Effect of ion-exchange fiber structure on the binding and release of model salicylates

The Effect of Valence on the Ion-Exchange Process: Theoretical and Experimental Aspects on Compound Binding/Release

“…1A and 2) and previous observations with other ion-exchange fibers. 13,15,16,26 Accordingly, the exchange of chloride was increased when its concentration in the extracting solution was increased. Thus, the electrolyte concentration can be utilized, in addition to the valence of the electrolyte, to control (improve, attenuate) the release of compounds from the ion-exchangers.…”

“…Compound release by pure ion-exchange reaction should produce constant K values across the equilibration stages (1)(2)(3) Previously, we have studied K values of the ionexchange process with monovalent compounds, like SA. 16 In the present study, ion-exchange equilibrium constants of the divalent compound (di-COOH) were also calculated. Eq.…”

“…Consistently, recent studies have shown that physico-chemical characteristics of drugs (especially hydrophobicity) and characteristics of fiber framework and ion-exchange groups affect drug incorporation and release properties from the non-cross-linked fibers. 8,[12][13][14][15][16] Formation of non-electrostatic interactions may hinder the release of bound compounds from the fiber. 8,12,13,15,16 However, if a fraction of the compounds is incorporated to the fiber by non-specific interactions only (without ionic bonding), the extent of release may be even higher than possibly could be obtained by ionexchange only.…”

“…8,[12][13][14][15][16] Formation of non-electrostatic interactions may hinder the release of bound compounds from the fiber. 8,12,13,15,16 However, if a fraction of the compounds is incorporated to the fiber by non-specific interactions only (without ionic bonding), the extent of release may be even higher than possibly could be obtained by ionexchange only. 15 The more non-specific interactions are formed, the more difficult is an accurate regulation of drug release profiles from the fiber by ion-exchange approach.…”

Characterisation of the Ion Exchange Reaction Between Propranolol-H+ or K+ with Amberlite™ IRP 69 Resin by Both, Isothermal Titration Calorimetry and (Flame) Photometric Equilibrium Analysis

“…It is a common rule that ion-ion-interactions are stronger than non-specific forces, and this fact results in non-constant and decreasing molar reaction enthalpies with increased propranolol content, as was measured in the present study. It has been hypothesised for substituted salicylic acid derivatives of different lipohilicity [25,26] that non-specific interactions between ion exchanger polymers and drug-like molecules may exist. However, in the present study, for the first time evidence for such type of interaction has been experimentally found.…”