摘要:

AbstractLead exposure causes increases in urinary coproporphyrin excretion and the accumulation of zinc protoporphyrin in red cells. In the conventional view of the effect of lead on haem biosynthesis, the accumulation of these metabolites results from lead inhibition of two of the mitochondrial enzymes of haem biosynthesis, corproporphyrinogen oxidase (EC 1.3.3.3.) and ferrochelatase (EC 4.99.1.1). This review critically assesses the evidence for the inhibition of these enzymes. We consider this evidence to be inconclusive and alternative explanations for the increased concentrations of coproporphyrin and zinc protoporphyrin are proposed.

ISSN:0269-3879    

DOI:10.1002/bmc.1130070102

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractAnalytical methods have been developed for the simultaneous quantitation of azelastine (AZ) and desmethylazelastine (DAZ) in guinea pig plasma and lung tissue. The methods require a 1.00 mL plasma sample and a minimum 0.100 g lung sample. Both methods employ liquid/liquid organic extraction and back‐extraction into dilute acid. Quantitation is performed by high performance liquid chromatography on a 2X250 mm 5 μm HypersilTMCPS column using fluroescence detection. The linear quantitative ranges for AZ.HCI and DAZ.HBr in plasma are 0.156–160 ng/mL and 0.313–160 ng/mL, respectively. The linear quantitative ranges for AZ.HCI and DAZ.HBr in lung tissue are 0.039–20 μg/g

ISSN:0269-3879    

DOI:10.1002/bmc.1130070103

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe diuretic drug hydrochlorothiazide (HCT) is used mainly for treatment of mild to moderate hypertension and is usually administered with other drugs. An assay for the determination of HCT in human plasma and urine by high performance liquid chromatography (HPLC) has been developed. Samples were purified by solvent extraction and analysed by reversed phase HPLC with ultraviolet detection, using hydroflumethiazide as the internal standard; plasma was eluted using gradient elution and urine was analysed isocratically. The method is simple to perform, is sensitive (detection limit 0.01 μg/mL in plasma and 0.2 μg/mL for urine); it showed good reproducibility (3–8%). A great number of drugs did not interfere with the assay and the method was used for pharmacokinetic studies in healthy subjects, but samples from patients can also be analysed with high selectiv

ISSN:0269-3879    

DOI:10.1002/bmc.1130070104

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractHydrophilic peptides generated from enzymic fragmentation of proteins are difficult to purify because they are either weakly bound or unretained by the reversed phase C18columns favoured for liquid chromatographic separation of peptide mixtures. To overcome this difficulty, peptides that were not bound or only weakly bound by a C18RP column were reacted with phenyl isothiocyanate (PITC), as used in the initial step in Edman sequencing. The hydrophobic phenylthiocarbamyl (PTC) peptide derivatives produced by the reaction were rechromatographed on the same column. Peptides generated by tryptic digestion of equine cytochrome C were used as a model system to test whether a complete set of peptide fragments could be purified by this method using just one column and solvent system. All the expected hydrophobic tryptic peptides bound to the RP column and were resolved by elution with acetonitrile, but no hydrophilic peptides were recovered as pure fractions. The column breakthrough fraction was reacted with PITC and rechromatographed on the same column, producing a profile consisting of 19 bound peaks. Further rechromatography of some of the fractions at different column temperatures enabled all six of the expected hydrophilic peptides to be purified and identified. The technique has also been applied to the sequence determination of coat protein from peanut stripe potyvirus protein, eight hydrophilic tryptic peptides being recovered and identified as PTC derivatives.

ISSN:0269-3879    

DOI:10.1002/bmc.1130070105

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractPropoxur (Baygon, 2‐isopropoxyphenylN‐methylcarbamate) is a carbamate pesticide commonly used against house insects. When the insecticide was administered intramuscularly in rats it was converted to a new metabolite which was found to be present in the serum, liver, kidney and brain 6 h after the administration of the pesticide. The metabolite was purified by high performance liquid to chromatography and comparison of the infrared spectra of Propoxur and the metabolite showed that a deamination reaction was responsible for the formation of the metabolite from the parent pesticide. The pesticide also induced haematological changes such as an increased level of total bilubrin, amylase and glutamic–oxalacetic transaminase and decrease of cholinesterase activity, indicating damage of the liver and nervous system in

ISSN:0269-3879    

DOI:10.1002/bmc.1130070106

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractA method is described for the determination of terbutaline and salbutamol in plasma from patients given maximal therapy for brittle asthma. The analytes were isolated by solid phase extraction on alkali‐treated Bond‐Elut, unmodified, silica columns and measured by high performance liquid chromatography with fluorescence detection (excitation wavelength 200 nm). The limits of detection for a 1 mL sample containing salbutamol and terbutaline were 1 μg/L and 2.5 μg/L, respectively. The intra‐assay precision (CV) for samples containing 25 μg/L was 3.6 and 5.0% respectively. This method was applied to the measurement of terbutaline in samples from patients given continuous infusions of the drug to assess whether this treatment might result in

ISSN:0269-3879    

DOI:10.1002/bmc.1130070107

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractA multidimensional column chromatographic method involving electrochemical detection using a carbon fibre microelectrode flow cell was optimized and successfully applied to the simultaneous determination of salbutamol and terbutaline in plasma at overdose levels. This method performs, in a single step, an efficient extraction and clean‐up of salbutamol and terbutaline from human plasma. The calibration graphs over three days were linear over the calibration range 20–100 ng/mL plasma with a limit of detection of 1 ng and 0.8 ng/mL plasma for salbutamol and terbutaline, respectively. The intra‐ and inter‐assay coefficients of variation were less than 8% and the recoveries ranged from 94 to 96%. The accuracy of the assay, which was defined as the percentage difference between the mean concentration found and the theoretical concentration, was 7% or better. The proposed method combines the advantages of being simple, reproducible and selective in the presence of other sympathomimetic and commonly ingested drugs and is suitable for routine analyses to obtain valuable information about the clinical effects and treatment of overdose with these drugs. The whole procedure takes ca. 10 min and compares favorably with detection at a conventional glassy carbon el

ISSN:0269-3879    

DOI:10.1002/bmc.1130070108

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractA rapid, sensitive and simple to operate high performance liquid chromatographic method for the simultaneous determination of morphine, morphine‐3‐glucuronide and morphine‐6‐glucuronide in plasma is described. The drug and its metabolites were extracted from plasma using commercially available reversed phase octylsilane bonded silica columns (1 mL Bond Elut C8, 50 mg). Chromatographic separation of morphine and its metabolites was achieved using a mobile phase, consisting of 2 mM sodium dodecyl sulphate in 0.05% phosphoric acid:acetonitrile (71.5:28.5 by volume), at a flow‐rate of 1.2 mL/min, in conjunction with a Waters Nova‐Pak C18 column (300 × 3.9 mm). The analytical column was used in combination with a Guard‐Pak module containing a Nova‐Pak C18 Guard‐Pak insert. Using fluorescence detection (excitation 245 nm, emission 335 nm), plasma levels in the region of 5–10 μg/L for the drug and its metabolites can be detected with only 200 μL of plasma. The method has been applied to studies of the disposition of morphine and its metabolites in premature neonates requiring mechanical ventilation who were receiving the drug intravenously; preliminary findings in patients at stea

ISSN:0269-3879    

DOI:10.1002/bmc.1130070109

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractA direct, isocratic and simple liquid chromatographic method is described for the enantiomeric separation of propafenone (PRO) and its major metabolite, 5‐hydroxypropafenone, using a cellulose tris‐3,5‐dimethylphenyl carbamate (Chiralcel ODS) column. The sterochemical separation factor (α) obtained was 1.14 and the maximum stereochemical resolution factor (R) was 0.80 when using a mobile phase consisting of hexane: 2‐propanol: diethylamine (90:10:0.4) at 23°C. The hydroxy metabolite could not be successfully separted into its corresponding enantiomers under these chromatographic conditions. The method has been used to determine and identify the enantiomers of PRO and its hydroxy metabolite in a ser

ISSN:0269-3879    

DOI:10.1002/bmc.1130070110

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY

摘要:

AbstractA simple high performance liquid chromatographic method combined with an enzyme sensor has been developed to measure 1,5‐anhydroglucitol in urine. The enzyme sensor consists of a hydrogen peroxide electrode and a chitosan membrane of an immobilized pyranose oxidase. As the system does not resist interfering substances, urine samples are first purified by passing them through a two‐layer column packed with (1) strongly basic anion (OH−form, the upper layer) and (2) strongly acidic (H+form, the lower layer) exchange resins. 1,5‐Anhydroglucitol is efficiently recovered in the flow‐through fraction of the column. In this system, the minimum detectable concentration of 1,5‐anhydroglucitol is 0.1 mg/L, and the measurable range extends from 0.1 to 60 mg/L. The coefficient of variation values of the within‐day and day‐to‐day precisions are 3.0‐6.5% and and 4.4‐6.7% respectively, and there is good agreement between the results measured by our method and those obtained by the gas‐liquid chromatographic/mass spectrometric method (r=0.994). The method we have described here has been successfully used to elucidate a mechanism for the reducing 1,5‐anhydroglucitol level in the ser

ISSN:0269-3879    

DOI:10.1002/bmc.1130070111

出版商:John Wiley&Sons, Ltd.    

年代:1993

数据来源: WILEY