Related Experiment Video
Updated: Jun 18, 2026

Application of Electrophysiology Measurement to Study the Activity of Electro-Neutral Transporters
Published on: February 3, 2018
Influence of pH on transungual passive and iontophoretic transport
Kelly A Smith1, Jinsong Hao, S Kevin Li
1Division of Pharmaceutical Sciences, College of Pharmacy, University of Cincinnati, 3225 Eden Ave., 136 HPB, Cincinnati, Ohio 45267, USA.
Abstract:
The present study investigated the effects of pH on nail permeability and the transport of ions such as sodium (Na) and chloride (Cl) ions endogenous to nail and hydronium and hydroxide ions present at low and high pH, which might compete with drug transport across hydrated nail plate during iontophoresis. Nail hydration and passive transport of water across the nail at pH 1-13 were assessed. Subsequently, passive and iontophoretic transport experiments were conducted using (22)Na and (36)Cl ions under various pH conditions. Nail hydration was independent of pH under moderate pH conditions and increased significantly under extreme pH conditions (pH >11). Likewise, nail permeability for water was pH independent at pH 1-10 and an order of magnitude higher at pH 13. The results of passive and iontophoretic transport of Na and Cl ions are consistent with the permselective property of nail. Interestingly, extremely acidic conditions (e.g., pH 1) altered nail permselectivity with the effect lasting several days at the higher pH conditions. Hydronium and hydroxide ion competition in iontophoretic transport was generally negligible at pH 3-11 was significant at the extreme pH conditions studied.
More Related Videos
10:45Real-time Iontophoresis with Tetramethylammonium to Quantify Volume Fraction and Tortuosity of Brain Extracellular Space
Published on: July 24, 2017
05:42Measurement of Ion Concentration in the Unstirred Boundary Layer with Open Patch-Clamp Pipette: Implications in Control of Ion Channels by Fluid Flow
Published on: January 7, 2019
Related Concept Videos
Pore Transport and Ion-Pair Transport
Pore transport, also known as convective transport, is a process where small molecules like urea, water, and sugars rapidly cross cell membranes as though there were channels or pores in the membrane. Although direct microscopic evidence is limited but the concept of pores or channels is widely accepted based on physiological evidence. Despite the lack of direct microscopic...
Drug Absorption Mechanism: Passive Membrane Transport
Passive Diffusion: Overview and Kinetics
When administered orally, drugs establish a substantial concentration gradient between the gastrointestinal (GI) lumen and the bloodstream, expediting their diffusion into...
Active Transport
Primary active transporters, like Na+, K+ and -ATPase, directly utilize ATP to move ions across the membrane. These transporters play significant roles in various physiological processes. For instance, Na+, K+ and -ATPase maintain...
Cellular Membranes and Drug Transport
Phospholipids arrange themselves into a bilayer, with hydrophilic heads oriented outward and hydrophobic tails facing inward.
Carrier-Mediated Transport
Active transport involves two types of membrane-spanning transporters: uptake and efflux. Uptake transporters are expressed in the small...