Evaluation of calcium alginate gel as electrode material for alternating current iontophoresis of lidocaine using excised rat skin

Iontophoresis (IOP) is a noninvasive method ofdelivering medication transcutaneously through theskin. The electrodes used in this method shouldtightly fit to rough and irregular surfaces and bebiologically safe, easy to handle and prepare, andcost-effective. To satisfy these requirements,calcium alginate gel can be a candidate electrodefor IOP. Using calcium alginate gel electrodes, weexamined whether lidocaine can be effectivelytransported across an excised rat skin by squarewavealternating current (AC) application. A squarewaveAC with either a 70 % or 80 % duty cyclewas continuously applied to 0.5 % calcium alginategel electrodes containing 10 % lidocaine at 10 Vand 1 kHz for 60 min. Lidocaine concentration wasmeasured using a spectrophotometer and thetemperature of the gel was determined. Thelidocaine concentrations for AC-IOP at the 70 %and 80 % duty cycles were significantly higherthan that without AC-IOP. Furthermore, the groupwith the 80 % duty cycle showed higher lidocaineconcentrations than the group with the 70 % dutycycle. The temperatures of all the groups werelower than 28 ℃ throughout the procedure. Inconclusion, the calcium alginate gel can be used asa possible matrix for IOP electrodes.