摘要:

Polystyrene-block-poly(methyl methacrylate) micelles in 1,4-dioxane/cyclohexane were studied by size exclusion chromatography coupled with multi angle light scattering (SEC/MALS). A sufficient unimer — micelles resolution achieved by SEC made it possible to use MALS detector for the direct determination of distributions and corresponding averages of molecular weights and gyration radii of micelles.

ISSN:1082-6076    

DOI:10.1081/JLC-100101788

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A sensitive and selective method for the determination of 1-(((7,7-dimethyl-2(S)-(2(S)-amino-4-(methylsulfonyl) butyramido)-bicyclo[2.2.1]-heptan-1(S)-yl) methyl) sulfonyl) - 4 - (2 - methyl-phenyl)-piperazine (L-368,899) in human plasma is described. The method is based on liquid-liquid extraction followed by automated pre-column chemical derivatization of the primary amino group of the drug and an internal standard with 2,3-naphthalene dicarboxaldehyde and N-acetylcysteamine to form fluorescent benzo[f]isoindole derivatives.

ISSN:1082-6076    

DOI:10.1081/JLC-100101789

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The partition coefficients, logPoctapp, for a series of propranolol analogues have been obtained by reversed phase-high performance liquid chromatography (RP-HPLC). A Collander type equation was set for 22 different standards that have the same trend as their H-bond capability. Fluorinated propranolol analogues are known to possess enhanced pharmacological properties and thus they were also investigated according to their capability offorming H–bonding.

ISSN:1082-6076    

DOI:10.1081/JLC-100101790

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The stability constants (KML) of Cu(II), Co(II), Zn(II), Ni(II), and Mn(II) chelates with 3, 8, 13, 18 -tetrametyl-21H, 23H-porphine -2,7,12,17- tetrapropionic acid, or coproporphyrin-I (CPI) have been determined by reversed-phase high performance liquid chromatography (RP-HPLC) on a octadecyl-bonded silica gel (C18silica) with developing solvent (69:31 v/v) methanol-buffer at pH 7 (buffer ionic strength 0.270 mol L−1: 0.018 mol L−1boric, phosphoric and acetic acid, and 0.036 mol L−1sodium hydroxide), and 0.050 mol L−1of NaCl, with UV detection.

ISSN:1082-6076    

DOI:10.1081/JLC-100101791

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A micellar electrokinetic chromatography (MEKC) method was developed to analyze acetaminophen (AP),caffeine (CF), and butalbital (BB) simultaneously in a commercial tablet dosage form. Uncoated fused silica capillary (70 cm × 50 μm i.d, 50 cm to detector) was used for the separation at an applied voltage of 20 kV. A phosphate run buffer (pH 9, 0.05 M) containing 0.05 M sodium dodecyl sulphate was used for analysis. Separations of the analytes were achieved within 12 min at ambient temperature with detection set at 220 nm. Calibration curves were prepared for AP (260-520 μg/mL), CF (30–64 μg/mL) and BB (40–80 μg/mL) by the internal standard method with methyl–p–hydroxybenzoate as internal standard. Correlation coefficients of calibration curves were greater than 0.990. A five second hydrodynamic injection was used for analysis. Tablet powder equivalent to one tablet weight was extracted with absolute methanol in an ultrasonic bath for 30 min. The methanol extract was diluted with water and injected into the CE system for quantitation. Recoveries of the analytes were in the 95–103% range.

ISSN:1082-6076    

DOI:10.1081/JLC-100101792

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Understanding the process of biological molecule-protein binding in the body is very important. A model system for the application of capillary electrophoresis in the measurement of the binding constants of porphyrin-protein is discussed. The results are described, demonstrating that capillary electrophoresis can be employed as a rapid screening tool for investigating the binding of different forms of porphyrin to a protein.

ISSN:1082-6076    

DOI:10.1081/JLC-100101793

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

An isocratic and simple high performance liquid chromatographic method was developed for the direct resolution of clenbuterol enantiomers. The method involved the use of the macrocyclic antibiotic teicoplanin chiral stationary phase column known as Chirobiotic T. Several mobile phase compositions were studied to optimize the resolution of racemic clenbuterol. The role of using different solvents, e.g. methanol, ethanol, and acetonitrile as organic modifiers and the effect of triethylamine and acetic acid on the enantioseparation of clenbuterol were investigated.

ISSN:1082-6076    

DOI:10.1081/JLC-100101794

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

An HPLC method was developed and subsequently validated for the quantitation of cromolyn sodium and its related substances in cromolyn sodium drug substance and Cromolyn Sodium Inhalation Solution, 1.0%. The current USP monograph for cromolyn sodium assay is a non–selective UV method while related substances are determined by TLC. The TLC method, as written in the USP, does not meet the sensitivity requirements as dictated by current regulations. The HPLC method described in this paper provides more accurate and selective quantitation of cromolyn sodium and its two known potential impurities, cromolyn diethyl ester (Impurity 1) and hydroxy phenoxy 2-propanol (Impurity 2). The method development involved the evaluation of several factors including mobile phase composition, column choice and configuration, wavelength evaluation, and response factors.

ISSN:1082-6076    

DOI:10.1081/JLC-100101795

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A sensitive and a rapid procedure is described using high performance liquid chromatography combined with electro-chemical detection (HPLC-ECD), for quantification of whole blood biogenic amines and their metabolites. Serotonin (5-hydroxytryptamine, 5-HT), its precursor 5-hydroxytryptophan (5-HTRP), and metabolite 5-hydroxyindoleacetic acid (5-HIAA), dopamine (DA) and its metabolite homovanillic acid (HVA), were extracted from an aliquot of whole blood.

ISSN:1082-6076    

DOI:10.1081/JLC-100101796

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A stability-indicating High Performance Liquid Chromato-graphy (HPLC) method utilizing nonporous silica particle technology has been developed for the assay of meropenem and ofloxacin from 5% dextrose in water injection USP and 0.9% sodium chloride injection USP. The separation and quantitation of the mixture were achieved on a column packed with nonporous silica particles chemically bonded with octadecylsilane (3.0 (μm particles) using a mobile phase of 94:6 v/v 15 mM potassium dihydrogen phosphate buffer (pH 2.7)-methanol at a flow rate of 0.6 mL/min with UV detection at 270 nm. The separation was achieved in less than 4 min. Meropenem and ofloxacin were subjected to acid, base, peroxide, and ultraviolet degradation and monitored using photodiode detection. None of the products of degradation showed any interference with the peaks of interest. Standard curves were prepared and correlation coefficients were ≥ 0.999 for both compounds.

ISSN:1082-6076    

DOI:10.1081/JLC-100101797

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor