title: Extraction of amino acids by reverse iontophoresis: simulation of therapeutic monitoring in vitro.
abstract: Reverse iontophoresis across the skin has been investigated as alternative, non-invasive method for clinical and therapeutic drug monitoring. This research investigated the reverse iontophoretic extraction of 19 amino acids present at clinically relevant levels in the subdermal compartment of an in vitro diffusion cell. Over a simulated, systemic concentration range of 0-500 microM, the extraction of amino acids was linear. Charged amino acids were extracted towards the electrode of opposite polarity, while zwitterionic species were extracted to both anode and cathode with the latter predominating. The reverse iontophoretic extraction flux was a linear function of amino acid isoelectric point, reflecting the different contributions of electromigration and electroosmosis to electrotransport. Overall, the results confirm the feasibility of monitoring amino acids at clinically relevant levels and provide an incentive for in vivo research to further explore the clinical potential of reverse iontophoresis for the non-invasive monitoring of amino acids.
authors.affiliation: Baxter R & D Europe, Department of Renal Solutions, Nivelles, Belgium. anke_siega@gmx.de
authors.forename: Anke
authors.initials: A
authors.lastname: Sieg
authors.forename: Fabienne
authors.initials: F
authors.lastname: Jeanneret
authors.forename: Marc
authors.initials: M
authors.lastname: Fathi
authors.forename: Denis
authors.initials: D
authors.lastname: Hochstrasser
authors.forename: Serge
authors.initials: S
authors.lastname: Rudaz
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Veuthey
authors.forename: Richard H
authors.initials: RH
authors.lastname: Guy
authors.forename: M Begoña
authors.initials: MB
authors.lastname: Delgado-Charro
mesh_terms: D000596:Amino Acids / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D000818:Animals; D002853:Chromatography, Liquid; D015194:Diffusion Chambers, Culture; D016903:Drug Monitoring / Q000379:methods*; D053841:Electroosmosis; D005240:Feasibility Studies; D007478:Iontophoresis; D007526:Isoelectric Point; D013058:Mass Spectrometry; D015394:Molecular Structure; D010539:Permeability; D015203:Reproducibility of Results; D012867:Skin / Q000737:chemistry* / Q000378:metabolism; D013329:Structure-Activity Relationship; D013552:Swine; D013997:Time Factors
chemical_list: D000596:Amino Acids