Iontophoretic permselectivity of mammalian skin: characterization of hairless mouse and porcine membrane models.
OBJECTIVE
To evaluate the transport number of Na+, and the isoelectric point, of two skin membranes frequently used for iontophoretic in vitro research.


METHODS
Na+ transport numbers were determined by the Hittorf method or by the measurement of membrane potential. The skin isoelectric point was deduced from the electroosmosis of mannitol (a polar non-electrolyte) as a function of pH.


RESULTS
The Na+ transport number across porcine skin, like that for hairless mouse, indicated a modest cation permselectivity. Consistent with this observation, the isoelectric points of porcine and hairless mouse skin were determined to be in the ranges of 3.5-3.75 and 4.5-4.6, respectively. That is, at physiological pH, both of these model membranes supports a net negative charge.


CONCLUSIONS
The permselective properties of porcine and hairless mouse skin are similar (but with the porcine membrane having apparently fewer basic or more weakly-acidic groups than that of the mouse) and consistent with the characteristics, which have been deduced elsewhere, of human skin.
Luzardo-Alvarez
A
A
Departamento de Farmacia e Tecnoloxía Farmacéutica, Facultade de Farmacia, Universidade de Santiago de Compostela, Spain.
Rodríguez-Fernández
M
M
Blanco-Méndez
J
J
Guy
R H
RH
Delgado-Charro
M B
MB
D000818:Animals; D001692:Biological Transport; D002412:Cations; D005260:Female; D005712:Galvanic Skin Response / Q000502:physiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007478:Iontophoresis / Q000379:methods*; D007526:Isoelectric Point; D008566:Membranes / Q000378:metabolism; D051379:Mice; D008812:Mice, Hairless; D012867:Skin / Q000378:metabolism*; D012869:Skin Absorption; D012964:Sodium / Q000493:pharmacokinetics; D013552:Swine
D002412:Cations; D012964:Sodium