Rapid and sensitive electron-capture gas chromatographic method for the determination of pinazepam and its metabolites in human plasma, urine and milk.

A rapid, sensitive and specific gas-liquid chromatographic method for the measurement of pinazepam and its metabolites in biological fluids is reported. After a single extraction of the sample with toluene, the organic phase is concentrated and, after chromatography on a 3% OV-17 column, measured with an electron-capture detector. The sensitivity was 1.0 ng/ml for pinazepam and 5.0 ng/ml for its metabolites. Plasma levels and urinary excretion in human volunteers and plasma and milk levels in women suffering from anxiety during breastfeeding are reported.     

High-performance liquid chromatographic method for simple and rapid determination of linezolid in human plasma

A simple high-performance liquid chromatographic (HPLC) method was developed and validated for rapid quantification of linezolid in human plasma. Protein precipitation using a mixture of 5% trichloroacetic acid and methanol (3:1, v/v) provided a straightforward method of sample preparation and the internal standard eperezolid was employed. A concentration range from 0.20 to 40.0 mg/L was utilized to construct calibration curves, and analysis of low- (0.40 mg/L), medium- (7.50 mg/L) and high-quality (25.0 mg/L) control samples revealed excellent reproducibility (相似文献   

A rapid gas chromatographic method for the determination of chlorophenoxyisobutyric acid in plasma and urine.

A rapid gas chromatographic method is described for the determination of chlorophenoxyisobutyric acid (the active metabolite of clofibrate) in plasma and urine. The assay involves an extraction into toluene and back-extraction of the chlorophenoxyisobutyric acid and the internal standard (2-naphthoic acid) into the methylating reagent (trimethylanilinium hydroxide). Concentrations of 1 mug/ml in plasma and urine can easily be measured; the precision of the method is 3.3 +/- 0.7% for plasma and 2.7 +/- 0.4% for urine. There is no interference from endogenous compounds or from drugs commonly prescribed together with clofibrate.     

Gas chromatographic method for the determination of nomifensine in human plasma.

An analytical method based on solvent extraction, formation of a fluorinated derivative and quantitation by gas-liquid chromatography using an electron capture detector has been developed for the determination of nomifensine in biological fluids. The specificity (controlled by mass spectrometry) and the sensitivity appear to be satisfactory for drug level measurements in human body fluids. Its relative simplicity in fact permits its use in serial analysis.     

A simple, sensitive liquid chromatographic method for quantitation of D-galactose and D-glucose in blood plasma

The concentrations of D-glucose and D-galactose in plasma of galactosemic rats were quantitatively measured by a liquid chromatographic method, based on retention of the weakly ionized monosaccharides by an anion exchange column under alkaline conditions, elution with 9 mmol/L NaOH, and electrochemical detection. This method is both simple and sensitive, since very dilute plasma samples can be directly analysed.     

Simple and sensitive high-performance liquid chromatographic method for the determination of diltiazem and six of its metabolites in human plasma.

A sensitive, specific and reproducible high-performance liquid chromatographic technique is described for the simultaneous determination in human plasma of diltiazem (DZ) and six of its primary and secondary metabolites which are products of N- and O-demethylation, deacetylation and N-oxidation. The method involves addition of excess KHCO3 to 1 ml of plasma, followed by extraction with 4 ml of ethyl acetate. The organic layer was extracted with 0.01 M HCl and the aqueous layer was dried under nitrogen and then reconstituted with 0.002 M HCl. DZ and its metabolites were free from interference and wer baseline-separated. Calibration curves were linear in the concentration range studied (5-500 ng/ml for all the species). The lower limit of quantification of the assay was 5 ng/ml for DZ and the metabolites. Inter-day and intra-day coefficients of variation were less than 10%. The applicability of this procedure is shown by evaluating the kinetics of DZ and its metabolites in three patients receiving chronic DZ therapy. N-Demethyldiltiazem, deacetyldiltiazem and N-demethyldeacetyldiltiazem were found to be the major metabolites, as previously described. Deacetyldiltiazem N-oxide was found in two of the patients. The other two known but unreported metabolites in human, O-demethyldeacetyldiltiazem and N,O-didemethyldeacetyldiltiazem, were found in the plasma of all three patients.     

A simple procedure for the chromatographic isolation and determination of prostaglandins from human seminal plasma

Summary A relatively simple procedure for the isolation and determination of the prostaglandins present in human seminal fluid is described. It involves preliminary chromatographic purification of these compounds from the major non-prostaglandin impurities followed by their total elution in one solvent (one-step elution). The prostaglandins thus obtained were almost free from other lipids and were further resolved into prostaglandin-groups and individual prostaglandins by repeated thin-layer chromatography. Data are also presented for prostaglandin contents of fresh semen samples from five individuals and results compared with those from the stored samples.

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Einfaches Verfahren zur chromatographischen Isolierung und Bestimmung von Prostaglandinen aus menschlichem Sperma

Zusammenfassung Das Verfahren umfaßt eine chromatographische Abtrennung der Verbindungen von den hauptsächlichsten Verunreinigungen und die Gesamtelution mit einem Lösungsmittel. Die von anderen Lipiden fast völlig freien Prostaglandine werden durch wiederholte Dünnschicht-Chromatographie in Gruppen und Einzelverbindungen getrennt. Werte werden angegeben über die Prostaglandingehalte von frischem im Vergleich zu gelagertem Sperma.

     

Capillary gas chromatographic method for the determination of the thromboxane A2 receptor antagonist S-1452 and its metabolites in human plasma.

A capillary gas chromatographic method for the determination of a newly developed thromboxane A2 antagonist, S-1452, and its metabolites in human plasma has been developed. This nitrogenous compound was detected as the free acid (+)-S-145 using a nitrogen-phosphorus detector. The two metabolites bisnor-(+)-S-145 and tetranor-(+)-145 were also assayed. The three compounds, which all possess carboxylic acid group, were converted into their hexafluoro-2-propyl esters with hexafluoropropan-2-ol-pentafluoropropionic anhydride as reagent. The esterification resulted in a decreased background response from the detector, and hence higher sensitivity and better precision. The glucuronides of the three compounds were also assayed after alkaline hydrolysis. The plasma concentration of the glucuronide of I was more than twice that of the free acid. This method allows determination of the three compounds at more than 2 ng/ml with a precision of 2-6% and an accuracy variation of less than +/- 5%. The analysis was performed within 2 min after injection to assay the sample rapidly from the Phase I test. The method is suitable for pharmacokinetic studies.