摘要:

AbstractA reversed‐phase HPLC method for the determination of epinephrine, norepinephrine, dopamine, and vanillylmandelic acid (VMA) has been developed. The concentration of VMA in the urine of hypertensive patients was measured by direct injection after centrifugation. The method is useful for the diagnosis of pheochromocytom

ISSN:0269-3879    

DOI:10.1002/bmc.1130020102

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractA simple and effective chemical method has been developed for quantitatively reducing quinones, which is based on their reaction with zinc metal and zinc ions. Comparison of this method with conventional electrochemical reduction revealed the chemical method to be considerably superior. The reduction of quinones to their corresponding hydroquinones was verified by ultraviolet spectrophotometry. The reduction methodology has been applied to derivatize phylloquinone and its metabolite, namely phylloquinone 2,3‐epoxide, ‘on‐line’, with subsequent fluorometric detection of the generated hydroq

ISSN:0269-3879    

DOI:10.1002/bmc.1130020103

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractA simple and highly sensitive method for the determination of free and total (free + conjugated) catecholamines (norepinephrine, epinephrine and dopamine) in human urine is described which employs HPLC with fluorescence detection. Conjugated catecholamines (sulfate form) are hydrolyzed by a sulfatase‐mediated reaction to the corresponding free amines. After cation exchange chromatography on a Toyopak IC‐SPS cartridge, catecholamines and isoproterenol (internal standard) in urine samples were converted into the corresponding fluorescent compounds by reaction with 1, 2‐diphenylethylenediamine. These compounds were separated within 8 min on a reversed phase column with isocratic elution using a mixture of water, methanol and acetonitrile containing a Tris‐hydrochloric acid buffer (pH 7.0). The detection limit for each catecholamine is ca 2 fmol per 100 μL injectio

ISSN:0269-3879    

DOI:10.1002/bmc.1130020104

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractAn ion pair HPLC method which can simultaneously detect the major metabolites of an exocrine pancreatic function testing agent (NBT‐PABA) in plasma and urine has been developed. This assay has been applied to a pharmacokinetic study of PABA and its metabolites in 3 healthy adult volunteers following the oral administration of 1 g NBT‐PABA. The 6 h testing period currently used to collect urine following the NBT‐PABA ingestion is adequate for the recovery of PABA and its metabolites. Plasma determination of these compounds may provide an improved evaluation of the pancreatic performance in patients with abnormal liver or kidney fun

ISSN:0269-3879    

DOI:10.1002/bmc.1130020105

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractA rapid and specific HPLC method for the simultaneous determination of gastrodin and its metabolite gastrodigenin (p‐hydroxybenzyl alcohol) in rat plasma, bile, liver, urine and faeces is described. The separation was achieved by using a reversed phase column (YWG‐C18) eluted with methanol‐water (2.5:97.5 v/v). Phloroglucinolum was used as internal standard and the peaks were detected at UV 221 nm. The protein precipitation with ethanol was a very simple and rapid method for sample preparation. The gastrodin and gastrodigenin were quantitated by measuring the peak‐height ratios. There was a linear concentration range of 10–320 μg/mL in the assay for both compounds. The coefficients of variation (within‐day) for samples spiked with gastrodin and gastrodigenin were 2.94% and 3.08%, respectively. The method demonstrated a high specificity and was suitable for use in pharmacokin

ISSN:0269-3879    

DOI:10.1002/bmc.1130020106

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractA new hydrophobic interaction HPLC column is used for the rapid purification of proteinase inhibitors isolated from arrowhead. The inhibitors, partially purified by DEAE‐cellulose column chromatography, are resolved into three components with a mobile phase gradient of decreasing salt concentration from 1.1Mammonium sulfate in 0.01Mphosphate buffer to phosphate buffer alone. This new HPLC column is found to be very useful for rapid, semipreparative purification of hydrophobic protein and sample loading of up to 1.6 mg of inhibitors can be fully resolved on an analytical colum

ISSN:0269-3879    

DOI:10.1002/bmc.1130020107

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe three 2‐mercaptoethanol (ME) thioether conjugates of 2‐hydroxyacetanilide (2HAA) are detected and identified using liquid chromatography/electrochemistry (LC/EC). The conjugates are produced either by incubations of 2HAA with liver microsomes in the presence of NADPH and ME or by chemically oxidizing a solution of 2HAA and allowing it to react with ME. Identification of the three isomers is based on retention time and comparison of the electrochemical behavior of model compounds.Production of the three isomers by microsomal protein occurs only in the presence of NADPH and shows that 2HAA proceeds through a cytochrome P‐450 mediated pathway to a reactive intermediate similar to acetaminophen, possiblyN‐acetyl‐o‐quinoneimine.The relative percentages of each isomer produced were calculated as the percentage of the total peak areas of the isomers. Compound A (2HAA‐5‐ME) is produced in 53.7% and 24.6%, compound B (2HAA‐4‐ME) is produced in 16.2% and 70.3% and compound C (2HAA‐3‐ME) is produced in 30.1% and 5.1% by microsomal incubations and chemical

ISSN:0269-3879    

DOI:10.1002/bmc.1130020108

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractA method for determining plasma 3,4‐dihydroxyphenylethyleneglycol (DHPG), a central noradrenaline (NA) metabolite, is described. The method used HPLC with dual coulometric detection set in screen mode of operation. The isolation of DHPG and related catecholamines (noradrenaline, dopamine and dihydroxybenzylamine) was performed on acid washed alumina extracted with 0.2MHClO4containing EDTA (0.2%), and reduced glutathione as stabilizer. A reversed phase column with an eluting system containing 0.025Mcitric acid‐sodium hydrogen phosphate buffer in the ratio 3:2 (v:v) and 5% methanol was used. The experimental results of plasma DHPG levels compared favourably with the results from the literature, and a positively significant correlation with plasma MHPG was found. This method could be used as an alternative in central NA assessm

ISSN:0269-3879    

DOI:10.1002/bmc.1130020109

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractA simple HPLC method has been developed to measure the antiarrhythmic agent penticainide and itsN‐desalkyl metabolite in biological fluids. Solvent extraction of a small (200 μL) sample volume with direct analysis of the extract is used to measure the plasma and urinary concentrations of these compounds attained during chronic therapy, although a larger sample volume (1.0 mL) and prior concentration of the extract are required for single oral dose work. In each case chromatographic analysis is performed using a microparticulate (5 μm) silica column and methanolic ammonium perchlorate (10 mM, pH 6.7) as eluent with UV detection (260 nm). No endogenous sources of interference have been encountered and potential interference from other drugs is mini

ISSN:0269-3879    

DOI:10.1002/bmc.1130020110

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractWe describe a method for measuring adriamycin and its metabolites, adriamycinol and adriamycinone in plasma, using reversed phase HPLC and fluorescence detection. The lower limit of detection is approximately 1 ng/mL for each compound. An extraction technique for serum is described which is capable of an almost equal recovery (>93%) of adriamycin and metabolites without interference from endogenous components of plasma and from other common drugs. Within‐day and day to day coefficients of variation are estimate

ISSN:0269-3879    

DOI:10.1002/bmc.1130020111

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY