Separation of organic amine compounds on silica gel with reversed-phase eluents

Bidlingmeyer, Brian A.; Rios, John K. Del; Korpi, J.

doi:10.1021/ac00240a021

Cited by 212 publications

(59 citation statements)

References 22 publications

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“…Chromatographic retention on bare silica using aqueous-organic mobile phase involves hydrophilic interaction, ionexchange, and hydrophobic retention [14,16,18]. The relative strength of various adsorption forces depends on the composition of the mobile phase.…”

Section: Resultsmentioning

confidence: 99%

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Effect of temperature on the chromatographic behavior of epirubicin and its analogues on high purity silica using reversed-phase solvents

DONG¹,

HUANGL²

2007

Chromatographia

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The influence of temperature on the retention behavior of epirubicin and its analogues on high purity silica with reversed-phase solvents has been systematically investigated. It was found that temperature effects on retention are highly dependent on the type and concentration of organic modifier, as well as the pH of the mobile phase. In organic-rich mobile phases, the type of organic modifier plays an important role. With an aprotic solvent as modifier, retention times show anomalous increases with elevated temperature. At the same time, both efficiency and resolution are significantly improved but this is not the situation with a protic solvent as modifier. In addition, temperature shows different effects on retention time and selectivity when the pH is changed, and temperature-dependent selectivity reversal is found at higher pHs. In aqueousrich mobile phases, regardless of the nature of the organic solvent and pH, retention of solutes drops as temperature is raised. It seems that the effect of temperature on chromatographic behavior of the solutes on bare silica using mobile phases containing various organic modifiers or pHs, results from a number of different retention mechanisms.

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Section: Resultsmentioning

confidence: 99%

“…Basic compounds can be separated on bare silica with aqueous-rich mobile phases [12,13] or with organic-rich eluents [14,15]. The effects of temperature on the retention behavior of small compounds on bare silica at certain compositions of aqueous-organic mobile phases has been reported [16,17].…”

Section: Introductionmentioning

confidence: 99%

Effect of temperature on the chromatographic behavior of epirubicin and its analogues on high purity silica using reversed-phase solvents

DONG¹,

HUANGL²

2007

Chromatographia

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“…However, recent studies (1) show that the optimization of conditions is possible with silica gel and acidic aqueous solvent systems such as those used in reverse-phase chromatography. This has been done for the clinical application of the chromatography of plasma lidocaine and its derivatives (2).…”

Section: Discussionmentioning

confidence: 99%

Determination of pipemidic acid in plasma by normal-phase high-pressure liquid chromatography

Ito¹,

Inoue²,

Morikawa³

et al. 1985

Antimicrob Agents Chemother

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An improved high-pressure liquid chromatography procedure for determining the concentration of pipemidic acid in human plasma was developed, which uses a normal-phase silica gel column and aqueous mobile solvent system similar to that used in reverse-phase chromatography. Precolumn derivatization of pipemidic acid was achieved by a methylation reaction with boron trifluoride in methanol after extraction from plasma with chloroform containing 4% ethanol. The percent recovery of pipemidic acid was 88.3 7.7, the variation of which became negligible when quinacrine was used as an internal standard for the determination. High-pressure liquid chromatography analysis was performed by conventional silica gel and mobile solvent mixtures containing 3% of 0.14% HCl04 solution, 19% methanol, and 78% chloroform. The UV detector was set at 265 nm. The detection limit of pipemidic acid methyl ester was as low as 10 ng of the injection amounts or 0.5 ,ug of the plasma per ml, with 0.01 absorbance units (full scale) and a signal-to-noise ratio of 3.In the past decade, pipemidic acid (4) has been found to possess higher antibacterial activity against Pseudomonas aeruginosa, Escherichia coli, Proteus vulgaris, Klebsiella pneumoniae, and Enterobacter and Citrobacter organisms (5, 12-14) than structurally similar agents, such as piromidic (11) and nalidixic acid (3), and thus has been applied to chemotherapy of parenchymatous urinary tract infections. The known chronic and acute toxicities of pipemidic acid are rather low (6-9); however, numerous pharmacokinetic studies have been conducted to determine the most effective concentrations in serum for clinical use. In 1975, Japanese workers (10) recommended a biological assay technique that uses the thin-layer cup plate of E. coli Kp strain as an indicator organism. More recently, French workers (M. Le Duff, D. Gibassier, P. A. Sado, and R. Le Verge, Abstr. C. R. Congr. Eur. Biopharm. Pharmacokinet. 1st, series 2, p. [508][509][510][511][512][513][514][515] 1981) have reported a high-pressure liquid chromatography procedure for determining the concentration of pipemidic acid in rabbit plasma. Since pipemidic acid has a very strong basic moiety in its molecular structure, conventional chromatographic procedures would not be adequate for pharmacological studies. This paper presents a new chromatographic technique which uses a silica gel (stationary phase) and reversed mobile-phase solvents for accurately determining pipemidic acid content in human plasma.MATERIALS AND METHODS Extraction and precolumn derivatization. A 2-ml plasma specimen was spiked with 20 ,ug of quinacrine per 20 ,ul of methanol solution, and the resulting mixture was acidified to ca. pH 4.5 with 100 ,ul of 2 N hydrochloric acid. Neutral and acidic contaminants were eliminated by washing the mixture with 2 ml of chloroform in a 10-ml test tube with a vortex mixer. The organic layer was eliminated, and the aqueous layer was diluted with 1 ml of distilled water. The aqueous mixture was adjusted at ca. pH 7.0 with 2 N so...

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“…Such a mechanism also retains considerable amounts of other lipophilic substances, thereby interfering with the drug peak. On the other hand, in a system consisting of a bare silica gel and an aqueous mobile phase, the retention mechanism results mainly from ion exchange 20 and only partially from lipophilic interactions. Thus, endogenous non-ionic neutral lipid compounds and anionic compounds will not be retained on the silica gel column; only the cationic (e.g.…”

Section: Study Descriptionmentioning

confidence: 99%

Analysis of Investigational Drugs in Biological Fluids - Method Development and Routine Assay

Lin¹,

Benet²,

Upton³

et al. 1991

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Emil T. Lin PERFORMING ORGANIZATION NAME(S) AND ADORESS(ES) S.PERFORMING ORGANIZATIONSchool of Pharmacy REPORT NUMBERUniversity of California San Francisco, CA 94143 SPONSORINGi MONITORING AGENCY NAME(S) AND ADORESS(ES)il0 ABSTRACT (Mdaxmum 200wOrWjWork on development and/or validation of analytical methodologies during the first half of the contrac focused on assays for WR 238,605, halofantrine (and its metabolite), WR 6026 (and its metabolites), mefloquine (and its metabolite), artelinic acid, p-aminoheptanophenone (and related compounds), and primaquine (and its metabolite). Work on routine analyses of biological specimens during this period was performed for studies that required determination of concentrations of WR 238,605, halofantrine (and its metabolite), WR 6026 (and its metabolites), mefioquine (and its me: m~lite), paminoheptanophenone (and related compounds), and primaquine (and its metabolite). Where copyrighted material is quoted, permission has been obtained to use such material.Where material from documents designated for limited distribution is quoted, permission has been obtained to use the material.Citations of commercial organizations and trade names in this report do not constitute an official Department of Army endorsement or approval of the products or services of these organizations.In conducting research using animals, the investigator(s) adhered to the *Guide for the Care and Use of Laboratory Animals,O prepared by the Committee on Care and Use of Laboratory Animals of the Institute of Laboratory Resources, National Research Council (NIH Publication No. 86-23, Revised 1985).For the protection of human subjects, the investigator(s) adhered to policies of applicable Federal Law 45 CPR 46.In conducting research utilizing recombinant DNA technology, the investigator(s) adhered to current guidelines promulgated by the National Institutes of Health.In the conduct of research utilizing recombinant DNA, the investigator(s) adhered to the NIH Guidelines for Research Involving Recombinant DNA Molecules.In the conduct of research involving hazardous organisms, the investigator(s) adhered to the CDC-NIH Guide for Biosafety in Microbiological and Biomedical Laboratories. For many years our research group has been actively involved in the development of analytical methods to assay for drug substances in biological fluids for pharmacokinetic, bioavailability, drug metabolism and drug monitoring studies. This report describes the approach we took to develop sensitive (nanograms per milliliter of biological matrix), specific and quantitative analytical methods to support pharmacokinetic and bioavailability studies of candidate chemical warfare antidotes, antiparasitic drugs, radioprotectants and anti-infectious disease drugs.In addition, routine analyses of biological specimens to support pharmacokinetic and bioavailability studies as part of preclinical and clinical investigations undertaken for the purpose of new drug development were performed as a significant adjunct to method development obje...

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Separation of organic amine compounds on silica gel with reversed-phase eluents

Cited by 212 publications

References 22 publications

Effect of temperature on the chromatographic behavior of epirubicin and its analogues on high purity silica using reversed-phase solvents

Effect of temperature on the chromatographic behavior of epirubicin and its analogues on high purity silica using reversed-phase solvents

Determination of pipemidic acid in plasma by normal-phase high-pressure liquid chromatography

Analysis of Investigational Drugs in Biological Fluids - Method Development and Routine Assay

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