Bulk liquid membrane transport of ferrioxamine B by neutral and ionizable carriers

Journal Article (Journal Article)

Bulk liquid membrane (BLM) transport of ferrioxamine B (FeHDFB ) across an artificial hydrophobia membrane facilitated by neutral and ionizable carriers was studied. Under controlled conditions, ferrioxamine B transport by neutral ionophores follows a simple theoretical model for a diffusion controlled process which predicts a linear dependence of flux upon aqueous-to-chloroform extraction constants. Unsubstituted 18C6 crown ether exhibits the best transport properties among the neutral carriers investigated with a flux of 1.4 × 10 mol s cm . When transport of FeHDFB , metal-free desferrioxamine B, H DFB , and AlHDFB mediated by DC18C6 crown ether was followed, a selectivity was observed with a ratio of measured relative fluxes of 5:3:1, respectively. An ionizable carrier lasalocid {6-[7-[5-ethyl-5-(5-ethyltetrahydro-5-hydroxy-6-methyl-2H-pyran-2-yl)tetrahydro- 3-methyl-2-furanyl]-4-hydroxy-3,5-dimethyl-6-oxonoyl]-2-hydroxy-3-methylbenzoic acid}, negatively charged at neutral pH, outperformed the crown ethers as a ferrioxamine B transporting agent. However, transport by ionizable carriers follows a different mechanism and occurs only when an electrolyte is present in the receiving phase. This requirement was exploited by designing a BLM experiment in which H DFB acts as a counter cation at the receiving interface, whereby FeHDFB and H DFB were transported in opposite directions in a synergistic fashion. When the ionizable salicylic acid moiety of lasalocid is transformed into an ester, lasalocid almost entirely loses its transporting properties. This suggests a co-operative mode of binding in which electrostatic recognition of the FeHDFB cation by lasalocid anion is a prerequisite for a subsequent encapsulation of the amine site in a host-guest fashion. + -10 -1 -2 + + + + + + + 4 4 4

Full Text

Duke Authors

Cited Authors

  • Spasojević, I; Crumbliss, AL

Published Date

  • December 7, 1998

Published In

Start / End Page

  • 4021 - 4027

International Standard Serial Number (ISSN)

  • 0300-9246

Digital Object Identifier (DOI)

  • 10.1039/a804391d

Citation Source

  • Scopus