Monitoring of urea and potassium by reverse iontophoresis in vitro.
OBJECTIVE
Reverse iontophoresis is an alternative to blood sampling for the monitoring of endogenous molecules. Here, the potential of the technique to measure urea and potassium levels non-invasively, and to track their concentrations during hemodialysis, has been examined.


METHODS
In vitro experiments were performed to test (a) a series of subdermal urea and potassium concentrations typical of the pathophysiologic range, and (b) a decreasing profile of urea and potassium subdermal concentrations to mimic those which are observed during hemodialysis.


RESULTS
(a) After 60-120 min of iontophoresis, linear relationships (p < 0.05) were established between both urea and potassium fluxes and their respective subdermal concentrations. The determination coefficients were above 0.9 after 1 h of current passage using sodium as an internal standard. (b) Reverse iontophoretic fluxes of urea and K(+) closely paralleled the decay of the respective concentrations in the subdermal compartment, as would occur during a hemodialysis session.


CONCLUSIONS
These in vitro experiments demonstrate that urea and potassium can be quantitatively and proportionately extracted by reverse iontophoresis, even when the subdermal concentrations of the analytes are varying with time. These results suggest the non-invasive monitoring of urea and potassium to diagnose renal failure and during hemodialysis is feasible, and that in vivo measurements are warranted.
Wascotte
Valentine
V
Université Catholique de Louvain, Unité de Pharmacie Galénique, Avenue Emmanuel Mounier, Brussels, Belgium.
Delgado-Charro
M Begoña
MB
Rozet
Eric
E
Wallemacq
Pierre
P
Hubert
Philippe
P
Guy
Richard H
RH
Préat
Véronique
V
D000818:Animals; D007478:Iontophoresis / Q000379:methods*; D011188:Potassium / Q000032:analysis*; D012867:Skin / Q000737:chemistry; D013552:Swine; D014508:Urea / Q000032:analysis*
D014508:Urea; D011188:Potassium