Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.31 (beta-glucuronidase)
7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dextromethorphan (DEM) is a widely used probe drug for human cytochrome P450 2D6 isozyme activity assessment by measuring the ratio between DEM and its N-demethylated metabolite dextrorphan (DOR). DOR is excreted in urine mainly conjugated to glucuronic acid. Prior to quantification, DOR must be deconjugated to avoid variability caused by the polymorphic glucuronosyltransferase enzyme. A chemical hydrolysis method was optimized using a chemometric approach. Three factors (acid concentration, hydrolysis time and temperature) were selected and simultaneously varied to study their effect on conjugated DOR hydrolysis. Hydrolysis conditions that maximize DOR release without significant degradation of both DEM and DOR were chosen and results were compared to those obtained by enzymatic method using beta-glucuronidase. An HPLC method with fluorescence detection was developed for the simultaneous quantitation of DEM, DOR and levallorphan, used as an internal standard. Separation was performed on a phenyl analytical column (150 mmx4.6 mm i.d., 5 microm) with a mobile phase consisting of 18% acetonitrile and 50 mM phosphoric acid (pH 3). The overall analytical procedure was validated and showed good performances in terms of selectivity, linearity, sensitivity, precision and accuracy. Finally, this assay was used to determine DEM/DOR molar ratios in fibromyalgia patients for the purpose of determining phenotype status for the CYP2D6.
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PMID:Development and validation of a chemical hydrolysis method for dextromethorphan and dextrophan determination in urine samples: application to the assessment of CYP2D6 activity in fibromyalgia patients. 1806 99

A high performance liquid chromatography-electrospray ionization mass spectrometry (LC-ESI/MS) was developed to screen and determine trenbolone, tetrahydrogestrinone and gestrinone in human urine. The urine sample was enzymatically hydrolyzed with beta-glucuronidase, then extracted with methyl tert-butyl ether. Chromatographic separation was performed on a Zorbax SB-C18 column (150 mm x 2.1 mm, 5 microm) with ammonium formate buffer (pH 3.5) and acetonitrile as mobile phase. Using positive electrospray ionization mode, the effect of different parameters from electrospray chamber was investigated. The limits of detection based on signal noise ratio of 3 were between 1 and 5 ng. The method can be applied in screening and confirmation of the anabolic steroids in doping control.
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PMID:[Determination of three anabolic steroids by liquid chromatography-mass spectrometry]. 1895 43

Taxifolin has been widely used in the treatment of cerebral infarction and sequelae, cerebral thrombus, coronary heart disease and angina pectoris. A reliable sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) method with UV detection for the pharmacokinetic study of taxifolin in rabbit plasma after enzymatic hydrolysis was developed and validated for the first time. Taxifolin, with biochanin A as the internal standard, was extracted from plasma samples by liquid/liquid extraction after hydrolysis with beta-glucuronidase and sulfatase. Chromatographic separation was conducted on a Luna C18 column (4.6 mm x 150 mm, 5 microm particle size) and pre-column (2.0 mm, the same sorbent). Two-step linear gradient elution with acetonitrile and 0.03% water solution of trifluoroacetic acid as mobile phase at a flow rate of 1.0 ml/min was used. The UV detector is set at 290 nm. The elution time for taxifolin and biochanin A was approximately 7.9 and 18.3 min, respectively. The calibration curve of taxifolin was linear (r > 0.9997) over the range of 0.03-5.0 microg/ml in rabbit plasma. The limit of detection (LOD) and limit of quantification (LOQ) for taxifolin were 0.03 and 0.11 microg/ml, respectively. The present method was successfully applied for the estimation of the pharmacokinetic parameters of taxifolin following intravenous and oral administration of lipid solution to rabbits. The absolute bioavailability of taxifolin after oral administration of lipid solution was 36%.
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PMID:Determination and pharmacokinetic study of taxifolin in rabbit plasma by high-performance liquid chromatography. 1911 Apr 6

A liquid chromatography tandem mass spectrometry (LC/MS(n)) method for the determination of 12 corticosteroids in bovine liver has been optimized and validated in accordance with the European Commission Decision 2002/657/EC. A bovine liver sample was deconjugated with beta-glucuronidase/sulfatase enzyme, extracted with diethyl ether and further cleaned up with Solid Phase Extraction (SPE) before analysis with LC/MS(n). Two different enzyme extracts (originating from Helix Pomatia and Keyhole Limpet) and three SPE elution solvents (ethyl acetate, acetonitrile and methanol) were compared during the optimization. Helix Pomatia is generally known as the enzyme most being used for enzymatic hydrolysis purposes. Nevertheless, when detecting corticosteroids in the low microg kg(-1) concentration range, the Helix Pomatia extract may lead to interferences in the final LC/MS(n) chromatogram. When using the Keyhole Limpet enzyme extract, no interferences were observed and therefore, this extract was the best choice for enzymatic hydrolysis tested in this case. Ethyl acetate was used as elution solvent during the validation procedure since SPE elution with acetonitrile resulted in higher chromatographic backgrounds, while elution with methanol showed less reproducible results. Validation of the optimized method was carried out for 10 of the 12 corticosteroids, giving mean recoveries between 91 and 109%, and repeatability and reproducibility coefficients of respectively maximum 13.7 and 18.0%. The working ranges for the linear calibration curves were 5-20 microg kg(-1) for prednisolone, methylprednisolone and prednisone and 0.5-4 microg kg(-1) for the other compounds (coefficients of determination R(2)> or =0.97). Specificity, decision limit (CCalpha) and detection capability (CCbeta) were for all compounds within the EC specified limits.
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PMID:Optimization and validation of a liquid chromatography tandem mass spectrometry (LC/MSn) method for analysis of corticosteroids in bovine liver: evaluation of Keyhole Limpet beta-glucuronidase/sulfatase enzyme extract. 1921 13

Opiates and opioids currently rank among the most commonly prescribed pain medications. We describe two liquid chromatography tandem mass spectrometry (LC-MS-MS) methods for the quantification of morphine, codeine, hydrocodone, hydromorphone, oxycodone, oxymorphone, and 6-monoacetylmorphine (6-MAM). In the first, urine samples are pretreated by acidifying with sodium acetate containing appropriate deuterated internal standards and hydrolyzed with beta-glucuronidase. Samples are cooled, diluted with water, vortexed, centrifuged, and a portion is transferred to an autosampler vial for analysis. The second method allows for the measurement of the compounds in blood, serum, or plasma specimens. Analysis of these samples involves pretreatment with acetonitrile containing deuterated internal standards to deproteinize the sample, which is subsequently vortexed and centrifuged. A portion of the organic layer is transferred to a clean test tube, dried under nitrogen, and reconstituted with water for analysis. Quantitation of analytes is accomplished using a commercially available single-point calibrator (urine samples) or an in-house prepared six-point standard curve (blood samples).
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PMID:Quantitation of morphine, codeine, hydrocodone, hydromorphone, oxycodone, oxymorphone, and 6-monoacetylmorphine (6-MAM) in urine, blood, serum, or plasma using liquid chromatography with tandem mass spectrometry detection. 2007 93

A method was developed for the simultaneous determination and identification of 12 steroid hormone residues in pig tissues, including stanolone, aldosterone, boldenone, danazol, metandienone, methyltestosterone, nadrolone, norethindrone, progesterone, stanozolol, testosterone and testosterone propionate, using liquid chromatography-tandem triple-quadrupole linear ion trap mass spectrometry(LC-MS/MS). Homogenized pig tissue samples were purified with a Waters MCX solid phase extraction column after enzymatic hydrolysis by beta-glucuronidase, then separated on a Venusil MP C18 column (100 mm x 2, 1 mm, 3 microm) using gradient elution with the mobile phases of acetonitrile and water with 0.1% (v/v) formic acid. A multiple reaction monitoring (MRM) as survey scan and an enhanced product ion (EPI) scan as dependent scan were performed in an information dependent acquisition (IDA) experiment. The compound identification was carried out by library search with a newly developed MS/MS library based on EPI spectra at three different collision energies in positive mode. The results showed that the limits of detection (LODs, S/N = 3) were in the range of 0.2 - 0.5 microg/kg for the steroid hormones, and with a good linearity (r > 0.99) ranged from 0.5 to 100.0 microg/L. The average recoveries (n = 6) of the 12 steroid hormones spiked in pig tissue samples at 5.0 microg/kg ranged from 72.0% to 98.1% with the relative standard deviations (RSDs) between 3.1% and 12.5%. The method was applied for the qualitative and quantitative determination of steroid hormone residues in pig tissues with sensitive and accurate characteristics.
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PMID:[Determination of 12 steroid hormone residues in pig tissues by liquid chromatography-tandem mass spectrometry combining with library search]. 2212 32

The novel melatonin agonist Neu-P11 is used in treatment of physiological insomnia. In animal studies Neu-P11 showed sleep-promoting effects. In a phase 1 study Neu-P11 was administered to cohorts of healthy young male volunteers in an ascending single dose study. Up to now the metabolism of this new drug in humans has not been investigated. The first aim of this study was to identify possible metabolites in pooled urine samples of the first collecting period (0-8 h) of volunteers with the highest Neu-P11 oral dosage (200 mg). The objective of the second part of the study was to estimate the concentrations of the main metabolites of Neu-P11 - in this urine sample. The analyte Neu-P11 and metabolites were separated from human urine using dilution and precipitation with acetonitrile. Samples were analyzed for formation of both phase I and phase II metabolites using LC-MS/MS in precursor ion mode, product ion mode, neutral loss mode and the multi-reaction monitoring mode (MRM). Urine samples were analyzed before and after addition of beta-glucuronidase and sulfatase. In the pooled urine sample eight metabolites could be proved. The parent drug, the sulfated demethylated Neu-P11, the sulfated 6OH-Neu-P11 and the di-oxygenated product gave the highest signals in these urine samples and probably had the highest concentration. But quantification without reference substances is not possible. So in the second part of the study the urine samples were additionally analyzed with UV-detection for a better estimation of the metabolite concentrations. The concentration of the sulfated metabolites was more than ten times higher than the concentration of the unchanged drug in urine. Other metabolites were not measurable with UV-detection. The di-oxygenated Neu-P11 and an additional mono-oxygenated Neu-P11 showed relatively high signals in MS/MS. Probably the other metabolites, namely glucuronides, unconjugated demethylated Neu-P11 and unconjugated 6OH-Neu-P11, were formed at a lesser extent.
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PMID:Elucidation of Neu-P11 metabolism in urine of volunteers by liquid chromatography-tandem mass spectrometry. 2333 48

A highly sensitive method using ultra-fast liquid chromatography coupled with quadrupole/linear ion trap mass spectrometry (UFLC-Q/Trap MS) was developed to simultaneously screen and confirm nine beta-blockers (BBs) in porcine tissues (porcine muscle, liver and kidney). The method was used for trace determination of atenolol, pindolol, acebutolol, metoprolol, carazolol, labetalol, bisoprolol, propranolol and penbutolol. The homogenized tissues were hydrolyzed by beta-glucuronidase/aryl sulfatase and extracted with acetonitrile, followed by continuous purification procedures of disperse solid phase extraction (d-SPE) with diatomaceous earth and BondElut cartridge. The ultra-fast chromatographic separation was conducted on a Kinetex C18-XB column (150 mm x 2.1 mm, 2.6 microm) using 0.1% (v/v) formic acid aqueous solution and methanol as mobile phases in gradient elution. The optimized ion transitions were mployed in the mixed-mode of scheduled multiple reaction monitoring (sMRM) -information dependent acquisition (IDA)-enhanced product ion (EPI) scan. Qualification analysis was performed through spectra-matching with on-line lab-built MS/MS library. For quantification stable isotope-labelled analogues of the analytes were used as internal standards. As a result, in porcine liver, kidney and muscle, the nine BBs showed good linearity with all the correlation coefficients (r) more than 0.995 in the range of 0.1-20 microg/L. The limits of quantification (LOQ, S/N > or = 10) were 0.5 kg/kg for all the analytes. The developed method gave average recoveries of 87.5%-111.8% spiked at 0.5, 1.0 and 5.0 microg/kg with the relative standard deviations of 4.0%-12. 5%. The proposed method can be used to screen and confirm the nine BBs in a single run, which makes it effective in surveillance and detection of the BBs residues in porcine tissues.
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PMID:[Simultaneous determination of nine beta-blockers in porcine tissues by ultra-fast liquid chromatography coupled with quadrupole/linear ion trap mass spectrometry]. 2526 53

A combination immunoaffinity column (IAC-CZ) clean-up and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analytical method was successfully developed for zearalenol, beta-zearalenol and zearalenone) and chloramphenicol (CAP) in foodstuffs of animal origin. The samples (fish, liver, milk and honey) were enzymatically digested by beta-glucuronidase/sulfatase for about 16 h and then extracted with ether. The extracts were evaporated to dryness and then the residues were dissolved by 1.0 mL of 50% acetonitrile solution. After filtered and diluted with PBS buffer, the reconstituted solution were cleaned-up with a IAC-CZ and then analyzed by LC-MS/MS in multiple reaction monitoring (MRM) mode. The chromatographic separation was performed on a Shimadzu Shim-pack VP-ODS column with gradient elution by acetonitrile and 2 mmol/L ammonium acetate solution. The detection was carried out by electrospray negative ionization mass spectrometry in MRM mode. The proposed method was validated by the limit of detection (0.04-0.10 microg/kg), linearity (R2 > or = 0.999 0), average recoveries (70.9%-95.6%) and precisions (2.0% - 11.8%). The developed method is reliable, sensitive and has good applicability. The combination immunoaffinity column was proved to be an effective pretreatment technique to decrease the matrix effect, and it met the requirements of residue analysis of co-occurring zeranols and chloramphenicol.
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PMID:[Simultaneous determination of zeranols and chloramphenicol in foodstuffs of animal origin by combination immunoaffinity column clean-up and liquid chromatography-tandem mass spectrometry]. 2526 64


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