EFFECTS OF ALTERNATING-CURRENT IONTOPHORESIS ON DRUG-DELIVERY

Objective: The duration of direct current (DC) iontophoresis is limite d to 10- to 15-minute periods because of electrochemical burns from hy drogen and hydroxide ions generated by the DC current, A new iontophor etic device, the Lectro Patch, uses a low-frequency alternating curren t (AC), AC current is theorized to generate H+ ions during one phase a nd OH- when the current reverses polarity, thus possibly neutralizing pH changes and avoiding burns, This study examined this possibility an d evaluated drug delivery with AC iontophoresis, using hydroxocobalami n. Design: A known amount of hydroxocobalamin dissolved in 6mL of wate r was loaded in Lectro Patches, two of which were then taped on the fo rearms of 10 patient volunteers, One patch was activated to deliver dr ug by AC iontophoresis, The second patch was not activated and served as a control for delivery by diffusion, Trials were run for 2 and 4 ho urs, with both 1,000 mu g/mL and 2,000 mu g/mL concentrations, Setting : Study was conducted with inpatients in an extended care setting usin g volunteers, Main Outcome Measures: Amounts of hydroxocobalamin remai ning in the Lectro Patches after iontophoresis were assayed by spectro photometry, Data were analyzed by ANOVA, Results: No burns occurred, S ignificantly greater losses occurred with 4 hours of iontophoresis tha n with 2 hours (p < 0.05), There was no significant effect of changing the concentration of hydroxocobalamin. Conclusions: AC iontophoresis avoids electrochemical burns; charged drugs can be delivered by AC ion tophoresis; and delivery of drug increases with duration of applicatio n. (C) 1995 by the American Congress of Rehabilitation Medicine and th e American Academy of Physical Medicine and Rehabilitation