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  • Column liquid chromatography  (51)
  • pharmacokinetics  (31)
  • Springer  (82)
  • American Association of Petroleum Geologists
  • Frontiers Media SA
  • Institute of Physics
  • Wiley
  • 2020-2024
  • 2010-2014
  • 1995-1999  (82)
  • 1920-1924
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  • Springer  (82)
  • American Association of Petroleum Geologists
  • Frontiers Media SA
  • Institute of Physics
  • Wiley
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Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 44 (1997), S. 257-262 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Microchromatography ; Raman spectroscopy ; Deuterated solvents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A detector for microchromatography in which Raman spectroscopy is used to identify the eluted species has been developed. The detector is designed to be applicable to a wide range of compounds without requiring the presence of a chromophore. Its use is illustrated in the analysis of nitro compounds on a 250 μm i.d. column. Raman spectra of each of the compounds could be identified as they passed the detector. The advatages of the use of fully deuterated solvents are demonstrated by the analysis of nitrobenzenes in methanol/water mobile phases. The detection limit for nitrobenzene using the Raman line at 1342 cm−1 was 75ng.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 48 (1995), S. 273-277 
    ISSN: 1432-1041
    Keywords: Mesalamine ; 5-aminosalicylic acid ; controlled release capsules ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract One gram single dose of Pentasa controlled-release capsules was administered to 24 healthy volunteers under fasting condition. Mean plasma 5-aminosalicylic acid (5-ASA) and acetyl 5-ASA concentrations peaked at 0.53 μg · ml−1 and 1.33 μg · ml−1 from 3 to 4 hours following dosing, respectively. The half-lives of both compounds could not be determined as absorption of 5-ASA was continuous throughout the gastrointestinal tract. An average of 29.4% (CV: 27%) of the dose was excreted in the urine primarily as acetyl 5-ASA. Up to 91.1% of the dose was released from the capsules. Forty percent of the dose (CV: 40%) was eliminated in the feces, with 8.9% of the dose remained as formulation bounded 5-ASA, indicating that controlled-release capsules continue to release drug throughout the GI tract. 5-ASA contributed 46.7% of the salicylates eliminated in the feces and acetyl 5-ASA accounted for the balance. Controlled-release capsules produced three times more total salicylates and 10 times more total and free 5-ASA in the feces than did 5-ASA suspension. Thus, while lower systemic levels of salicylates were absorbed, greater therapeutic quantities of 5-ASA were available in the bowel.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-0646
    Keywords: phase I ; brequinar ; DUP 785 ; cisplatin ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Brequinar (DUP 785; NSC 368390) is a quinoline carboxylic acid derivative that inhibits pyrimidine synthesis at the level of dihydro-orotate dehydrogenase and revealed synergy with cisplatin in preclinical models. In this study investigating the pharmacokinetic and toxicity of brequinar in combination with cisplatin, patients were initially treated with weekly brequinar, in combination with an every-three-week administration of cisplatin. Due to toxicity, the schedule was modified to a 28-day cycle with brequinar given on days 1, 8, 15, and cisplatin on day 1. A total of 24 patients (16 male, 8 female; median age 57; median performance status 1) received 69 courses of therapy. Six dose levels were explored, with cisplatin/ brequinar doses, respectively, of 50/500, 50/650, 50/860, 60/860, 75/650, and 75/860 mg/m2. The serum concentration versus time curves for brequinar were biphasic. A comparison of the pharmacokinetic results after the first and third doses of brequinar indicate that the presence of 50, 60, and 75 mg/m2cisplatin did not change the protein binding and the pharmacokinetics of brequinar in any of the three brequinar-dose groups. Total cisplatin plasma pharmacokinetic followed a triphasic-shape curve and unbound cisplatin decayed at a very rapid rate. Since pharmacokinetic parameters for total cisplatin in this study were similar to those reported in the literature, the presence of brequinar is unlikely to alter the pharmacokinetics of cisplatin. Main dose-limiting toxicities included myelosuppression (including neutropenia and thrombocytopenia) and mucositis. Cisplatin/brequinar doses of 50/500, 50/650, 50/860, 60/860, 75/650, and 75/860 mg/m2, were associated with dose limiting toxicity in 0/3, 1/3, 1/3, 1/3, 2/4, 2/5, and 4/6 patients, respectively. This study shows that co-administration of brequinar and cisplatin does not affect the pharmacokinetic properties of either drug and that the MTDs of cisplatin/brequinar combinations are 60/860 mg/m2 or 75/650 mg/m2. From this study, we conclude that full dose of 75 mg/m2 cisplatin (day 1) can be administered with 650 mg/m2 brequinar (days 1, 8 and 15) without significant modifications of individual drug pharmacokinetic parameters.
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  • 4
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Porous graphitic carbon ; Optimization ; Morphine and metabolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The chromatographic behaviour of a series of morphine-based opiates has been investigated using a porous graphitic carbon packing material at acid and alkaline pH. The effects of mobile phase pH, mobile phase organic percentage, column temperature and ionpairing agents were studied. All six opiates were separated within a close retention window despite large differences in measured lipophilicities of the individual opiates. The retention order was not related to the log P values of the opiates and strong retention of the fully ionised compounds was observed, particularly those with acidic functional groups. The effect of pH on the retention of the compounds indicated that the degree of ionisation of the individual compounds was important in the separation mechanism, suggesting that hydrophobic interactions were present in addition to the polar retentive effects observed above. The strong retention of the ionised glucuronide and sulphate conjugates of morphine is a particularly useful feature of the porous graphitic carbon packing material which has general applicability to the analysis of polar or ionised drug metabolites.
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  • 5
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Pharmaceutical formulations ; Triprolidine ; Pseudoephedrine ; Paracetamol ; Dextromethorphan
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple, rapid and specific HPLC method has been developed for the determination of triprolidine, pseudoephedrine, paracetamol and dextromethorphan, in combination, in different pharmaceutical dosage forms, using a reversed-phase C18 column, gradient elution, and UV detection at 254 and 280 nm. No preliminary extraction procedure is required for liquid formulations and a very simple extraction procedure is required for tablets and creams. The recovery of the drugs ranged from 96.0 to 98.7%. The assay results obtained for eight commercially available formulations were in agreement with the amounts declared. The linearity and precision of the method have been assessed.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 44 (1997), S. 619-622 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Boldine in pharmaceuticals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method is proposed for extraction, separation, identification and quantitative measurement of boldine (I) in pharmaceuticals. The extraction of (I) from the matrix (syrups, tablets, extracts) was realized with aqueous ammonium chloride (0.02 M, pH=3.0 with perchloric acid) and the clean-up of the extract was performed by solid-phase extraction by means of cartridges containing a strong cation-exchange sorbent, from which (I) was eluted with aqueous ammonium chloride (1 M, pH=10.0 with ammonia). The final eluate was examined by HPLC. Chromatography was performed on a C-8 column with a gradient elution from 15:85 to 30:70 of acetonitrile-water containing 0.1 M sodium perchlorate (pH=3.0), in 20 min. A diode array detector was used at 302 nm for detection. The method gives recovery values greater than 98% and the reproducibility is within 6.0%.
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  • 7
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Solid phase extraction ; Enzyme-based biosensor detection ; Tyrosinase ; Phenols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A fully integrated screening system for phenolic compounds was developed incorporating on-line solid phase extraction, fractionation and biosensor detection. Two different types of biosensors, solid graphite and carbon paste electrodes incorporating the enzyme tyrosinase, were compared and used in the screening system. Interfacing of the solid phase extraction and fractionation with the biosensor detection was given special attention since the biosensors were not compatible with the organic modifier used for desorption of phenols from the solid phase extraction step. The system was validated with conventional analytical techniques. Surface water samples from the Ebro river were spiked with 1,10, and 25μg L−1 of catechol, phenol,p-cresol, respectively. Three out of seven samples were spiked and the correct samples were identified, containing phenols equivalent to the spiked concentrations.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 43 (1996), S. 76-78 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Rhodamine B in cosmetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method is proposed for the extraction, separation, identification and quantitative measurement of rhodamine B in cosmetics samples The colour is extracted with a solution of orthophosphoric acid in either water or DMF (depending on the type of cosmetic) adsorbed on a polyamide column, and then eluted with water and methanol. Further clean-up of the extract is performed by means of a Bond Elut C-18 cartridge, from which rhodamine B is eluted with methanol-water (8∶2). The final eluate is examined by HPLC. Chromatography is performed on a C-18 column with a gradient elution from 50∶50 to 70∶30 of acetonitrile-water, containing 0.1 M sodium perchlorate, in 15 min. A diodearray detector enables peak purity analysis. The method gives recovery values of approximately 90%, or better, and the reproducibility is within 4%.
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  • 9
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gas chromatography ; Enantiomeric separation ; Chiral derivatization ; Unusual secondary aromatic amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary High-performance liquid chromatographic and gas chromatographic methods were developed for the separation of unusual secondary aromatic amino acids. Amino acids containing 1,2,3,4-tetrahydroisoquinoline, 1,2,3,4-tetrahydronorharmane-1-carboxylic acid and 1,2,3,4-tetrahydro-3-carboxy-2-carboline moieties were synthetized in racemic or chiral forms. The high-performance liquid chromatography was carried out either on a teicoplanin-containing chiral stationary phase or on an achiral C18 column. In the latter case the diastereomers of the amino acids formed by precolumn derivatization with the chiral reagents 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl isothiocyanate or 1-fluoro-2,4-dinitrophenyl-5-L-alanine amide were separated. The gas chromatographic analyses were based on separation on a Chirasil-L-Val column.
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  • 10
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; NMR spectroscopy and mass spectrometry ; Plant products ; Silene otites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary HPLC coupled in parallel to nuclear magnetic resonance (NMR) and mass spectrometry (MS) has been used to obtain1H NMR and mass spectra of a number of ecdysteroids present in an extract of the plantSilene otites. Reversed phase gradient chromatography was performed using a D20-acetonitrile-based solvent system. NMR and mass spectra were obtained for integristerone A, 20-hydroxyecdysone, 2-deoxy-20-hydroxyecdysone and 2-deoxyecdysone to provide structural confirmation using continuous and stopped flow HPLC-NMR. The combined HPLC-NMR-MS system described here provided a more comprehensive analysis of the ecdysteroids present in the extract than HPLC-NMR alone.
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