Study of Transdermal Delivery of Lidocaine by AC Iontophoresis : Interrelationship of frequency, voltage and the concentration of lidocaine in tissue.

离子导入是一种电方法，已被用于加强药物在皮肤上的运输。这种输送方法利用电力将电离物质通过皮肤或粘膜输送。利用直流电离子电泳作为一种基于该原理的给药方法已被广泛应用。然而，诸如皮肤灼烧、瘙痒和发红等并发症与直流离子导入有关。此外，极化效应限制了直流离子电泳的工作时间。交流电比直流电产生更少的电极极化，避免了上述副作用。研究发现，交流电场能更有效地在皮肤上传输药物。提出了高频交流离子透入机理的理论模型。我们发现利多卡因在体内和体外均可通过大鼠腹部皮肤和玻璃膜进行转运。在体外，我们采用两个圆柱形玻璃扩散细胞平行于玻璃膜和大鼠腹部皮肤，在体内，我们研制了两个铂圆形板紧密贴合大鼠皮肤的原始给药细胞。施加频率和电压后的洛多卡因浓度明显高于被动扩散。在这些研究中使用了正弦波，但现在我们正试图寻找最佳的电条件，例如使用方波。为了更有效地运输药物，我们试图开发新的细胞，并将该系统应用于另一种药物，非电离分子和大分子等。

Iontophoresis is one of electrical methods that have been employed to enhance drug transportation across the skin. This delivery method transports ionized substances through skin or mucous membranes utilizing an electrical force. Iontophoresis using direct current (DC) has been used as a drug delivery method based on the principle. However complications such as skin burning, itching and redness have been associated with DC iontophoresis. Furthermore, the operating time of DC iontophoresis is limited because of the polarization effect.Alternating current produces less electrode polarization than DC and avoids side effects mentioned above. It was found that AC electric field transport drug more effectively across the skin. We proposed a theoretical model of the mechanism of high frequency AC iontophoresis.We found that lidocaine could be transported through extirpated abdominal rat skin and cellophane membrane in vivo and in vitro. In vitro we used two cylindrical glass diffusion cells in parallel to the cellophane membrane and extirpated abdominal rat skin, In vivo we developed original drug delivery cell with two platinum circular plates to fit rat skin tightly.The lodocaine concentration after the application of frequency and voltage increased than passive diffusion significantly.A sinusoidal wave was used in these studies, but now we are trying to search for the best electrical condition, for example using a square wave.To transport drugs more effectively we try to develop new cells and apply this system for another drug, non-ionized molecule and macromolecule and so on.