Pharmaceutical Research

, Volume 7, Issue 2, pp 134–143

DC Electrical Properties of Frozen, Excised Human Skin

  • Gerald B. Kasting
  • Lisa A. Bowman
Article

Abstract

DC current-voltage relationships and sodium ion transport measurements for human allograft skin immersed in saline buffers have been determined using a four terminal potentiometric method and diffusion cells of our own design. About three-fourths of the skin samples were deemed suitable for study on the basis of their high resistivities and similar j–V characteristics. Most of these samples yielded sodium ion permeability coefficients less than or equal to those reported for human skin in vivo. The current–voltage relationship in these tissues was time dependent, highly nonlinear, and slightly asymmetric with respect to the sign of the applied potential. Skin resistance decreased as current or voltage increased. For current densities less than 15 µA/cm2 and exposure times of 10–20 min, this decrease was almost completely reversible; at higher current densities, both reversible and irreversible effects were observed. The overall dependence of current on voltage was nearly exponential and was satisfactorily described by an equation of the form j ∼ sinh V. Diffusion potentials, sodium ion membrane transference numbers, and sodium ion flux enhancement factors during iontophoresis were measured for skin immersed both in normal saline solutions and in saline solutions of differing concentrations. The sign of the diffusion potentials and the value of the sodium ion transference number (0.51 in normal saline at pH 7.4) indicated a weak permselectivity of the skin for transport of sodium ion versus chloride. At a current density of 71 µA/cm2 and transmembrane potentials in the range of 1.1–1.6 V, the flux enhancement for sodium ion was three to five times greater than that predicted for an uncharged homogeneous membrane according to electrodiffusion theory. For transmembrane potentials less than 0.17 V, agreement of this theory with the data was better but still incomplete.

iontophoresis human skin current–voltage characteristic sodium ion transport 

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REFERENCES

  1. 1.
    A. K. Banga and Y. W. Chien. J. Control. Release 7:1–24 (1988).Google Scholar
  2. 2.
    R. R. Burnette and D. Marrero. J. Pharm. Sci. 75:738–743 (1986).Google Scholar
  3. 3.
    B. R. Meyer, W. Kreis, J. Eshbach, V. O'Mara, S. Rosen, and D. Sibalis. Clin. Pharmacol. Ther. 44:607–612 (1988).Google Scholar
  4. 4.
    G. B. Kasting and J. C. Keister. J. Control. Release 8:195–210 (1989).Google Scholar
  5. 5.
    R. J. Scheuplein. In A. Jarrett (ed.), The Physiology and Pathophysiology of the Skin, Vol. 5, Academic Press, London, 1978, pp. 1659–1752.Google Scholar
  6. 6.
    R. T. Plessinger. Personal communication, Ohio Valley Skin and Tissue Center.Google Scholar
  7. 7.
    J. Ostrenga, C. Steinmetz, and B. Poulson. J. Pharm. Sci. 60:1175–1179 (1971).Google Scholar
  8. 8.
    R. C. Weast (ed.). Handbook of Chemistry and Physics, 62nd ed., CRC Press, Boca Raton, FL, 1981, p. D-232.Google Scholar
  9. 9.
    G. B. Kasting, E. W. Merritt, and J. C. Keister. J. Membrane Sci. 35:137–159 (1988).Google Scholar
  10. 10.
    A. Finklestein and A. Mauro. In Handbook of Physiology, Section 1: The Nervous System, Vol. I, Am. Physiol. Soc., Bethesda, MD, 1977, Chap. 6, pp. 161–213.Google Scholar
  11. 11.
    R. T. Tregear. Nature 205:600–601 (1965).Google Scholar
  12. 12.
    R. T. Tregear. J. Invest. Dermatol. 46:16–23 (1966).Google Scholar
  13. 13.
    G. B. Kasting and L. A. Bowman. In preparation.Google Scholar
  14. 14.
    A. J. Bard and L. R. Faulkner. Electrochemical Methods: Fundamentals and Applications, Wiley, New York, 1980, pp. 87–118.Google Scholar
  15. 15.
    J. C. Keister and G. B. Kasting. The mechanism of iontophoresis, Proceedings of NIH conference on physical and chemical enhancement of drug transport through skin, Bethesda, MD, May 23–24, 1988.Google Scholar
  16. 16.
    P. R. Bevington. Data Analysis for the Physical Sciences, McGraw-Hill, New York, 1969, p. 235 (Marquardt algorithm).Google Scholar
  17. 17.
    R. R. Burnette and B. Ongpipattanakul. J. Pharm. Sci. 76:765–773 (1987).Google Scholar
  18. 18.
    R. C. Weast (ed.). Handbook of Chemistry and Physics, 65th ed., CRC Press, Boca Raton, FL, 1984, pp. D171–D173.Google Scholar
  19. 19.
    J. C. Keister and G. B. Kasting. Unpublished results.Google Scholar
  20. 20.
    T. J. Franz. J. Invest. Dermatol. 64:190–195 (1975).Google Scholar

Copyright information

© Plenum Publishing Corporation 1990

Authors and Affiliations

  • Gerald B. Kasting
    • 1
  • Lisa A. Bowman
    • 1
  1. 1.The Procter & Gamble CompanyMiami Valley LaboratoriesCincinnati

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