Quantification of alprazolam in serum or plasma by liquid chromatography.

1984 ◽  
Vol 30 (10) ◽  
pp. 1652-1655 ◽  
Author(s):  
S R McCormick ◽  
J Nielsen ◽  
P Jatlow
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Isoamyl Alcohol ◽  
High Performance Liquid Chromatographic ◽  
Peak Height ◽  
Reversed Phase ◽  
Internal Standards ◽  
Steady State Serum ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A reversed-phase "high-performance" liquid-chromatographic assay for the quantification of alprazolam in serum or plasma is described. Serum or plasma is extracted with toluene/isoamyl alcohol (99/1 by vol), evaporated, and reconstituted in the mobile phase. The latter is washed with hexane, then subjected to reversed-phase liquid chromatography and ultraviolet detection at 202 nm. Either U-31485, an alprazolam analog, or lorazepam, a 3-hydroxybenzodiazepine, is satisfactory as internal standards. Major alprazolam metabolites and various other commonly used drugs do not interfere. The useful lower limit of sensitivity for quantification is 2.5 micrograms/L. Peak height and alprazolam concentration are linearly related from 2.5 to 100 micrograms/L. For 10 and 20 micrograms/L concentrations, within-run CVs were 1.4% and 0.9% and the between-runs CVs 4.8% and 3.2%. Steady-state serum concentrations ranged from 25 to 55 micrograms/L in patients taking 1.5 to 6.0 mg per day, orally. Preliminary data suggest the method is also suitable for analysis of the structurally similar triazolobenzodiazepine, triazolam.

Application of "high-performance" liquid chromatography to the study of sphingolipidoses.

1980 ◽  
Vol 26 (10) ◽  
pp. 1499-1503 ◽  
Author(s):  
M D Ullman ◽  
R E Pyeritz ◽  
H W Moser ◽  
D A Wenger ◽  
E H Kolodny
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Plasma Exchange ◽  
Chromatographic Analysis ◽  
High Performance ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Urine Sediment ◽  
Liquid Chromatographic Analysis ◽  
Liquid Chromatographic

Abstract Quantitative high-performance liquid chromatographic analysis of perbenzoylated sphingolipids has been used to study the correlations of body chemistry to clinical phenomena. Plasma sphingolipids were isolated from 32 Gaucher (β-glucosidase deficiency) and six Fabry (α-galactosidase deficiency) patients by solvent partition and chromatographic separation on silicic acid columns. Plasma sphingolipids from a patient undergoing plasma-exchange were separated from interfering lipids with reversed-phase columns. Liquid-chromatographic analysis of sphingolipids provides useful supportive information for diagnoses because affected individuals are shown to possess increased circulating concentrations of the pathognomonic sphingolipid. We also used this technique to monitor sphingolipid concentrations in plasma and urine sediment during plasma exchange of a p atient with Fabry’s disease. Regular plasma exchanges produced and maintained decreased concentrations of sphingolipids in plasma, but near pre-exchange concentrations were observed within days after the therapy was terminated.

Improved direct determination of alpha- and gamma-tocopherols in plasma and platelets by liquid chromatography, with fluorescence detection.

1982 ◽  
Vol 28 (8) ◽  
pp. 1784-1787 ◽  
Author(s):  
J Lehmann ◽  
H L Martin
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Limit Of Detection ◽  
Human Subjects ◽  
Direct Determination ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Liquid Chromatographic ◽  
Chloroform Methanol

Abstract Tocopherols extracted from plasma with methanol or from platelets with chloroform/methanol were injected in methanol on a reversed-phase (C18) "high-performance" liquid-chromatographic column and eluted with water/methanol (2/98, by vol) at a flow rate of 1.4 mL/min. A "high-performance" spectrophotofluorometer was used for detection. Analytical recoveries ranged from 89 to 106%. The response was linear to at least 0.3 micrograms of either tocopherol (alpha- or gamma-) applied to the column, and the limit of detection was 0.1 ng. The method was used to measure tocopherols in plasma and platelets from human subjects, and some values are presented.

scholarly journals Determination of Pantoprazole Sodium and Lansoprazole in Individual Tablet Dosage Forms by RP-HPLC Using Single Mobile Phase

2009 ◽  
Vol 6 (2) ◽  
pp. 489-494 ◽  
Author(s):  
B. Prasanna Kumar Reddy ◽  
Y. Ramanjaneya Reddy ◽  
D. Ramachandran
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Pharmaceutical Products ◽  
Liquid Chromatographic Method ◽  
Phase Liquid ◽  
Tablet Dosage ◽  
Liquid Chromatographic

A simple, sensitive and precise high performance liquid chromatographic method for the analysis of pantoprazole sodium and lansoprazole has been developed, validated and used for the determination of compounds in commercial pharmaceutical products. The compounds were well separated an isocratically on a C18column [Inertsil C18, 5μ, 150 mm x 4.6 mm] utilizing a mobile phase consisting of acetonitrile: phosphate buffer (60:40, v/v, pH 7.0) at a flow rate of 1.0 mL/min with UV detection at 230 nm. The retention time of pantoprazole sodium and lansoprazole was found to be 2.017 min and 2.538. The procedure was validated for linearity (Correlation coefficient=0.999). The study showed that reversed-phase liquid chromatography is sensitive and selective for the determination of pantoprazole sodium and lansoprazole using single mobile phase.

Determination of urinary glyoxal and methylglyoxal by high-performance liquid chromatography

2004 ◽  
Vol 42 (2) ◽  
Author(s):  
Kazuki Akira ◽  
Yui Matsumoto ◽  
Takao Hashimoto
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Carbonyl Stress ◽  
Age Related ◽  
Highperformance Liquid Chromatography ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic

AbstractCarbonyl stress compounds such as glyoxal and methylglyoxal have been recently attracting much attention because of their possible clinical significance in chronic and age-related diseases. A high-performance liquid chromatographic procedure has been developed for the simultaneous quantitation of glyoxal and methylglyoxal in human urine. The assay is based on the reaction of these compounds with 1,2-diamino-4,5-dimethoxybenzene to form fluorescent adducts, which are separated by reversed-phase highperformance liquid chromatography in a total run time of 45 minutes and quantitated fluorometrically using 2,3-pentanedione as an internal standard. Derivatization is performed for diluted urine (100–120 mOsm/kg H

scholarly journals Development and Validation of a Column High-Performance Liquid Chromatographic Method for Determination of Sibutramine in Capsules

2009 ◽  
Vol 92 (1) ◽  
pp. 148-151 ◽  
Author(s):  
Isabel Cristina Fração Diefenbach ◽  
Milene Friedrich ◽  
Marcos Roberto Dos Santos ◽  
Celso Figueiredo Bittencourt
Keyword(s):  
High Performance ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Control Analysis ◽  
Constant Flow Rate ◽  
Relative Standard ◽  
Phase Liquid ◽  
Development And Validation ◽  
Liquid Chromatographic

Abstract The development and validation of a reversed-phase liquid chromatographic (LC) method for the determination of sibutramine hydrochloride monohydrate in capsules is described. An isocratic LC analysis was performed on a reversed-phase RP-18 column (250 4.6 mm id, 5 m particle size). The mobile phase consisted of methanolwatertriethylamine (80 + 20 + 0.5, v/v/v), with pH adjusted to 5.65 with 85 phosphoric acid, and was pumped at a constant flow rate of 1.0 mL/min. Measurements were made at a wavelength of 223 nm. The calibration curve was linear over the range of 1540 g/mL [correlation coefficient (r2) = 0.9998]. The relative standard deviation (RSD) value for intraday precision was 0.84. The RSD value for interday precision was 0.90. Recoveries ranged from 99.64 to 100.66. No interferences from the excipients were observed. Because of its simplicity and accuracy, the method is suitable for routine quality control analysis of sibutramine in capsules.

scholarly journals Simultaneous Determination of Piracetam and Vincamine by Spectrophotometric and High-Performance Liquid Chromatographic Methods

2008 ◽  
Vol 91 (2) ◽  
pp. 311-321 ◽  
Author(s):  
Yasser Shaker Ibrahim El-Saharty
Keyword(s):  
High Performance ◽  
Pharmaceutical Preparation ◽  
Standard Addition ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Potassium Dihydrogen ◽  
Accuracy And Precision ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A mixture of piracetam and vincamine was determined by 3 different methods. The first was the determination of piracetam and vincamine using the ratio-spectra first-derivative (DD1) spectrophotometric technique at 209 and 293 nm in concentration ranges of 1045 and 214 g/mL with mean recoveries of 99.22 0.72 and 99.67 0.79, respectively. The second method was based on the resolution of the 2 components by bivariate calibration depending on a mathematic algorithm that provides simplicity and rapidity. The method depended on quantitative evaluation of the absorbencies at 210 and 225 nm in concentration ranges of 545 and 214 g/mL, with mean recoveries of 100.33 0.54 and 100.44 0.98 for piracetam and vincamine, respectively. The third method was reversed-phase liquid chromatography using 0.05 M potassium dihydrogen phosphatemethanol (50 + 50, v/v) as the mobile phase, with the pH adjusted to 3.5 with phosphoric acid. The eluent was monitored at 215 nm in concentration ranges of 5100 and 2200 g/mL, with mean recoveries of 99.62 0.67 and 99.32 0.85 for piracetam and vincamine, respectively. The suggested procedures were checked using laboratory-prepared mixtures and were successfully applied for the analysis of their pharmaceutical preparation. The methods retained their accuracy and precision when applying the standard addition technique. The results obtained by applying the proposed methods were statistically analyzed and compared with those obtained by the manufacturer's method.

Determination of serum alpha-tocopherol (vitamin E) by high-performance liquid chromatography.

1978 ◽  
Vol 24 (4) ◽  
pp. 585-590 ◽  
Author(s):  
A P De Leenheer ◽  
V O De Bevere ◽  
A A Cruyl ◽  
A E Claeys
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Alpha Tocopherol ◽  
Gas Chromatography Mass Spectrometry ◽  
Gas Liquid Chromatography ◽  
Total Analysis ◽  
Liquid Chromatographic

Abstract We report a fast, simple high-performance liquid-chromatographic assay for serum alpha-tocopherol, with use of a reversed-phase column and tocol as internal standard. Only 200 microliter of serum is required. Isocratic elution of the n-hexane extract is done within 6 min; total analysis time is less than 1 h. Within-day precision (CV) was 2.3% for 24 samples of a normal plasma pool (mean concn, 10.1 mg/liter). Day-to-day precision (CV) was 3.2%, measured for 20 days for a specimen with a concentration of 10.8 mg/liter. Analytical recovery of alpha-tocopherol from fortified serum was 89 to 100%. The lower detection limit of alpha-tocopherol is estimated to be 0.6 mg/liter. The specificity of the procedure was verified by spectrophotometry, gas-liquid chromatography, and combined gas chromatography/mass spectrometry of an eluate collected from the column.

Reversed-phase liquid chromatographic separation of 3',5'-cyclic ribonucleotides.

1979 ◽  
Vol 25 (2) ◽  
pp. 235-241 ◽  
Author(s):  
A M Krstulovic ◽  
R A Hartwick ◽  
P R Brown
Keyword(s):  
Chromatographic Separation ◽  
High Performance ◽  
Peak Shift ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Liquid Chromatographic Separation ◽  
Biological Extracts ◽  
Phase Liquid ◽  
Chromatographic Peaks ◽  
Liquid Chromatographic

Abstract A rapid, reversed-phase "high-performance" liquid-chromatographic separation of the five naturally occurring cyclic ribonucleotides is described. The separation, optimized for the measurement of these compounds in biological samples, is short (25 min), sensitive (50-100 pmol), and requires no sample pre-concentration steps. We also report an alternative isocratic elution mode, optimized for a rapid and selective analysis for adenosine 3',5'-cyclic phosphate. The identity of chromatographic peaks in biological extracts is confirmed by several methods: retention times, co-chromatography with the reference compounds, absorbance ratios, enzymatic peak-shift with cyclic nucleotide phosphodiesterase, and stopped-flow ultraviolet-scanning techniques.

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