van den Hurk, R.; Van Oordt, P.G.

1987-06-01

344

27 CFR 21.107 - Ethyl acetate.  

Code of Federal Regulations, 2013 CFR

...107 Ethyl acetate. (a) 85 percent ester: (1) Acidity (as acetic acid). Not more than 0.015 percent by weight...and none above 80 °C. (b) 100 percent ester: (1) Acidity (as acetic acid). Not more than 0.010 percent by...

2013-04-01

345

Elastic electron scattering by ethyl vinyl ether  

SciTech Connect

We report measured and calculated results for elastic scattering of low-energy electrons by ethyl vinyl ether (ethoxyethene), a prototype system for studying indirect dissociative attachment processes that may play a role in DNA damage. The integral cross section displays the expected {pi}{sup *} shape resonance. The agreement between the calculated and measured cross sections is generally good.

Khakoo, M. A.; Hong, L.; Kim, B.; Winstead, C.; McKoy, V. [Department of Physics, California State University, Fullerton, California 92834 (United States); Troy High School, 2200 Dorothy Lane, Fullerton, California 92831 (United States); A. A. Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125 (United States)

2010-02-15

346

40 CFR 180.441 - Quizalofop ethyl; tolerances for residues.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Quizalofop ethyl; tolerances for residues. ...Specific Tolerances § 180.441 Quizalofop ethyl; tolerances for residues. ...the combined residues of the herbicide quizalofop...

2010-07-01

347

40 CFR 180.441 - Quizalofop ethyl; tolerances for residues.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Quizalofop ethyl; tolerances for residues. ...Specific Tolerances § 180.441 Quizalofop ethyl; tolerances for residues. ...the combined residues of the herbicide quizalofop...

2009-07-01

348

21 CFR 172.872 - Methyl ethyl cellulose.  

Code of Federal Regulations, 2010 CFR

...Multipurpose Additives § 172.872 Methyl ethyl cellulose. The food additive methyl ethyl cellulose may be safely used in food in accordance...prescribed conditions. (a) The additive is a cellulose ether having the general formula [C6...

2009-04-01

349

21 CFR 172.872 - Methyl ethyl cellulose.  

Code of Federal Regulations, 2013 CFR

...Multipurpose Additives § 172.872 Methyl ethyl cellulose. The food additive methyl ethyl cellulose may be safely used in food in accordance...prescribed conditions. (a) The additive is a cellulose ether having the general formula [C6...

2013-04-01

350

21 CFR 172.872 - Methyl ethyl cellulose.  

Code of Federal Regulations, 2010 CFR

...Multipurpose Additives § 172.872 Methyl ethyl cellulose. The food additive methyl ethyl cellulose may be safely used in food in accordance...prescribed conditions. (a) The additive is a cellulose ether having the general formula [C6...

2010-01-01

351

Biosynthesis of ethyl caproate and other short ethyl esters catalyzed by cutinase in organic solvent  

Microsoft Academic Search

The main objective of this work was to study the enzymatic synthesis of short chain ethyl esters, a group of relevant aroma molecules, by Fusarium solani pisi cutinase in an organic solvent media (iso-octane), and to assess the influence of different parameters on the reaction yield.Cutinase displayed high initial esterification rates in iso-octane, which amounted to 1.15?molmin?1mg?1 for ethyl butyrate

Dragana P. C. de Barros; Luís P. Fonseca; P. Fernandes; Joaquim M. S. Cabral; Ljiljana Mojovic

2009-01-01

352

Antihyperglycemic effect of Hypericum perforatum ethyl acetate extract on streptozotocin-induced diabetic rats  

PubMed Central

Objective To evaluate the antihyperglycemic activity of ethyl acetate extract of Hypericum perforatum (H. perforatum) in streptozotocin (STZ)-induced diabetic rats. Methods Acute toxicity and oral glucose tolerance test were performed in normal rats. Male albino rats were rendered diabetic by STZ (40 mg/kg, intraperitoneally). H. perforatum ethyl acetate extract was orally administered to diabetic rats at 50, 100 and 200 mg/kg doses for 15 days to determine the antihyperglycemic activity. Biochemical parameters were determined at the end of the treatment. Results H. perforatum ethyl acetate extract showed dose dependant fall in fasting blood glucose (FBG). After 30 min of extract administration, FBG was reduced significantly when compared with normal rats. H. perforatum ethyl acetate extract produced significant reduction in plasma glucose level, serum total cholesterol, triglycerides, glucose-6-phosphatase levels. Tissue glycogen content, HDL-cholesterol, glucose-6-phosphate dehydrogenase were significantly increased compared with diabetic control. No death or lethal effect was observed in the toxic study. Conclusions The results demonstrate that H. perforatum ethyl acetate extract possesses potent antihyperglycemic activity in STZ induced diabetic rats.

Arokiyaraj, S; Balamurugan, R; Augustian, P

2011-01-01

353

Endogenous Steroid Metabolism Is Indicated by Fluctuations of Endogenous Steroid and Steroid Glucuronide Levels in Early Development of the Steelhead Trout ( Oncorhynchus mykiss)  

Microsoft Academic Search

Concentrations of endogenous steroids and their glucuronide conjugates fluctuated during early development in steelhead troutOncorhynchus mykiss.Whole body content of sex steroids and steroid glucuronides of both bisexual and gynogenetic (all female) steelhead trout were quantified by radioimmunoassay. Concentrations of 17?-estradiol (E2) and cortisol increased 2–4 days before hatch. Two days after hatch, 11-ketotestosterone (11KT) increased in concentrations in both gynogenetic

Choo-Guan Yeoh; Carl B. Schreck; Grant W. Feist; Martin S. Fitzpatrick

1996-01-01

354

Quantitation of the flavonoid wogonin and its major metabolite wogonin-7?- d-glucuronide in rat plasma by liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

This study described the application of liquid chromatography–tandem mass spectrometry for the quantitation of wogonin and its major metabolite in rat plasma. Only one conjugated metabolite with glucuronic acid was identified by chromatographic and electrospray multi-stage mass spectrometric assay. A derivatization reaction with 2-chlorethanol further demonstrated that the metabolite was wogonin-7?-d-glucuronide (W-7-G), not wogonin-5?-d-glucuronide. Other conjugated metabolites, e.g., sulfates and

Xiaoyan Chen; Hongyan Wang; Yue Du; Dafang Zhong

2002-01-01

355

Glucuronidation of dihydrotestosterone and trans-androsterone by recombinant UDP-glucuronosyltransferase (UGT) 1A4: evidence for multiple UGT1A4 aglycone binding sites.  

PubMed

UDP-glucuronosyltransferase (UGT) 1A4-catalyzed glucuronidation is an important drug elimination pathway. Although atypical kinetic profiles (nonhyperbolic, non-Michaelis-Menten) of UGT1A4-catalyzed glucuronidation have been reported occasionally, systematic kinetic studies to explore the existence of multiple aglycone binding sites in UGT1A4 have not been conducted. To this end, two positional isomers, dihydrotestosterone (DHT) and trans-androsterone (t-AND), were used as probe substrates, and their glucuronidation kinetics with HEK293-expressed UGT1A4 were evaluated both alone and in the presence of a UGT1A4 substrate [tamoxifen (TAM) or lamotrigine (LTG)]. Coincubation with TAM, a high-affinity UGT1A4 substrate, resulted in a concentration-dependent activation/inhibition effect on DHT and t-AND glucuronidation, whereas LTG, a low-affinity UGT1A4 substrate, noncompetitively inhibited both processes. The glucuronidation kinetics of TAM were then evaluated both alone and in the presence of different concentrations of DHT or t-AND. TAM displayed substrate inhibition kinetics, suggesting that TAM may have two binding sites in UGT1A4. However, the substrate inhibition kinetic profile of TAM became more hyperbolic as the DHT or t-AND concentration was increased. Various two-site kinetic models adequately explained the interactions between TAM and DHT or TAM and t-AND. In addition, the effect of TAM on LTG glucuronidation was evaluated. In contrast to the mixed effect of TAM on DHT and t-AND glucuronidation, TAM inhibited LTG glucuronidation. Our results suggest that multiple aglycone binding sites exist within UGT1A4, which may result in atypical kinetics (both homotropic and heterotropic) in a substrate-dependent fashion. PMID:20007295

Zhou, Jin; Tracy, Timothy S; Remmel, Rory P

2009-12-09

356

Synthesis, radiolabeling and In Vivo tissue distribution of an anti-oestrogen glucuronide compound, (99m)Tc-TOR-G.  

PubMed

Toremifene (TOR) has been used as an anti-oestrogen drug for the treatment and prevention of human breast cancer. The aim of this study was the addition of the hydrophilic groups diethylenetriamine pentaacetic acid (DTPA) and glucuronic acid to the starting substance TOR and to label it with technetium-99m ((99m)Tc) radionuclide and to investigate radiopharmaceutical potential of the new compound. The synthesis reactions are completed in four steps, including enzymatic reaction, with the following substeps; preparation of microsomal fraction from Hutu 80 cell line and subsequent purification of UDP-glucuronyl transferase (UDPGT), estimation of protein quantity in microsomal samples and glucuronidation reaction. The results indicate that (99m)Tc-TOR-G may be proposed as a new anti-oestrogen glucuronide imaging agent for ovarian tumours. PMID:20530435

Muftuler, F Z Biber; Unak, P; Yolcular, S; Kilcar, A Yurt; Ichedef, C; Enginar, H; Sakarya, S

2010-04-01

357

Morphine and morphine-glucuronide concentrations in plasma and CSF during long-term administration of oral morphine.  

PubMed Central

Concentrations of morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) were measured by h.p.l.c. in plasma and cerebrospinal fluid (CSF) samples from 16 patients with cancer receiving oral (controlled-release) morphine. There was a close correlation between plasma and CSF morphine concentrations (r = 0.94, P = 0.0001) and both correlated with drug dosage (r = 0.61, P = 0.013 and r = 0.74, P = 0.0001, respectively). M3G and M6G in plasma and CSF were correlated (r = 0.81 and r = 0.82, both P = 0.0001). No relationship was apparent between M plus M6G concentrations in the CSF and pain scores.

van Dongen, R T; Crul, B J; Koopman-Kimenai, P M; Vree, T B

1994-01-01

358

Identification of brain-targeted bioactive dietary quercetin-3-O-glucuronide as a novel intervention for Alzheimer's disease.  

PubMed

Epidemiological and preclinical studies indicate that polyphenol intake from moderate consumption of red wines may lower the relative risk for developing Alzheimer's disease (AD) dementia. There is limited information regarding the specific biological activities and cellular and molecular mechanisms by which wine polyphenolic components might modulate AD. We assessed accumulations of polyphenols in the rat brain following oral dosage with a Cabernet Sauvignon red wine and tested brain-targeted polyphenols for potential beneficial AD disease-modifying activities. We identified accumulations of select polyphenolic metabolites in the brain. We demonstrated that, in comparison to vehicle-control treatment, one of the brain-targeted polyphenol metabolites, quercetin-3-O-glucuronide, significantly reduced the generation of ?-amyloid (A?) peptides by primary neuron cultures generated from the Tg2576 AD mouse model. Another brain-targeted metabolite, malvidin-3-O-glucoside, had no detectable effect on A? generation. Moreover, in an in vitro analysis using the photo-induced cross-linking of unmodified proteins (PICUP) technique, we found that quercetin-3-O-glucuronide is also capable of interfering with the initial protein-protein interaction of A?(1-40) and A?(1-42) that is necessary for the formation of neurotoxic oligomeric A? species. Lastly, we found that quercetin-3-O-glucuronide treatment, compared to vehicle-control treatment, significantly improved AD-type deficits in hippocampal formation basal synaptic transmission and long-term potentiation, possibly through mechanisms involving the activation of the c-Jun N-terminal kinases and the mitogen-activated protein kinase signaling pathways. Brain-targeted quercetin-3-O-glucuronide may simultaneously modulate multiple independent AD disease-modifying mechanisms and, as such, may contribute to the benefits of dietary supplementation with red wines as an effective intervention for AD. PMID:23097297

Ho, Lap; Ferruzzi, Mario G; Janle, Elsa M; Wang, Jun; Gong, Bing; Chen, Tzu-Ying; Lobo, Jessica; Cooper, Bruce; Wu, Qing Li; Talcott, Stephen T; Percival, Susan S; Simon, James E; Pasinetti, Giulio Maria

2012-10-24

359

Liquid chromatographic-mass spectrometric analysis of glucuronide-conjugated anabolic steroid metabolites: method validation and interlaboratory comparison  

Microsoft Academic Search

Liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS\\/MS) method for simultaneous and direct detection of 12 glucuronide-conjugated anabolic androgenic steroid (AAS) metabolites in human urine is described. The compounds selected were the main metabolites detected in human urine after dosing of the most widely abused AAS in sports, e.g. methandienone, methenolone, methyltestosterone, nandrolone and testosterone, and certain deuterium-labeled analogs of

Laura Hintikka; Tiia Kuuranne; Antti Leinonen; Mario Thevis; W. Schanzer; John Halket; David Cowan; Joachim Grosse; Peter Hemmersbach; Michel W. F. Nielen; Risto Kostiainen

2008-01-01

360

Investigation of in vitro efficiency of magnetic nanoparticle-conjugated 125 I-uracil glucuronides in adenocarcinoma cells  

Microsoft Academic Search

Modification of the magnetic properties of a drug can be used to direct the drug to the desired site, enhancing its therapeutic\\u000a effectiveness and reducing side effects. In this study, surface-modified magnetic nanoparticles were immobilized with uracil\\u000a glucuronide derivatives and then labeled with I-125. The morphology, structure, and composition of the magnetic particles\\u000a were examined by TEM, SEM, VSM, and

E. Ilker Medine; Perihan Ünak; Serhan Sakarya; Feriha Özkaya

361

Enzymatic synthesis of 125\\/131I labeled 8-hydroxyquinoline glucuronide and in vitro\\/ in vivo evaluation of biological influence  

Microsoft Academic Search

8-Hydroxyquinoline (8-OHQ) is a long-known molecule which due to its metal-complexation ability is frequently used for analysis. It is also called oxine. Oxine and derivatives have been investigated to process antitumor and antimicrobial activities. 8-Hydroxyquinolyl-glucuronide (8-OHQ-Glu) was enzymatically synthesized using microsome preparates separated from Hutu-80 cells, labeled with 125I to perform a radionuclide labeled prodrug and investigated of its biological

Reyhan Ye?ila?aç; Perihan Ünak; E. ?lker Medine; Çi?dem A. ?çhedef; Turkan Ertay; F. Z. Biber Müftüler

2011-01-01

362

Production of ethyl alcohol from bananas  

SciTech Connect

The production of ethyl alcohol from waste bananas presents many special problems. During cooking, matting of the latex fibers from the banana peel recongeal when cooled and left untreated. This problem has been addressed by Alfaro by the use of CaC1/sub 2/. Separation of solids prior to distillation of the mashes in an economical fashion and use of the by product are also of concern to banana processors.

Jones, R.L.; Towns, T.

1983-12-01

363

Methyl ethyl ketone extraction of Tc species  

Microsoft Academic Search

Methyl ethyl ketone extraction of technetium species from aqueous solutions of neutron irradiated ammonium molybdate crystals was studied; the two species extracted were separated by high voltage paper electrophoresis. The one was the99mTcO\\u000a4\\u000a–\\u000a ion and the other, a99mTc non-charged immobile species, probably TcO2.aq, which concentrated at the point of application on the electrophoresis paper strip.

S. Bulbulian

1984-01-01

364

Ethyl pyruvate improves survival in awake hemorrhage  

Microsoft Academic Search

Classical experimental models of hemorrhage are characterized by the use of anesthetics that may interfere with the typical\\u000a immune responses and pathology of hemorrhage\\/resuscitation. Thus, therapeutic strategies successful in anesthetized animals\\u000a might not be beneficial in clinical trials. In this study, we analyzed whether ethyl pyruvate could provide therapeutic benefits\\u000a during resuscitation in awake (unanesthetized) hemorrhage. Our results indicate that

Bolin Cai; Michael Brunner; Haichao Wang; Ping Wang; Edwin A. Deitch; Luis Ulloa

2009-01-01

365

Effects of an external exposure to 200 ppm methyl ethyl ketone on nasal mucosa in healthy volunteers  

Microsoft Academic Search

Objectives: To investigate the effects of an acute exposure to 200 ppm methyl ethyl ketone on the nasal mucosa of healthy volunteers. Methods: Nineteen healthy non-smoking men were exposed to 200 ppm methyl ethyl ketone and to a sham exposure in an exposure chamber, using a cross-over design. Mucociliary transport time was determined with the saccharine test. Interleukin (IL)-1#, IL-6,

A. Muttray; D. Jung; L. Klimek; C. Kreiner

2002-01-01

366

Assessment of the toxicity of ethyl-parathion to earthworms ( Aporrectodea caliginosa) using behavioural, physiological and biochemical markers  

Microsoft Academic Search

The aim of this study was to determine the influence of soil properties on ethyl-parathion toxicity to earthworms (Aporrectodea caliginosa) using different markers (mortality, cholinesterase (ChE) activity, body mass change and burrowing behaviour). In a first experiment, the toxicity of five different concentrations of ethyl-parathion was studied in four different soils, three from Mexico and one from France, which were

Angeluz Olvera-Velona; Yvan Capowiez; Odile Mascle; Laura Ortiz-Hernandez; Pierre Benoit

2008-01-01

367

Dynamic changes in size distribution of emulsion droplets during ethyl acetate-based microencapsulation process.  

PubMed

This study investigated the dynamic effect of the emulsification process on emulsion droplet size in manufacturing microspheres using ethyl acetate as an organic solvent. A dispersed phase consisting of poly(lactide-co-glycolide) and ethyl acetate was emulsified in a poly(vinyl alcohol) aqueous solution for a predetermined time ranging from 2 to 9, 16, 23, 30, 40, 50, or 60 minutes. Ethyl acetate was then quickly extracted to transform emulsion droplets into solidified microspheres, and their size distribution was determined. This experimental design allowed quantification of the size distribution of emulsion droplets over the course of emulsification. When emulsification time was extended from 2 to 60 minutes, the emulsion droplets decreased in size from 98.1 to 50.3 microm and their surface area increased from 0.07 to 0.29 m2/g. Overall, prolonging emulsification time up to 60 minutes resulted in the progressive evolution of smaller emulsion droplets (1-60 microm) and the simultaneous disappearance of larger ones (> 81 microm). Increases in the total number of microspheres and their surface area were caused mainly by continuous fragmentation of emulsion droplets before ethyl acetate extraction. The increase in the smaller microsphere population might also be due in part to shrinkage of microspheres. These results show that the onset of ethyl acetate extraction influenced the kinetics of the breakup and formation of emulsion droplets, thereby affecting to a great extent the size distribution of microspheres. PMID:14727854

Bahl, Y; Sah, H

2000-03-23

368

Respiratory depression following morphine and morphine-6-glucuronide in normal subjects.  

PubMed Central

1. Morphine 6-glucuronide (M6G) is a metabolite of morphine with analgesic activity. A double-blind, randomised comparison of the effects of morphine and M6G on respiratory function was carried out in 10 normal subjects after i.v. morphine (10 mg 70 kg-1) or M6G (1, 3.3 and 5 mg 70 kg-1). Analgesic potency was also assessed using an ischaemic pain test and other toxic effects were monitored. 2. Following morphine there was a significant increase in arterial PCO2, as measured by blood gases 45 min post dose (0.54 +/- 0.24 (s.d.) kPa, P < 0.001), and in transcutaneous PCO2 from 15 min post dose until the end of the study period (4 h), whereas blood gas and transcutaneous PCO2 were unchanged after M6G at 1.0, 3.3 and 5.0 mg 70 kg-1. This increased PCO2 following morphine was associated with an increase in expired CO2 concentration (FECO2) (0.20 +/- 0.14% expired air at 15 min post dose, P = 0.002), compared with small but significant reductions in FECO2 following morphine 6-glucuronide (-0.15 +/- 0.17% at 1 mg 70 kg-1 P = 0.030, -0.14 +/- 0.15% at 3.3 mg 70 kg-1 P = 0.017, -0.18 +/- 0.11% at 5 mg 70 kg-1 P = 0.024). Maximum transcutaneous PCO2 was significantly increased after morphine (0.63 +/- 0.28 kPa P = 0.009), but was not changed after M6G at 1 mg (0.10 +/- 0.34 kPa P = 0.11) 3.3 mg (0.06 +/- 0.37 kPa P = 0.34) or 5 mg (0.26 +/- 0.07 kPa P = 0.10).(ABSTRACT TRUNCATED AT 250 WORDS)

Thompson, P I; Joel, S P; John, L; Wedzicha, J A; Maclean, M; Slevin, M L

1995-01-01

369

Health Hazard Evaluation/Toxicity Determination. Trantex Corporation, Springfield, Massachusetts.  

National Technical Information Service (NTIS)

The National Institute for Occupational Safety and Health (NIOSH), conducted a health hazard survey to evaluate exposure to solvent vapors at Trantex Corporation, Springfield, Massachusetts. It was determined that ethyl acetate, n-propyl alcohol, ethyl al...

L. B. Larsen

1974-01-01

370

Determination of a peroxisome proliferator-activated receptor ? agonist, 1-(trans-methylimino-N-oxy)-6-(2-morpholinoethoxy-3-phenyl-1H-indene-2-carboxylic acid ethyl ester (KR-62980) in rat plasma by liquid chromatography-tandem mass spectrometry.  

PubMed

A novel peroxisome proliferator-activated receptor ? (PPAR?) agonist, KR-62980, was determined by liquid-liquid extraction with ethyl acetate and liquid chromatography-tandem mass spectrometry (LC/MS/MS) in rat plasma. In order to evaluate the pharmacokinetics of KR-62980, a reliable, selective and sensitive high-performance liquid chromatographic method with electrospray ionization tandem mass spectrometry was developed for the quantification of KR-62980 in rat plasma. KR-62980 and imipramine (IS) were separated on Hypersil GOLD C18 column with a mixture of acetonitrile-ammonium formate (10mM) (80:20, v/v) as mobile phase. The ion transitions monitored were m/z 437.2 ? 114.2 for KR-62980, m/z 281.3 ? 86.1 for imipramine in multiple reaction monitoring (MRM) mode. The percent recoveries of KR-62980 and imipramine were 90.1 and 98.4% from rat plasma, respectively. The linear dynamic range extended from 0.01 to 10 ?g/ml with a correlation coefficient (R(2)) greater than 0.99 and the lower limit of quantification was 0.01 ?g/ml. The mean of intra- and inter-assay precisions was 2.1 and 9.3%. The method was validated and successfully applied to the pharmacokinetic study of KR-62980 in rat. PMID:20729023

Kim, Min-Sun; Song, Jin Sook; Roh, Hyeongjin; Park, Jong-Shik; Ahn, Jin Hee; Ahn, Sung-Hoon; Bae, Myung Ae

2010-07-30

371

Performance of a composite membrane bioreactor for the removal of ethyl acetate from waste air.  

PubMed

Ethyl acetate removal from an air stream was carried out by using a flat composite membrane bioreactor. The composite membrane consisted of a dense polydimethylsiloxane top layer with an average thickness of 0.3 ?m supported in a porous polyacrylonitrile layer (50 ?m). The membrane bioreactor (MBR) was operated during 3 months, and a maximum elimination capacity of 225 g m?³ h?¹ at an empty bed residence time of 60s was observed. Removal efficiencies higher than 95% were obtained for inlet loads lower than 200 g m?³ h?¹ and empty bed residence times as short as 15 s. The estimated yield coefficient, determined from the carbon dioxide production, resulted in 0.82 g dry biomass synthesized per gram of ethyl acetate degraded. No data of ethyl acetate treatment in MBR have been found in the literature, but the results illustrate that membrane bioreactors can potentially be a good option for its treatment. PMID:21763129

Álvarez-Hornos, F J; Volckaert, D; Heynderickx, P M; Van Langenhove, H

2011-06-23

372

Deuterium Exchange in Ethyl Acetoacetate: An Undergraduate GC-MS [Gas Chromatography-Mass Spectroscopy] Experiment  

ERIC Educational Resources Information Center

|The role of ethanol O-d in nullifying the deuterolysis may be demonstrated by determining that transesterification of methyl acetoacetate of the ethyl ester occurs as well as deuterium exchange of the five acetoacetate hydrogens. The significant acidity of the methylene protons in the acetoacetate group, the efficacy of base catalysis, the role…

Heinson, C. D.; Williams, J. M.; Tinnerman, W. N.; Malloy, T. B.

2005-01-01

373

Properties of treated papers and plastic film influencing ethyl ester transfer  

Microsoft Academic Search

The objective of this work was to compare and understand the aroma compound barrier property of two impregnated–supercalendered papers, with or without surface coating, and one plastic film (BOPP) in standard conditions of temperature (25°C) and relative humidity gradient (50%) for foodstuff storage. For that purpose, solubility, diffusivity and permeability coefficients were determined for a homologous series of ethyl esters

Cécile Dury-Brun; Pascale Chalier; Stéphane Desobry; Andrée Voilley

2008-01-01

374

Deuterium Exchange in Ethyl Acetoacetate: An Undergraduate GC-MS [Gas Chromatography-Mass Spectroscopy] Experiment  

ERIC Educational Resources Information Center

The role of ethanol O-d in nullifying the deuterolysis may be demonstrated by determining that transesterification of methyl acetoacetate of the ethyl ester occurs as well as deuterium exchange of the five acetoacetate hydrogens. The significant acidity of the methylene protons in the acetoacetate group, the efficacy of base catalysis, the role of…

Heinson, C. D.; Williams, J. M.; Tinnerman, W. N.; Malloy, T. B.

2005-01-01

375

Neurotoxicity Associated with Occupational Exposure to Acetone, Methyl Ethyl Ketone, and Cyclohexanone  

Microsoft Academic Search

The neurotoxic effects of acetone, methyl ethyl ketone (MEK), and cyclohexanone on Romanian workers and the impact of those effects on industry environmental standards have been controversial subjects. To scientifically substantiate the standards, a study was conducted on three groups of workers to determine the changes induced by ketone solvents on the central and peripheral nervous systems. Groups of exposed

E. Mitran; T. Callender; B. Orha; P. Dragnea; G. Botezatu

1997-01-01

376

DEVELOPMENT OF A PHYSIOLOGICALLY BASED PHARMACOKINETIC MODEL FOR METHYL ETHYL KETONE IN F344 RATS  

Microsoft Academic Search

A physiologically based pharmacokinetic (PBPK) model to describe the absorption, distribution, metabolism, and elimination of methyl ethyl ketone (MEK) in rats was developed. Partition coefficients were experimentally determined in rat tissues and blood samples using an in vitro vial equilibration technique. These solubility ratios were in agreement with previous human-based estimates that MEK is uniformly soluble within all tissues. The

Karla D. Thrall; Jolen J. Soelberg; Karl K. Weitz; Angela D. Woodstock

2002-01-01

377

Ethyl Vinyl Chloride Vapocoolant Spray Fails to Decrease Pain Associated with Intravenous Cannulation in Children  

Microsoft Academic Search

The purpose of the study was to determine the effect of ethyl vinyl chloride vapocoolant spray on pain reported by children undergoing intravenous cannulation. A randomized, double-blinded, placebo-controlled trial was conducted on eligible children between the ages of 9 and 18 years seen in a pediatric emergency department and requiring intravenous cannulation. Informed consent was obtained, and children were randomized

Mary Costello; Maria Ramundo; Norman C. Christopher; Keith R. Powell

2006-01-01

378

Carfentrazone-ethyl Pond Dissipation and Efficacy on Floating Plants 1  

Microsoft Academic Search

Carfentrazone-ethyl (CE) is a reduced risk herbicide that is currently being evaluated for the control of aquatic weeds. Greenhouse trials were conducted to determine efficacy of CE on water hyacinth ( Eichhornia crassipes (Mart.) Solms- Laub.), water lettuce ( Pistia stratiotes L.), salvinia ( Salvinia minima Baker) and landoltia (Landoltia punctata (G. Mey.) Les & D. J. Crawford ) .

TYLER J. KOSCHNICK; W. T. HALLER; A. W. CHEN

379

[Progesterone and pregnanediol-glucuronid concentrations in saliva, milk and urine of female alpacas and their application in pregnancy diagnosis].  

PubMed

The objective of the present study was the measurement of the pregnancy associated hormones progesterone (P4) and pregnanediol-glucuronide (PdG) in saliva, milk and urine of alpacas and their potential use in pregnancy diagnosis. Sample of blood, saliva, milk and urine were obtained from 36 female alpacas before mating and throughout the pregnancy. Concentrations of P4 and PdG were determined using an enzyme immunoassay (EIA). Pregnancy was checked by ultrasonography at any sampling time. The milk samples were also tested using a commercial on-farm progesterone kit which was designed for dairy cattle. EIA-Concentrations of P4 in blood, milk and urine and urine PdG concentrations were significantly higher in pregnant than in not pregnant alpacas. There was no difference in concentrations of P4 or PdG in saliva. The accuracy of the progesterone kit was 90% for diagnosis of pregnancy and 69% for non-pregnancy. However, 70% of the false positive results also showed relatively high P4 milk concentrations in the EIA. Values of P4 in blood and PdG in urine are comparable to previous reports in alpacas and therefore can be confirmed as an indicator for pregnancy. Saliva seems unsuitable in pregnancy diagnosis in alpacas, whereas milk seems to be an adequate alternative. The use of milk and urine would simplify the pregnancy diagnosis in alpacas since in contrast to the current methods (e. g. blood progesterone) the owners can take the samples. The avoidance of blood sampling results in a considerable stress reduction for the animals. P4 measurement in milk and PdG measurement in urine are good alternatives in pregnancy diagnosis during the first month of pregnancy, when a trans-abdominal ultrasonographic examination is not yet reliable. However, since high values of P4 and PdG only show the presence of active luteal tissue and therefore are indirect markers of pregnancy the diagnosis should be confirmed using ultrasound later in pregnancy. PMID:21141281

Volkery, Janine; Wittek, Thomas; Sobiraj, Axel; Gottschalk, Jutta; Einspanier, Almuth

380

Chemical and Enzyme-Assisted Syntheses of Norbuprenorphine-3-?-D-Glucuronide  

PubMed Central

Norbuprenorphine-3-?-D-glucuronide (nBPN-3-?-D-G, 1) is a major phase II metabolite of buprenorphine, a pharmaceutical used for the treatment of opioid addiction. The pharmacological activity of compound 1 is not clear because investigations have been limited by the lack of chemically pure, well characterized 1 in sufficient quantities for in vitro and in vivo experiments. This work describes two concise, new methods of synthesis of 1, a chemical and an enzyme-assisted synthesis. The chemical synthesis used a strategy based on a combination of Koenig-Knorr coupling and amino-silyl protection. The enzyme-assisted synthesis used dog liver to convert substrate norbuprenorphine (nBPN, 2) to 1. Both methods provided 1, characterized by 1H NMR and tandem mass spectrometry, with purity >96%. The fractional yield of the enzyme-assisted synthesis was greater than that of the chemical synthesis (67% vs 5.3%), but due to larger reaction volumes, the chemical synthesis afforded greater amounts of total 1.

Fan, Jinda; Brown, Sarah M.; Tu, Zhude; Kharasch, Evan D.

2011-01-01

381

Pulse radiolysis of aqueous solutions of ethyl acrylate and hydroxy ethyl acrylate  

NASA Astrophysics Data System (ADS)

Ethyl- and hydroxy ethyl acrylate show high reactivities with hydrated electron and hydroxyl radical intermediates of water radiolysis. The electron adduct reversibly protonate with pK values of 5.7 and 7.3. The adducts may take part in irreversible protonation at the ? carbon atom forming ?-carboxyl alkyl radicals. Same type of radical forms in reaction of acrylates with OH: at low concentration the adduct mainly disappear in self termination reactions. Above 5 mmol dm-1 the signals showed the startup of oligomerization.

Safrany, A.; Biro, A.; Wojnarovits, L.

1993-10-01

382

Pallidol hexa-acetate ethyl acetate monosolvate  

PubMed Central

The entire mol­ecule of pallidol hexa­acetate {systematic name: (±)-(4bR,5R,9bR,10R)-5,10-bis­[4-(acet­yloxy)phen­yl]-4b,5,9b,10-tetra­hydro­indeno­[2,1-a]indene-1,3,6,8-tetrayl tetra­acetate} is completed by the application of twofold rotational symmetry in the title ethyl acetate solvate, C40H34O12·C4H8O2. The ethyl acetate mol­ecule was highly disordered and was treated with the SQUEEZE routine [Spek (2009 ?). Acta Cryst. D65, 148–155]; the crystallographic data take into account the presence of the solvent. In pallidol hexa­acetate, the dihedral angle between the fused five-membered rings (r.m.s. deviation = 0.100?Å) is 54.73?(6)°, indicating a significant fold in the mol­ecule. Significant twists between residues are also evident as seen in the dihedral angle of 80.70?(5)° between the five-membered ring and the pendent benzene ring to which it is attached. Similarly, the acetate residues are twisted with respect to the benzene ring to which they are attached [C—O(carb­oxy)—C—C torsion angles = ?70.24?(14), ?114.43?(10) and ?72.54?(13)°]. In the crystal, a three-dimensional architecture is sustained by C—H?O inter­actions which encompass channels in which the disordered ethyl acetate mol­ecules reside.

Mao, Qinyong; Taylor, Dennis K.; Ng, Seik Weng; Tiekink, Edward R. T.

2013-01-01

383

Nonenzymatic hydrolysis of creatine ethyl ester  

Microsoft Academic Search

The rate of the non-enzymatic hydrolysis of creatine ethyl ester (CEE) was studied at 37°C over the pH range of 1.6–7.0 using 1H NMR. The ester can be present in solution in three forms: the unprotonated form (CEE), the monoprotonated form (HCEE+), and the diprotonated form (H2CEE2+). The values of pKa1 and pKa2 of H2CEE2+ were found to be 2.30

Nicholas S. Katseres; David W. Reading; Luay Shayya; John C. DiCesare; Gordon H. Purser

2009-01-01

384

Glucuronidation of the oxidative cytochrome P450-mediated phenolic metabolites of the endocrine disruptor pesticide: methoxychlor by human hepatic UDP-glucuronosyl transferases.  

PubMed

Methoxychlor, a currently used pesticide, is a proestrogen exhibiting estrogenic activity in mammals in vivo. Methoxychlor undergoes oxidative metabolism by cytochromes P450, yielding 1,1,1-trichloro-2-(4-hydroxyphenyl)-2-(4-methoxyphenyl)ethane (mono-OH-M) and 1,1,1-trichloro-2,2-bis(4-hydroxyphenyl)ethane (bis-OH-M) as main metabolites. Since humans may be exposed to these estrogenic metabolites, which are potential substrates of UDP-glucuronosyltransferases (UGTs), their glucuronide conjugation was investigated with human liver preparations and individual UGTs. Incubation of both mono-OH-M and bis-OH-M with human liver microsomes formed monoglucuronides. The structures of the glucuronides were identified by liquid chromatography/tandem mass spectometry. Examination of cDNA-expressed recombinant human hepatic UGTs revealed that several catalyze glucuronidation of both compounds. Among the cDNA-expressed UGT1A enzymes, UGT1A9 seemed to be the main catalyst of formation of mono-OH-M-glucuronide, whereas UGT1A3 seemed to be the most active in bis-OH-M-glucuronide formation. Furthermore, the chiral selectivity of mono-OH-M glucuronidation was examined. The results of the incubation of single enantiomers generally agreed with the chiral analyses of mono-OH-M derived from the glucuronidase digestion of the glucuronides of the racemic mono-OH-M. There was a relatively slight but consistent enantioselective preference of individual UGT1A1, UGT1A3, UGT1A9, and UGT2B15 enzymes for glucuronidation of the S- over the R-mono-OH-M, whereas in human liver microsomes differences were observed among donors in generating the respective R/S-mono-OH-M ratio. Since it was previously shown that human liver microsomes demethylate methoxychlor mainly into S-mono-OH-M, the observation that UGT1A isoforms preferentially glucuronidate the S-mono-OH-M suggests a suitable mechanism for eliminating this major enantiomer. This enantiomeric preference, however, is not extended to all samples of human liver microsomes that we tested. PMID:15205390

Hazai, Eszter; Gagne, Peter V; Kupfer, David

2004-07-01

385

Ethyl carbamate in foods and beverages: a review  

Microsoft Academic Search

Food and beverages contain many toxic chemicals that raise health concerns. Ethyl carbamate (EC) or urethane is the ethyl\\u000a ester of carbamic acid. It occurs at low level, from ng\\/L to mg\\/L, in many fermented foods and beverages. Ethyl carbamate\\u000a is genotoxic and carcinogenic for a number of species such as mice, rats, hamsters and monkeys. It has been classified

J. V. Weber; V. I. Sharypov

2009-01-01

386

Inhibitory activity of the ethyl acetate fraction from Viscum coloratum on bone resorption.  

PubMed

The effects of four fractions, a hexane fraction, an ethyl acetate fraction, an N-butanol fraction and a water fraction, from a water extract of Herba Visci were investigated to find the fraction, in IN VITRO experiments, with the greatest ability to inhibit the formation of osteoclast-like multinucleated cells from mouse bone marrow cells and also to inhibit (45)Ca release from a mouse parietal bone organ culture system. The ethyl acetate fraction was able to inhibit the formation of osteoclast-like cells in a dose-dependent manner and was also able to potently inhibit the release of (45)Ca even at a low concentration. Therefore, a further IN VIVO experiment was performed to determine if the ethyl acetate fraction had antiosteoporotic activity. It was found to inhibit the decreases in total and cancellous bone mineral density, in cancellous and cortical bone mineral content as well as in cortical bone thickness and in the X-axis strength index of tibiae of ovariectomized rats. The principle constituents of the ethyl acetate fraction were determined to be (+)-syringaresinol O- beta-glucopyranoside, 2-homoeriodictyol 7- O-glucoside and viscumneoside I by HPLC analysis. PMID:18247260

Yin, Jun; Han, Na; Xu, Xinyang; Liu, Zhihui; Zhang, Baoyan; Kadota, Shigetoshi

2008-02-04

387

A Simple and Efficient Synthesis of Ethyl and Methyl Glyoxylate  

Microsoft Academic Search

Ethyl and methyl glyoxylate are both prepared in high yields from an exchange reaction between the appropriate alkyl dialkoxyacetate and glyoxylic acid, followed by reaction with phosphorus pentoxide.

James M. Hook

1984-01-01

388

Adiabatic and nonadiabatic dissociation of ethyl radical  

NASA Astrophysics Data System (ADS)

Direct ab initio molecular dynamics using the trajectory surface hopping method with Tully's fewest switches simulates the photodissociation dynamics of ethyl radical, C2H5, following electronic excitation to the A~-state. Nonadiabatic dissociation dominates and produces ground state ethylene and fast hydrogen atoms with an anisotropic angular distribution. Surface hopping also generates hot ground state ethyl radicals followed ultimately by unimolecular dissociation to C2H4+H. The calculated excited state lifetime and the product recoil energy distribution obtained from an ensemble of trajectories are consistent with previous experiments and suggest that a strictly nonadiabatic mechanism can account for nonradiative decay. This process is in competition with adiabatic dissociation producing electronically excited state ethylene and H, a dissociation channel that has not yet been experimentally observed. The branching ratio between adiabatic and nonadiabatic dissociation pathways depends sensitively on the quality of the potential energy surfaces. At the multireference configuration interaction with singles and doubles level of theory, 15% of all trajectories dissociate adiabatically.

Hostettler, Jonas M.; Bach, Andreas; Chen, Peter

2009-01-01

389

Morphine-6-glucuronide: analgesic effects and receptor binding profile in rats  

SciTech Connect

The antinociceptive effects of morphine-6-glucuronide (M6G) were examined in two animal models of pain, the tail immersion test (reflex withdrawal to noxious heat) and the formalin test (behavioral response to minor tissue injury). In the tail immersion test, M6G produced and increase in withdrawal latency that rose rapidly between 0.01 and 0.025 ug ICV or 1 and 2 mg/kg SC. A further increase occurred at doses greater than 0.2 ug ICV or 4 mg/kg SC and was associated with marked catelepsy and cyanosis. Naloxone, 0.1 mg/kg SC, shifted the lower component of the dose-effect relation by a factor of 24. In the formalin test, 0.01 ug M6G ICV produced hyperalgesia, while between 0.05 and 0.2 ug ICV, antinociception increased rapidly without toxicity. The dose effect relations for hyperalgesia and antinociception were shifted to the right by factors of 20- and 3-fold, respectively. By comparison, ICV morphine was 60 (formalin test) to 145-200 (tail immersion test) times less potent than M6G. At sub-nanomolar concentrations, M6G enhanced the binding of (/sup 3/H)-etorphine, (/sup 3/H)-dihydromorphine and (/sup 3/H)-naloxone to rat brain membrane receptors by 20-40%. At higher concentrations, M6G displaced each ligand from binding sites, with K/sub i/ values of about 30 nM, as compared to morphine K/sub i/ values of about 3 nM.

Abbott, F.V.; Palmour, R.M.

1988-01-01

390

[Comparative bioavailability of eicosapentaenoic acid and docasahexaenoic acid from triglycerides, free fatty acids and ethyl esters in volunteers].  

PubMed

Comparative Bioavailability of Eicosapentaenoic Acid and Docosahexaenoic Acid from Triglycerides, Free Fatty Acids and Ethyl Esters in Volunteers. The bioavailability of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from triglycerides, free fatty acids and ethyl esters was investigated in 8 female volunteers in a randomized triple cross-over trial with baseline control. EPA/DHA was administered in capsules in form of triglycerides (1.68/0.72 g), free fatty acids (1.35/1.065 g) and ethyl esters (1.86/1.27 g). The resulting EPA/DHA plasma levels were determined and evaluated. The mean relative bioavailability of EPA/DHA compared to triglycerides was 186/136% from free fatty acids and 40/48% from ethyl esters. Maximal plasma levels were about 50% higher with free fatty acids and about 50% lower with ethyl esters as compared to triglycerides. The tolerability of the free fatty acids was much worse than that of triglycerides and ethyl esters. The main side effect was eructation. PMID:2144420

Beckermann, B; Beneke, M; Seitz, I

1990-06-01

391

Direct quantification of cannabinoids and cannabinoid glucuronides in whole blood by liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

The first method for quantifying cannabinoids and cannabinoid glucuronides in whole blood by liquid chromatography–tandem\\u000a mass spectrometry (LC–MS\\/MS) was developed and validated. Solid-phase extraction followed protein precipitation with acetonitrile.\\u000a High-performance liquid chromatography separation was achieved in 16 min via gradient elution. Electrospray ionization was\\u000a utilized for cannabinoid detection; both positive (?9-tetrahydrocannabinol [THC] and cannabinol [CBN]) and negative (11-hydroxy-THC [11-OH-THC], 11-nor-9-carboxy-THC [THCCOOH],

David M. Schwope; Karl B. Scheidweiler; Marilyn A. Huestis

392

New chiral auxiliaries in enantioselective heterogeneous catalytic hydrogenations: (?) and (+)-dihydro-apovincaminic acid. Comparison with (?)-dihydro-apovincaminic acid ethyl ester. III  

Microsoft Academic Search

The preparation, characterisation, use and comparison with (?)-dihydro-apovincaminic acid ethyl ester of (?) and (+)-dihydro-apovincaminic acid as chiral modifier in heterogeneous catalytic asymmetric hydrogenations are reported. The epimeric compositions were determined using NMR and HPLC methods.

G. Farkas; K. Fodor; A. Tungler; T. Máthé; G. Tóth; R. A. Sheldon

1999-01-01

393

Experimental vibrational study of imidazolium-based ionic liquids: Raman and infrared spectra of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and 1-ethyl-3-methylimidazolium ethylsulfate.  

PubMed

The vibrational structure of two room-temperature ionic liquids with the cation 1-ethyl-3-methylimidazolium [EMIM] and the respective anions bis(trifluoromethylsulfonyl)imide [TFSI] and ethylsulfate [EtOSO(3)] is investigated. In particular, attenuated total reflection (ATR) infrared (IR) as well as Raman spectra in the spectral range from 500 to 3500 cm(-1) have been recorded and analyzed. Moreover, the depolarization ratios of the Raman lines are determined. The individual peaks are assigned to the corresponding vibrational modes of the molecules. While the CH stretching region around 3000 cm(-1) is dominating in Raman spectra, it is remarkably weak in IR spectra. Finally, the results for 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide are compared to previous studies of single ions available in the literature. This comparison shows good agreement. PMID:18198022

Kiefer, Johannes; Fries, Juergen; Leipertz, Alfred

2007-12-01

394

Mechanisms of cyclisation of indolo oxime ethers I. Formation of ethyl 9,11-dimethoxy indolo[2,3- c]quinoline-6-carboxylates  

Microsoft Academic Search

The cyclisation of a series of ethyl 3?-aryl-4?,6?-dimethoxyindol-2?-yl-2-(hydroxyimino)acetates was investigated using 1H NMR spectroscopy to determine the mechanism of formation of the corresponding ethyl 9,11-dimethoxy indolo[2,3-c]quinoline-6-carboxylates. The electronic requirements of the reaction were determined and, along with the observation of an intermediate in the process, indicated that the reaction proceeds through an electrocyclic mechanism. The importance of the ester moiety

Kylie A. Clayton; David St C. Black; Jason B. Harper

2007-01-01

395

Nonenzymatic cyclization of creatine ethyl ester to creatinine  

Microsoft Academic Search

Creatine ethyl ester was incubated at 37°C in both water and phosphate-buffered saline and the diagnostic methylene resonances in the 1H NMR spectrum were used to identify the resultant products. It was found that mild aqueous conditions result in the cyclization of creatine ethyl ester to provide inactive creatinine as the exclusive product, and this transformation becomes nearly instantaneous as

Matthew W. Giese; Carl S. Lecher

2009-01-01

396

Cognitive effects of creatine ethyl ester supplementation.  

PubMed

Supplementation with creatine-based substances as a means of enhancing athletic performance has become widespread. Until recently, however, the effects of creatine supplementation on cognitive performance has been given little attention. This study used a new form of creatine--creatine ethyl ester--to investigate whether supplementation would improve performance in five cognitive tasks, using a double-blind, placebo-controlled study. Creatine dosing led to an improvement over the placebo condition on several measures. Although creatine seems to facilitate cognition on some tasks, these results require replication using objective measures of compliance. The improvement is discussed in the context of research examining the influence of brain energy capacity on cognitive performance. PMID:19773644

Ling, Jonathan; Kritikos, Minos; Tiplady, Brian

2009-12-01

397

A morphogenetic regulatory role for ethyl alcohol in Candida albicans.  

PubMed

Regulation of morphogenesis through the production of chemical signalling molecules such as isoamyl alcohol, 2-phenylethyl alcohol, 1-dodecanol, E-nerolidol and farnesol is reported in Candida albicans. The present study focuses on the effect of ethyl alcohol on C. albicans dimorphism and biofilm development. Ethyl alcohol inhibited germ tube formation induced by the four standard inducers in a concentration-dependent manner. The germ tube inhibitory concentration (4%) did not have any effect on the growth and viability of C. albicans cells. Ethyl alcohol also inhibited the elongation of germ tubes. Four percentage of ethyl alcohol significantly inhibited biofilm development on polystyrene and silicone surfaces. We suggest a potential morphogenetic regulatory role for ethyl alcohol, which may influence dissemination, virulence and establishment of infection. PMID:21605190

Chauhan, Nitin M; Raut, Jayant S; Karuppayil, S Mohan

2011-05-23

398

40 CFR 721.4250 - Hexanoic acid, 2-ethyl-, ethenyl ester.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Hexanoic acid, 2-ethyl-, ethenyl ester. 721...Chemical Substances § 721.4250 Hexanoic acid, 2-ethyl-, ethenyl ester. (a...chemical substance identified as hexanoic acid, 2-ethyl-, ethenyl ester...

2013-07-01

399

40 CFR 180.515 - Carfentrazone-ethyl; tolerances for residues.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Carfentrazone-ethyl; tolerances for residues...Specific Tolerances § 180.515 Carfentrazone-ethyl; tolerances for residues...for combined residues of the herbicide carfentrazone-ethyl...

2009-07-01

400

40 CFR 180.515 - Carfentrazone-ethyl; tolerances for residues.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Carfentrazone-ethyl; tolerances for residues...Specific Tolerances § 180.515 Carfentrazone-ethyl; tolerances for residues...for combined residues of the herbicide carfentrazone-ethyl...

2010-07-01

401

40 CFR 180.515 - Carfentrazone-ethyl; temporary tolerances for residues.  

Code of Federal Regulations, 2010 CFR

...1998-07-01 1998-07-01 false Carfentrazone-ethyl; temporary tolerances for...Specific Tolerances § 180.515 Carfentrazone-ethyl; temporary tolerances for...for combined residues of the herbicide carfentrazone-ethyl...

1998-07-01

402

40 CFR 721.10109 - Hexanoic acid, 2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane.  

Code of Federal Regulations, 2010 CFR

...2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane. 721...2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane. (a...2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane...

2009-07-01

403

40 CFR 721.10109 - Hexanoic acid, 2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane.  

Code of Federal Regulations, 2010 CFR

...2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane. 721...2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane. (a...2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane...

2010-07-01

404

USE OF ETHYL ALCOHOL TO INCREASE THE YIELD OF THE SZILARD-CHALMERS REACTION WITH ETHYL IODIDE  

Microsoft Academic Search

An alcoholic solution of ethyl iodide was subjected to the thermai ; neutron flux of Reaotor AGN 201 COSTANZA'' in Palermo. The Szilard-Chalmers ; reaction was produced and Ii¹²⁸ was liberated during the irradiation. The ; use of the ethyl alcohol as solvent minimized the retention. The gain in the ; yield seems to be very remarkable. (auth);

C. Cappadona; G. Fierotti; E. Sinagra

1959-01-01

405

Qualitative in vitro NMR analysis of creatine ethyl ester pronutrient in human plasma.  

PubMed

There are a number of forms of creatine available that attempt to improve the solubility and permeability, with the anticipation this will result in an improved pharmacokinetic profile and ultimately an enhanced ergogenic response. Previous research has shown that the different salt forms can improve solubility resulting in slightly altered pharmacokinetic profiles, however specific data exploring the conversion of esterified derivatives to creatine is lacking. The purpose of this study was to examine the assertion that creatine ethyl ester undergoes enzymatic conversion to creatine in human tissues. The IN VITRO response of creatine ethyl ester to incubation in human plasma was examined by H-NMR analysis. Lyophilized human plasma was reconstituted in D2O and phosphate-buffered saline and 1.5 mg of the analyte was added. Following incubation at 37 degrees C for 4 h and subsequent protein precipitation, the supernatant was analyzed by NMR, utilizing the diagnostic chemical shift of the methylene signal to determine the species present in solution, I.E. creatine ethyl ester, creatine, or creatinine. Both creatine and creatinine were run in parallel as control experiments and each assay was run in triplicate. As expected both creatine and creatinine remained unchanged. However, conversion of creatine ethyl ester to creatine by the esterases in human plasma was not observed to any detectable extent and the only species detected after the incubation period was creatinine. While not a definitive characterization of the IN VIVO behavior, these results strongly warrant a complete IN VIVO pharmacokinetic analysis of creatine ethyl ester since it appears these "pronutrients" may actually provide large exogenous sources of pharmacologically inactive creatinine rather than ergogenic creatine. PMID:19585404

Giese, M W; Lecher, C S

2009-07-07

406

Detection of acetaldehyde derived N(2)-ethyl-2'-deoxyguanosine in human leukocyte DNA following alcohol consumption.  

PubMed

Epidemiological studies have shown an association between alcohol (ethanol) consumption and increased cancer risk. The effect of alcohol consumption on the levels and persistence of N(2)-ethylidene-2'-deoxyguanosine (N(2)-ethylidene-dG) formed by acetaldehyde, the oxidative metabolite of ethanol, in human leukocyte DNA was investigated. DNA was isolated from venous blood samples obtained from 30 male non-smoking individuals before consumption of alcohol (0h) and subsequently at 3-5h following the consumption of 150mL of vodka (containing 42% pure ethanol). Additional samples were collected 24h and 48h post-alcohol consumption. The levels of N(2)-ethyl-2'-deoxyguanosine (N(2)-ethyl-dG) in the DNA were determined following reduction of N(2)-ethylidene-dG with sodium cyanoborohydride using a liquid chromatography-tandem mass spectrometry selected reaction monitoring method. A slight time-dependent trend showing an increase and decrease in the levels of N(2)-ethyl-dG was observed following consumption of alcohol compared to time 0h, however, the differences were not statistically significant. The average levels of N(2)-ethyl-dG observed at 0h, 3-5h, 24h and 48h time points following ingestion of alcohol were 34.6±21.9, 35.1±21.0, 36.8±20.7 and 35.6±21.1 per 10(8) 2'-deoxynucleosides, respectively. In conclusion, alcohol consumption that could be encountered under social drinking conditions, does not significantly alter the levels of the acetaldehyde derived DNA adduct, N(2)-ethyl-dG in human leukocyte DNA from healthy individuals. PMID:22824164

Singh, Rajinder; Gromadzinska, Jolanta; Mistry, Yogita; Cordell, Rebecca; Juren, Tina; Segerbäck, Dan; Farmer, Peter B

2012-07-20

407

Toxicological investigation of liquid petroleum gas explosion: human model for propane/ethyl mercaptan exposures.  

PubMed

Four individuals died as the result of a propane explosion. As with many propane explosions, the question was raised as to the adequacy of the product's odorization after the autopsy studies had been conducted. In most cases, this question leads to litigation. Ethyl mercaptan is a widely used odorant for propane and was used in this instance. Three of the four victims had blood available at autopsy for study. Quantitative analyses of the victims' blood, obtained during autopsy, were performed using gas chromatography/mass spectrometry, without subjecting the samples to hydrolysis. These analyses determined the relative amounts of propane and ethyl mercaptan in the blood to be 90, 63, and 175 mL/m3 headspace, and 0.36, 0.34, and 0.77 microgram/L blood, respectively. Since mercaptans have been reported in human blood as products of metabolism, modeling studies were conducted to establish the validity of the autopsy data and to develop an autopsy toxicology protocol for investigating explosion deaths. When subjects were not exposed to an atmosphere containing ethyl mercaptan, dimethylsulfide was the only mercaptan detectable in their blood without severe hydrolysis prior to analysis. Metabolic ethyl mercaptan is sufficiently bound to be undetectable by the methods used without hydrolysis. Human subjects were exposed to a flammable mixture of air and propane odorized with ethyl mercaptan. The analyses of the blood from these subjects produced results which were comparable with those for the explosion victims, establishing that the question of odorant adequacy can be addressed at the autopsy of propane explosion victims. It is extremely important that the pathologist and toxicologist investigating gas explosion deaths recognize the valuable evidence existing in the victim's blood. PMID:2066720

Lowry, W T; Gamse, B; Armstrong, A T; Corn, J M; Juarez, L; McDowell, J L; Owens, R

1991-03-01

408

Quantitative assay of lorazepam and its metabolite glucuronide by reverse-phase liquid chromatography-tandem mass spectrometry in human plasma and urine samples.  

PubMed

A LC/MS/MS method for the quantitative determination of lorazepam in human plasma and urine samples was developed and validated. The enantioselective assay allowed to separate the enantiomers and to verify the stereochemical instability of lorazepam. The linearity assessed for lorazepam unchanged was 0.2-20 ng of each enantiomer/ml plasma and 0.2-15 ng of each enantiomer/ml urine. The linearity assessed for total lorazepam (after enzymatic hydrolysis) was 1-30 ng of each enantiomer/ml plasma and 10-150 ng of each enantiomer/ml urine. The coefficients of variation obtained for the intra- and interassay precision were less than 15%. The method was applied to the investigation of the kinetic disposition and metabolism of racemic lorazepam administered as a single oral dose of 2 mg to a parturient. The occurrence of racemization required the calculation of the pharmacokinetic parameters as enantiomeric mixtures of lorazepam (t(1/2a) 3.5h; K(a) 0.198 ngh(-1); t(1/2) 11.5h; beta 0.060 h(-1); AUC(0-infinity) 192.1ngh/ml; CLt/f 2.41ml/minkg; Vd/f 173.5l; Fel 0.41%, and Cl(R) 0.0099 ml/minkg) and its metabolite lorazepam-glucuronide (t(1/2f) 1.2h; K(f) 0.578 h(-1); t(1/2) 16.6h; beta 0.042 h(-1); AUC(0-infinity) 207.6 ngh/ml; Fel 51.80%, and Cl(R) 98.32 ml/minkg). However, the determined confidence limits make the method suitable for application to clinical pharmacokinetic studies, even if the quantification of both the enantiomers is required. PMID:16243469

Papini, Olga; Bertucci, Carlo; da Cunha, Sergio Pereira; Dos Santos, Neife Aparecida Guinaim; Lanchote, Vera Lucia

2005-10-21

409

Thermodynamic and transport properties for coal mixtures. Technical progress report, January 1, 1985-March 31, 1985. [Methyl ethyl ketone, methyl acetate, ethyl acetate  

SciTech Connect

During this period, additional progress has been made on the development of procedures for the calculation of the thermodynamic and transport properties of polar coal mixtures. Experimental data have also been obtained on infinite dilution activity coefficients of polar systems by gas chromatographic procedures. In Figure 1, experimental molar volumes for the ammonia-methane system with x/sub NH/sub 3// = 0.3284 are compared with the values calculated with the equation of state of Wu and Stiel with parameters T/sub CM/, P/sub CM/, ..omega../sub M/, and Y/sub M/ determined from the parameters of the components. It can be seen that good agreement is obtained by this procedure. The analytical procedures have also been extended to polar-polar systems. In Figure 2, calculated bubble point pressures for the acetone-methyl ethyl ketone system at several temperatures are shown to agree closely with experimental values for the entire temperature range. Experimental values of infinite dilution activity coefficient have been obtained by gas chromatographic procedures for polar solutes including acetone, methyl ethyl ketone, methyl acetate, ethyl acetate, and n-propyl alcohol in n-decane for temperatures from 50 to 60/sup 0/C. 4 refs., 5 figs., 1 tab.

Stiel, L.I.

1985-01-01

410

Highly sensitive sites for guanine-O6 ethylation in rat brain DNA exposed to N-ethyl-N-nitrosourea in vivo.  

PubMed Central

Brain chromosomal DNA isolated from fetal BDIX-rats 1 h after i.v. administration of the ethylating N-nitroso carcinogen N-ethyl-N-nitrosourea (75 micrograms/g body weight), statistically contained one molecule of O6-ethyl-2'-deoxyguanosine (O6-EtdGuo) per 81 micron of DNA, as determined in enzymatic DNA hydrolysates by competitive radio-immunoassay using a high-affinity anti-(O6-EtdGuo) monoclonal antibody (ER-6). After fragmentation of the DNA by the restriction enzyme AluI (average fragment length, Lav = 0.28 micron = 970 bp; length range, Lr = 1.87-0.02 micron = 6540 - 60 bp), a small (approximately 2%) fraction of DNA enriched in specific polypeptides tightly associated with DNA was separated from the bulk DNA by a glass fiber binding technique. As analyzed by immune electron microscopy, approximately 1% of the DNA molecules in this fraction contained clusters of 2-10 (O6-EtdGuo)-antibody binding sites (ABS). On the cluster-bearing fragments (Lav, 0.85 micron +/- 0.50 micron S.D.; corresponding to 2970 +/- 1760 bp) the average ABS-ABS interspace distance was 110 nm (= 390 bp; range approximately 9-600 nm), indicating a highly non-random distribution of O6-EtdGuo in target cell DNA. Images Fig. 2.

Nehls, P; Rajewsky, M F; Spiess, E; Werner, D

1984-01-01

411

Phosphate-Solubilizing and Plant-Growth-Promoting Pseudomonas aeruginosa PS1 Improves Greengram Performance in Quizalafop- p -ethyl and Clodinafop Amended Soil  

Microsoft Academic Search

The quizalafop-p-ethyl- and clodinafop-tolerant phosphate-solubilizing and plant-growth-promoting Pseudomonas\\u000a aeruginosa PS1 isolated from the rhizospheric soils of mustard was used to determine its phosphate-solubilizing activity and other plant-growth-promoting\\u000a traits both in the presence and absence of technical grade quizalafop-p-ethyl and clodinafop under in vitro conditions. Quizalafop-p-ethyl (at 40, 80, and 120 ppb) and clodinafop (at 400, 800, and 1200 ppb) reduced the P-solubilizing

Munees Ahemad; Mohammad Saghir Khan

2010-01-01

412

[Teratogenic action of ethyl-nitrosourea in Göttingen miniature pigs (author's transl)].  

PubMed

By i.p. application of 70 or 100 mg/kg ethyl-nitrosourea, resp., to gravide Göttingen miniature pigs on days 14 or 16, resp., of gestation massive malformations of the skeletal system were produced. The experiments demonstrated the teratogenic effect of ethylnitrosourea on non-rodents, ascertained the period of determination of the skeletal system in pigs, confirmed the concentration effect in teratogenesis as well as the ineffectiveness of biological barriers with adequately high dosages. PMID:1243047

Graw, J; Ivankovic, S; Berg, H; Schmähl, D

1975-10-01

413

Trinexapac-Ethyl and Nitrogen Effects on Creeping Bentgrass Grown under Reduced Light Conditions  

Microsoft Academic Search

T rees aredesirable on golf courses for aesthetics, Shade is a major cause of poor performance and loss of turf, golfer challenge, and historic reasons. However, especially on putting greens. The objectives of this study were to trees are a major cause of failure and poor performance determine the effects of trinexapac-ethyl (TE) (4-(cyclopropyl-alpha- of underlying turfgrasses, especially on putting

R. M. Goss; J. H. Baird; S. L. Kelm; R. N. Calhoun

2002-01-01

414

Induction of dominant lethal mutation in male mice by ethyl alcohol  

Microsoft Academic Search

THERE have been many studies of the effects of ethyl alcohol on reproductive performance and of the genetic aspects of this relationship1-10. But in spite of extensive investigations of the genetic determination of alcohol preference in experimental animals, there has been little research on other genetic aspects of alcohol consumption11-13. It has been assumed for a long time that alcohol

F. M. Badr; Ragaa S. Badr

1975-01-01

415

Human fatty acid ethyl ester synttiase-III gene: Genomic organization, nucleotide sequencing and chromosomal localization  

Microsoft Academic Search

The complete gene for human fatty acid ethyl ester Synthase-III(FAEES-III) was isolated from a human genomic lambda phage library forfunctional and structural determination. The gene spans approximately 3.3 kbwhich includes 791 base pairs of the 5' and 124 base pairs of the 3'flanking regions. The gene is comprised of seven exons and is interrupted bysix introns. Several transcription regulatory sequences

Puran S. Bora; Bandula L. Guruge; D. Douglas Miller; Bernard R. Chaitman; Wilbert Fortson

1997-01-01

416

Dehydration of fermentative 2,3-butanediol into methyl ethyl ketone  

Microsoft Academic Search

A solid acid catalyst consisted of sulfonic groups covalently bound to an inorganic matrice was developed to dehydrate 2,3-butanediol into methyl ethyl ketone. Rate constant and apparent activation energy of the dehydration reaction were determined. The decay course of the catalyst was a two-stage curve. The catalyst was deactivated more rapidly in the first stage than in the second stage.

Ai V. Tran; Robert P. Chambers

1987-01-01

417

Proteins and Metabolites Regulated by Trinexapac-ethyl in Relation to Drought Tolerance in Kentucky Bluegrass  

Microsoft Academic Search

Plants have developed various mechanisms in adaptation to water deficit stress, including growth retardant to reduce water\\u000a loss. Previous studies reported that plants treated with a growth inhibitor, trinexapac-ethyl (TE), had improved drought tolerance.\\u000a The objective of this study was to determine alterations in proteins and metabolite accumulation associated with drought tolerance\\u000a improvement in a perennial grass species, Kentucky bluegrass

Chenping Xu; Bingru Huang

418

Photodeactivation of ethyl violet: a potential hazard of Sodasorb.  

PubMed

Breathing circuit cannisters containing functional CO2 absorbent are critical to prevent rebreathing CO2 during general anesthesia using closed or semiclosed breathing systems. Ethyl violet is the indicator dye added to Sodasorb to indicate impending exhaustion of the absorbent. A case of CO2 rebreathing due to failure of ethyl violet indicator in exhausted Sodasorb was encountered. Laboratory investigation demonstrated that dye failure could result from photodeactivation caused by fluorescent lights. Using a fixed intensity fluorescent light source and quantitative spectrophotometric analysis, a highly significant dose-response relationship was demonstrated between duration of light exposure and the decrease in ethyl violet concentration. After 24 h of fluorescent light exposure with a received flux density of 46 nwatts/cm2 at 254 nm, the concentration of functional ethyl violet remaining in pulverized Sodasorb was 16% of the baseline value. Furthermore, using multiple light sources of various intensities, the greater the intensity of light, the more rapid the rate of decline of the ethyl violet concentration. It is recommended to minimize the problem by using ultraviolet filters and incorporating additional ethyl violet in Sodasorb. Finally, ethyl violet undergoes temporal deactivation after a Sodasorb container is opened, even if it is stored in the dark. PMID:2105069

Andrews, J J; Johnston, R V; Bee, D E; Arens, J F

1990-01-01

419

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

PubMed

Breast and prostate constitute organs of intense steroidogenic activity. Clinical and epidemiologic data provide strong evidence on the influence of androgens and estrogens on the risk of typical hormone-dependent malignancies, like breast and prostate cancer. Recent studies have focused on the role of androgen metabolites in regulating androgen concentrations in hormone-sensitive tissues. Steroid glucuronidation has been suggested to have a prominent role in controlling the levels and the biological activity of unconjugated androgens. It is well-established that serum levels of androgen glucuronides reflect androgen metabolism in androgen-sensitive tissues. Quantitative analysis of androgen metabolites in blood specimens is the only minimally invasive approach permitting an accurate estimate of the total pool of androgens. During the past years, androgen glucuronides analysis most often involved radioimmunoassays (RIA) or direct immunoassays, both methods bearing serious limitations. However, recent impressive technical advances in mass spectrometry, and particularly in high performance liquid chromatography coupled with mass spectrometry (LC-MS/MS), have overcome these drawbacks enabling the simultaneous, quantitative analysis of multiple steroids even at low concentrations. Blood androgen profiling by LC-MS/MS, a robust and reliable technique of high selectivity, sensitivity, specificity, precision and accuracy emerges as a promising new approach in the study of human pathology. The present review offers a contemporary insight in androgen glucuronides profiling through the application of LC-MS/MS, highlighting new perspectives in the study of steroids and their implication in hormone-dependent malignancies. PMID:24140653

Kalogera, Eleni; Pistos, Constantinos; Provatopoulou, Xeni; Athanaselis, Sotirios; Spiliopoulou, Chara; Gounaris, Antonia

2013-09-27

420

Synthesis and chromatographic evaluation of molecularly imprinted polymers prepared by the substructure approach for the class-selective recognition of glucuronides  

Microsoft Academic Search

Two series of molecularly imprinted polymers (MIPs) for the class-selective recognition of glucuronides have been prepared by using lipophilic substructures of the target analyte as template molecule and potent host monomers against oxyanions, that are expected to establish a strong stoichiometric interaction with the single carboxylic group of the template. The polymers were tested as stationary phases in liquid chromatography

S. Ambrosini; M. Serra; S. Shinde; B. Sellergren; E. De Lorenzi

2011-01-01

421

Enantioselective Reformatsky reaction of ethyl iododifluoroacetate with ketones.  

PubMed

Two approaches have been developed for the enantioselective Reformatsky reaction of ethyl iododifluoroacetate with ketones to form a quaternary carbon centre using (1R,2S)-1-phenyl-2-(1-pyrrolidinyl)-1-propanol as the chiral ligand. Good yields and high enantioselectivities (80-91% ee) were achieved with a range of alkyl aryl ketones in a convenient one-pot protocol using ethyl iododifluoroacetate and diethylzinc to form the difluorinated Reformatsky reagent homogeneously. In the traditional two-step Reformatsky reaction using the preformed Reformatsky reagent generated from ethyl iododifluoroacetate and zinc dust, good yields and good enantioselectivities (75-84% ee) were also obtained. PMID:22421710

Fornalczyk, Michal; Singh, Kuldip; Stuart, Alison M

2012-03-15

422

Non-Steroidal Anti-Inflammatory Drugs Do Not Influence the Urinary Testosterone/Epitestosterone Glucuronide Ratio  

PubMed Central

The UDP Glucuronosyl Transferase (UGT) enzymes are important in the pharmacokinetics, and conjugation, of a variety of drugs including non-steroidal anti-inflammatory drugs (NSAIDs) as well as anabolic androgenic steroids (AAS). Testosterone glucuronidation capacity is strongly associated with a deletion polymorphism in the UGT2B17 gene. As the use of high doses of NSAIDs has been observed in athletes there is a risk for a drug–drug interaction that may influence the doping tests for AAS. In vitro studies show inhibitory potential on UGT2B7, 2B15, and 2B17 enzymes by NSAIDs. The aim of this study was to investigate if concomitant use of NSAIDs and a single dose of testosterone enanthate would affect the excretion rate of testosterone and epitestosterone glucuronide (TG and EG) as well as the T/E ratio, thereby affecting the outcome of the testosterone doping test. The study was designed as an open, randomized, cross-over study with subjects being their own control. The 23 male healthy volunteers, with either two, one or no allele (ins/ins, ins/del, or del/del) of the UGT2B17 gene, received the maximum recommended dose of NSAID (Ibuprofen or Diclofenac) for 6?days. On day three, 500?mg of testosterone enanthate was administered. Spot urine samples were collected for 17?days. After a wash-out period of 4?months the volunteers received 500?mg testosterone enanthate only, with subsequent spot urine collection for 14?days. The glucuronides of testosterone and epitestosterone were quantified. NSAIDs did not affect the excretion of TG or EG before the administration of testosterone. The concomitant use of NSAIDs and testosterone slightly increased the TG excretion while the EG excretion was less suppressed compared to testosterone use only. The effects of the NSAIDs on the TG and EG excretion did not differ between the UGT2B17 genotype groups. In conclusion, the outcome of testosterone doping tests does not seem to be affected by the use of NSAIDs.

Lundmark, Jonas; Garevik, Nina; Thorngren, John-Olof; Garle, Mats; Ekstrom, Lena; Rane, Anders; Schulze, Jenny J.

2013-01-01

423

Non-steroidal anti-inflammatory drugs do not influence the urinary testosterone/epitestosterone glucuronide ratio.  

PubMed

The UDP Glucuronosyl Transferase (UGT) enzymes are important in the pharmacokinetics, and conjugation, of a variety of drugs including non-steroidal anti-inflammatory drugs (NSAIDs) as well as anabolic androgenic steroids (AAS). Testosterone glucuronidation capacity is strongly associated with a deletion polymorphism in the UGT2B17 gene. As the use of high doses of NSAIDs has been observed in athletes there is a risk for a drug-drug interaction that may influence the doping tests for AAS. In vitro studies show inhibitory potential on UGT2B7, 2B15, and 2B17 enzymes by NSAIDs. The aim of this study was to investigate if concomitant use of NSAIDs and a single dose of testosterone enanthate would affect the excretion rate of testosterone and epitestosterone glucuronide (TG and EG) as well as the T/E ratio, thereby affecting the outcome of the testosterone doping test. The study was designed as an open, randomized, cross-over study with subjects being their own control. The 23 male healthy volunteers, with either two, one or no allele (ins/ins, ins/del, or del/del) of the UGT2B17 gene, received the maximum recommended dose of NSAID (Ibuprofen or Diclofenac) for 6?days. On day three, 500?mg of testosterone enanthate was administered. Spot urine samples were collected for 17?days. After a wash-out period of 4?months the volunteers received 500?mg testosterone enanthate only, with subsequent spot urine collection for 14?days. The glucuronides of testosterone and epitestosterone were quantified. NSAIDs did not affect the excretion of TG or EG before the administration of testosterone. The concomitant use of NSAIDs and testosterone slightly increased the TG excretion while the EG excretion was less suppressed compared to testosterone use only. The effects of the NSAIDs on the TG and EG excretion did not differ between the UGT2B17 genotype groups. In conclusion, the out