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Mechanistic Modeling of Reversed-Phase Chromatography of Insulins with Potassium Chloride and Ethanol as Mobile-Phase Modulators

Arkell, Karolina LU ; Breil, Martin P.; Søndergaard Frederiksen, Søren and Nilsson, Bernt LU (2017) In ACS Omega 2. p.136-146
Abstract
The purpose of this study was to investigate the adsorption mechanism in reversed-phase chromatography (RPC) of proteins and to develop a model for the effect of dual mobile phase modulators—a salt and an organic solvent—on this process. Two different adsorption mechanisms were considered: (1) pure association of a protein molecule and one or more ligands and (2) displacement of the organic modulator, with which the adsorbent is saturated, by the protein upon association with one or more ligands. One model was then derived from each of the two considered mechanisms, combining thermodynamic theories on salting-in, RPC, and the solubility of proteins. The model was then applied to chromatographic data from an earlier report as well as... (More)
The purpose of this study was to investigate the adsorption mechanism in reversed-phase chromatography (RPC) of proteins and to develop a model for the effect of dual mobile phase modulators—a salt and an organic solvent—on this process. Two different adsorption mechanisms were considered: (1) pure association of a protein molecule and one or more ligands and (2) displacement of the organic modulator, with which the adsorbent is saturated, by the protein upon association with one or more ligands. One model was then derived from each of the two considered mechanisms, combining thermodynamic theories on salting-in, RPC, and the solubility of proteins. The model was then applied to chromatographic data from an earlier report as well as supplementary data for solubility and vapor–liquid equilibria, and case-specific simplifications were made. We found that an adaptation of Kirkwood’s electrostatic theories to hydrophobic interaction chromatography describes the observed effect of KCl well. Combining chromatographic and solubility data for one of the insulins, we concluded that the variation in the activity coefficient of the insulin with respect to the concentration of ethanol alone cannot describe its effect on retention. Consequently, one or more other phenomena must affect the adsorption process. Our second model fits the retention data well, supporting the hypothesis that ethanol is directly involved in the adsorption mechanism in this case. Using additional experiments at a high-protein load, we extended the linear-range equilibrium model into a dynamic model for preparative conditions. This model shows good agreement with the high-load data for one of the insulin variants, without any additional effects of the modulator concentrations on the adsorption capacity. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
ACS Omega
volume
2
pages
136 - 146
publisher
American Chemical Society (ACS)
external identifiers
  • wos:000395862400018
  • scopus:85028919836
ISSN
2470-1343
DOI
10.1021/acsomega.6b00248
language
English
LU publication?
yes
id
103e82f2-2a97-42c3-9085-27acd1ad0701
date added to LUP
2017-02-05 11:39:28
date last changed
2017-10-01 05:29:54
@article{103e82f2-2a97-42c3-9085-27acd1ad0701,
  abstract     = {The purpose of this study was to investigate the adsorption mechanism in reversed-phase chromatography (RPC) of proteins and to develop a model for the effect of dual mobile phase modulators—a salt and an organic solvent—on this process. Two different adsorption mechanisms were considered: (1) pure association of a protein molecule and one or more ligands and (2) displacement of the organic modulator, with which the adsorbent is saturated, by the protein upon association with one or more ligands. One model was then derived from each of the two considered mechanisms, combining thermodynamic theories on salting-in, RPC, and the solubility of proteins. The model was then applied to chromatographic data from an earlier report as well as supplementary data for solubility and vapor–liquid equilibria, and case-specific simplifications were made. We found that an adaptation of Kirkwood’s electrostatic theories to hydrophobic interaction chromatography describes the observed effect of KCl well. Combining chromatographic and solubility data for one of the insulins, we concluded that the variation in the activity coefficient of the insulin with respect to the concentration of ethanol alone cannot describe its effect on retention. Consequently, one or more other phenomena must affect the adsorption process. Our second model fits the retention data well, supporting the hypothesis that ethanol is directly involved in the adsorption mechanism in this case. Using additional experiments at a high-protein load, we extended the linear-range equilibrium model into a dynamic model for preparative conditions. This model shows good agreement with the high-load data for one of the insulin variants, without any additional effects of the modulator concentrations on the adsorption capacity.},
  author       = {Arkell, Karolina and Breil, Martin P. and Søndergaard Frederiksen, Søren and Nilsson, Bernt},
  issn         = {2470-1343},
  language     = {eng},
  month        = {01},
  pages        = {136--146},
  publisher    = {American Chemical Society (ACS)},
  series       = {ACS Omega},
  title        = {Mechanistic Modeling of Reversed-Phase Chromatography of Insulins with Potassium Chloride and Ethanol as Mobile-Phase Modulators},
  url          = {http://dx.doi.org/10.1021/acsomega.6b00248},
  volume       = {2},
  year         = {2017},
}