Factors affecting sulfisoxazole transport through excised rat skin during iontophoresis.

Permeation of sulfisoxazole (SIX) across the excised rat skin were studied using two chamber cell with four electrodes, under three successive experimental conditions: without current for 3 h (treatment I), with current for 4 h (treatment II) and without current for 3 h (treatment III). Transport of SIX was significantly increased by iontophoresis. The enhancement ratio of SIX flux were reasonably predicted by Goldman's equation. There was no significant difference (p less than 0.05) between the flux in treatment I and treatment III. On the basis of the flux reversibility, it was concluded that skin alteration did not occur when the applied electric potential was below 5.025 V. Although a prominent current-induced volume flow (from the anodal side to the cathodal side) was observed during current exposure, SIX flux was not influenced by the volume flow. The flux enhancement of SIX was mainly dependent on transdermal potential difference.