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8361970 
Journal Article 
Enhanced percutaneous absorption via iontophoresis I. Evaluation of an in vitro system and transport of model compounds 
Bellantone, NH; Rim, S; Francoeur, ML; Rasadi, B 
1986 
Yes 
International Journal of Pharmaceutics
ISSN: 0378-5173
EISSN: 1873-3476 
30 
1 
63-72 
English 
In vitro methodology was developed to investigate the iontophoretic transport of select ionic and non-ionic compounds across hairless mouse skin. Using sodium benzoate and a constant current of 0.1 mA, it was observed that alterations in the diffusion cell configuration and/or return electrode placement relative to the membrane had little effect on the transport of benzoate ions, thus permitting the use of a simple experimental design. Increases in applied current (from 0.0 to 0.2 mA) produced a linear increase in observed benzoate flux. The steady-state flux was also slightly increased (apparently linearly) with greater donor concentrations, but was reduced when competitive ions (NaCl) were added to the donor chamber. Employing a direct current of 0.1 mA and identical solutions, the iontophoretic flux enhancement ratios (flux with current/flux without current) were calculated for benzoate (22.61) and the phenethylamine cation (43.32, using reversed electrode polarity). The flux of a non-ionic compound (benzyl alcohol) was not significantly altered during the application of a 0.1 mA direct current. Upon termination of the current in benzoate iontophoresis experiments (0.1 mA × 3 h), subsequent fluxes were observed to be quite inconsistent. Many yielded values fairly close to the average control (no current exposure) flux for the benzoate ion. However, several of the residual fluxes were nearly 10-fold higher than the control, suggesting compromised skin barrier integrity of a variable nature. This occasional alteration in membrane transport resistance was not, however, observed in experiments performed with benzyl alcohol. It is speculated that the diffusional path followed specifically by ionized species undergoes sporadic current-related changes, and that the flux of the uncharged benzyl alcohol is not affected by alterations in this path. These results suggest that iontophoresis may be a convenient means by which to achieve constant and readily controllable transdermal delivery, locally or to the systemic circulation, for ionized drug species (including peptides). Transport rates may be optimized by adjustment of donor ionic composition and utilization of current densities and patterns deemed physiologically appropriate. © 1986. 
iontophoresis-in vitro methodology-model compounds-hairless mouse-transdermal drug delivery