title: Ion-exchange fibers and drugs: a transient study.
abstract: The objective of this study was to theoretically model and experimentally measure the kinetics and extent of drug release from different ion-exchange materials using an in-house-designed flow-cell. Ion-exchange fibers (staple fibers and fiber cloth) were compared with commercially available ion-exchange materials (resins and gels). The functional ion-exchange groups in all the materials were weak -COOH or strong -SO3H groups. The rate and extent of drug release from the fibers (staple fiber>fiber cloth) was much higher than that from the resin or the gel. An increase in the hydrophilicity of the model drugs resulted in markedly higher rates of drug release from the fibers (nadolol>metoprolol>propranolol>tacrine). Theoretical modelling of the kinetics of ion exchange provided satisfactory explanations for the experimental observations: firstly, a change in the equilibrium constant of the ion-exchange reaction depending on the drug and the ion-exchange material and, secondly, a decrease in the Peclet number (Pe) with decreasing flow-rate of the drug-releasing salt solution.
authors.affiliation: Laboratory of Physical Chemistry and Electrochemistry, Helsinki University of Technology, P.O. Box 6100, FIN-02015 HUT, Finland. marja.vuorio@hut.fi
authors.forename: M
authors.initials: M
authors.lastname: Vuorio
authors.forename: J A
authors.initials: JA
authors.lastname: Manzanares
authors.forename: L
authors.initials: L
authors.lastname: Murtomäki
authors.forename: J
authors.initials: J
authors.lastname: Hirvonen
authors.forename: T
authors.initials: T
authors.lastname: Kankkunen
authors.forename: K
authors.initials: K
authors.lastname: Kontturi
mesh_terms: D007474:Ion Exchange; D007475:Ion Exchange Resins / Q000737:chemistry* / Q000493:pharmacokinetics; D008962:Models, Theoretical; D004364:Pharmaceutical Preparations / Q000737:chemistry* / Q000378:metabolism; D013784:Textiles
chemical_list: D007475:Ion Exchange Resins; D004364:Pharmaceutical Preparations