High Performance Liquid Chromatography on Calixarene-Bonded Silica Gels. III. Separations of cis/trans Isomers of Proline-Containing Peptides

Gebauer, Sebastian; Friebe, Sieglinde; Scherer, Gerd; Gübitz, Gerald; Krauss, Gerhard

doi:10.1093/chromsci/36.8.388

Cited by 53 publications

(29 citation statements)

References 13 publications

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“…His group estimated isomerization rate constants and the activation barrier of some proline-containing dipeptides by computer-supported Damköhler analysis, a method that is commonly used in chemical engineering. Krauss et al [12][13][14][15] and Gesquiere et al [16] also found isomerization of prolinecontaining peptides taking place on different stationary phases in HPLC and Thomas et al [17], Wüthrich et al [18], and Moroder et al [19] in NMR studies.…”

Section: Enalaprilat (1-[n-[(s)-1-carboxy-3-phenylpropyl]-l-alanyl]-mentioning

confidence: 94%

Determination of the cis‐trans isomerization barrier of enalaprilat by dynamic capillary electrophoresis and computer simulation

Trapp

Schurig

2004

Electrophoresis

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Dynamic capillary electrophoresis (DCE) and computer simulation of the elution profiles with the stochastic model has been applied to determine the isomerization barriers of the angiotensin converting enzyme inhibitor enalaprilat. The separation of the rotational cis-trans isomeric drug has been performed in an aqueous 20 mM borate buffer at pH 9.3. Interconversion profiles featuring plateau formation and peak broadening were observed. To evaluate the rate constants k(cis-->trans) and k(trans-->cis) of the cis-trans isomerization from the experimental electropherograms obtained by dynamic capillary electrophoresis, elution profiles were analyzed by a simulation with iterative convergence to the experimental data using the ChromWin software which requires the total migration times of the individual isomers t(R), the electroosmotic break-through time t(0), the plateau height h(plateau), the peak widths at half height of the individual isomers w(h), as well as the peak ratio of the isomers as experimental data input. From temperature-dependent measurements between 0 degrees and 15 degrees C the thermodynamic parameters Delta G, Delta H and Delta S, the rate constants k(cis-->trans) and k(trans-->cis) and the kinetic activation parameters Delta G*, Delta H*, and Delta S* of the cis-trans isomerization of enalaprilat were obtained. From the activation parameters the isomerization barriers at 37 degrees C were calculated to be Delta G* (trans-->cis) = 87.2 kJ.mol(-1) and Delta G*(cis-->trans) = 91.9 kJ.mol(-1).

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Section: Enalaprilat (1-[n-[(s)-1-carboxy-3-phenylpropyl]-l-alanyl]-mentioning

confidence: 94%

Determination of the cis‐trans isomerization barrier of enalaprilat by dynamic capillary electrophoresis and computer simulation

Trapp

Schurig

2004

Electrophoresis

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“…Since the publication of Effect of molecular structure and conformational change of proline-containing dipeptides in reversed phase chromatography in 1982, 69 many articles dealing with interconversion profiles obtained by DHPLC of peptidyl-prolin dipeptides have been published, [70][71][72][73][74][75][76][77] but not in all cases the rate constants of cis-trans isomerization were determined. In 1984, Horváth's group 70 published a theoretical article about the determination of rate constants in dynamic reversed-phase chromatography with the help of the Damköhler number.…”

Section: Liquid Chromatographymentioning

confidence: 99%

Determination of enantiomerization barriers by dynamic and stopped‐flow chromatographic methods

2001

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In recent years, dynamic chromatography and stopped-flow chromatographic techniques have become versatile tools for the determination of enantiomerization and isomerization barriers. Increasing demands for the stereochemical safety of chiral drugs contributed to the rapid development of new techniques. New computer-aided evaluation systems allow the on-line determination of interconversion barriers from the experimental chromatograms. Both dynamic chromatography and stopped-flow chromatography have been applied to the entire range of chromatographic methods (GC, SFC, HPLC, CE).

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“…Calixarene-based stationary phases have also proven to be superior in their separation of structurally similar compounds such as o, m, p-substituted aromatics [6 -9], polyaromatic hydrocarbons [4,9,10], cis/trans-isomers of dipeptides [11], and thioxanthenes [5] compared to conventional C 18 phases [4,6,8,11]. However, up to now the retention mechanisms of the calixarene-based stationary phases are not well understood.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the retention behaviour of steroids with calixarene‐based stationary phases by modern NMR spectroscopy

Skogsberg

Händel

Gesele

et al. 2003

J of Separation Science

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Investigation of the retention behaviour of steroids with calixarene-based stationary phases by modern NMR spectroscopy A separation of four structurally similar steroids was performed on two calix[8]arene based stationary phases. It was observed that two of the steroids had a reversed retention order when the columns were changed. This implies that two different retention mechanisms are taking place when the analytes are separated. In order to evaluate the mechanism responsible for the reversal of the retention order an extensive study of the interactions between the stationary phases and the analytes was undertaken. By performing a series of transferred NOESY measurements in the suspended state valuable information was obtained about the strengths of the interactions between the analytes and the stationary phases. The magnitudes of the integrals from the trNOESY measurements showed a good correlation with the k9 values obtained from the chromatographic evaluation. The retention mechanism is based mainly on hydrophobic interactions. However, the reversal of the elution order was mainly due to an additional p-p interaction between one of the analytes and the stationary phase.

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High Performance Liquid Chromatography on Calixarene-Bonded Silica Gels. III. Separations of cis/trans Isomers of Proline-Containing Peptides

Cited by 53 publications

References 13 publications

Determination of the cis‐trans isomerization barrier of enalaprilat by dynamic capillary electrophoresis and computer simulation

Determination of the cis‐trans isomerization barrier of enalaprilat by dynamic capillary electrophoresis and computer simulation

Determination of enantiomerization barriers by dynamic and stopped‐flow chromatographic methods

Investigation of the retention behaviour of steroids with calixarene‐based stationary phases by modern NMR spectroscopy

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