Transport of small anionic and neutral solutes through chitosan membranes: Dependence on crosslinking and chelation of divalent cations

Abstract

[Excerpt] Chitosan membranes were prepared by solvent casting and crosslinked with glutaraldehyde at several ratios under homogenous conditions. The crosslinking degree varying from 0 to 20% is defined as the ratio between the total aldehyde groups and the amine groups of chitosan. Permeability experiments were conducted using a side-by-side diffusion cell to determine the flux of small molecules of similar size, but holding different chemical moieties, either ionised (benzoic acid, salicylic acid and phthalic acid) or neutral (2-phenylethanol) at physiological pH. The permeability of the different model molecules revealed to be dependent on the affinity of those structurally similar molecules to chitosan, i.e., related to the partition coefficient determined in an independent experiment. [...]