Transdermal delivery of lidocaine in vitro by alternating current

The purpose of this study was to investigate whether lidocaine could be transported through excised rat skin in vitro using alternating current (AC). In addition, the relationships between factors such as voltage and frequency, and transported lidocaine concentration were studied using the in vitro model. A pair of platinum plate electrodes was installed at opposite ends of two cylindrical glass cells in parallel to the full-thickness rat skin. The donor compartment was filled with 10 % lidocaine hydrochloride, and the receptor compartment with Ringer solution. A sinusoidal wave was applied between the electrodes at 5 kinds of constant voltages at 1 kHz and at 4 kinds of frequencies at 20 volts. Our experimental system was successfully used to quantify the concentration of transported lidocaine induced by AC application. The applied sinusoidal waves evoked the transport of lidocaine through the rat skin at every voltage and frequency protocol. Our results suggest that the applied electric voltage and frequency affect the movement of the lidocaine ions. We conclude that the transdermal delivery of lidocaine by AC iontophoresis has a possibility to use for local anesthesia and the pain management of the skin.