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Updated: Jun 28, 2026

Models and Methods to Evaluate Transport of Drug Delivery Systems Across Cellular Barriers
Published on: October 17, 2013
Validation of carrier-mediated transport of H(+) and Na(+) through mobile-site membranes
1Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, U.S.A.
Abstract:
The response of membranes containing neutral ion carriers of either H(+) or Na(+) to an externally-applied potential step was investigated using previously developed techniques for the analysis of charge and mass transport in ion-selective membranes. The results from constant-resistance membranes, e.g. membranes with unperturbed negative site concentration profiles, showed that tridodecylamine behaved as a carrier for H(+), and there was no evidence for proton hopping from stationary carriers. In addition, the experimental outcome supported the assumption of a failure of the Donnan exclusion principle at very low pH levels in these membranes. The results from membranes containing the Na(+) carrier illustrated the significant concentration polarization of ionic species, which was related to significant changes in bulk membrane resistance.
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