82 Citations (SciVal)


Scanning confocal fluorescence microscopy was used to image localized regions of calcein transport across human stratum corneum during constant tow-voltage (iontophoresis) and pulsed high-voltage exposures. Following an electrical protocol, imaging revealed regions of fluorescence which were interpreted as sites where transport of a fluorescent probe (calcein) into the stratum corneum had taken place. Electrically-assisted transport of calcein, whether enhanced by iontophoresis or high-voltage pulsing, appears to occur through intercellular and, to some extent, transcellular pathways into localized regions of stratum comeum that are not associated with appendages. Uniquely associated with the highest voltage pulses used (300 V across the skin) was the appearance of small, brightly fluorescent areas containing nonfluorescent interiors, i.e., fluorescent "rings". We present evidence which suggests that the dark interiors represent sites through which transport occurred during pulsing, but where calcein was no longer present at the time of imaging. Transport of charged microspheres into the stratum corneum was also observed.

Original languageEnglish
Pages (from-to)1363-1370
Number of pages8
JournalJournal of Pharmaceutical Sciences
Issue number12
Publication statusPublished - Dec 1996

Bibliographical note

Funding Information:
We thank V. G. Bose, F. Hueber, L. B. Nonato, and N. G. Turner for technical assistance and Y. A. Chizmadzhev and U. Pliquett for stimulating discussions. This work was supported in part by Army Research Office Grant DAAL03-90-G-0218 (J.C.W.), National Institutes of Health Grants HD27839 (R.H.G., C.C.), GM44884 (R.L.), and GM34077 (J.C.W.) and the Whitaker Foundation (M.R.P.).

ASJC Scopus subject areas

  • Pharmaceutical Science


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