Studies in drug transport vs. current in iontophoretic onychomycosis treatment.

An iontophoretic treatment system for onychomycosis, using drug applicators targeting either toe nail only or nail and surrounding tissue, is analyzed. Phase 1 clinical data shows levels of drug delivery that differ unexpectedly from relative dosing level to multiple tissue types. Current monitoring and analysis techniques, coupled with assays of drug delivery into excised nail and cadaver toe, were used to evaluate drug delivery vs. current flow. The results indicate good correlation with piecewise linear models of current flow and extracted drug in the nail-only application. For the nail and surrounding tissue application, assayed drug levels indicate that on average, drug load per unit dose (mA-min) is more efficient into nail than into surrounding tissue (2.38:1 ug/mA-min nail vs. surrounding tissue, n=6, p=0.009).