Rate and extent of ion-exchange process: the effect of physico-chemical characteristics of salicylate anions

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

“…Consistently, reduced loading of di-COOH was observed previously with Smopex DS-218v fiber when compared with monovalent salicylates. 15 Bhandari et al 21 observed also that the capacity of weak base resins to bind a dibasic acid was half of that for monobasic acids demonstrating occupation of two sites on the resin.…”

“…The quantities of anionic compounds were analyzed by HPLC as previously described. 15 The loading procedures were performed at least in triplicate.…”

“…The amount of compound released from the fiber at each time-point was analyzed by HPLC. 15 The loading and release experiments were performed on a shaker (180 movements/min) in sealed amber glass bottles at ambient temperature. The release experiments were performed in triplicate.…”

“…The electrostatic interaction between the bound divalent compound and the ionexchanger is stronger as compared with the monovalent compound (SA) due to the dual site binding. 15,[21][22][23][24][25] The formed strong interaction hinders the release of di-COOH from the fibers, especially in the case of monovalent extracting electrolyte, by preferring the divalent di-COOH over the chloride-ion (electroselectivity) (Tab. 3, Figs.…”

“…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.…”