title: Salt effects on the interaction of an amphiphilic model molecule with immobilized phosphatidylcholine monolayers.
abstract: The retention of hydrocortisone (used as an amphiphilic model solute) on an immobilized artificial membrane (IAM) column was investigated in relation to the mobile phase concentration of three sodium salts (representing different rankings in the Hofmeister series, i.e. perchlorate, chloride and sulfate) in order to provide insight into the nature of the solute interactions with phospholipid monolayers. The influence of the salt series on solute retention was found to follow the Hofmeister series, emphasizing the role of hydrophobic effect in the solute retention mechanism on phospholipid monolayers. Retention models based on the extended Wyman relations (preferential interaction theory) were developed to analyze more quantitatively the salt effects on the hydrocortisone retention factor. This analysis as well as additional thermodynamic study suggested that the hydrocortisone binding to IAM involved both an insertion into the hydrophobic inside governed by hydrophobic effects and contacts with the interfacial region implying interactions such as van der Waals interactions/hydrogen bonds between the solute hydroxyl groups and the polar headgroups of phospholipidmonolayers.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Haroun
authors.forename: Christelle
authors.initials: C
authors.lastname: Dufresne
authors.forename: Eric
authors.initials: E
authors.lastname: Jourdan
authors.forename: Anne
authors.initials: A
authors.lastname: Ravel
authors.forename: Catherine
authors.initials: C
authors.lastname: Grosset
authors.forename: Annick
authors.initials: A
authors.lastname: Villet
authors.forename: Eric
authors.initials: E
authors.lastname: Peyrin
mesh_terms: D002851:Chromatography, High Pressure Liquid; D006854:Hydrocortisone / Q000737:chemistry*; D008567:Membranes, Artificial; D010713:Phosphatidylcholines / Q000737:chemistry*; D012044:Regression Analysis; D013816:Thermodynamics
chemical_list: D008567:Membranes, Artificial; D010713:Phosphatidylcholines; D006854:Hydrocortisone