Chen T, Langer R, Weaver J C
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, USA.
J Investig Dermatol Symp Proc. 1998 Aug;3(2):159-65. doi: 10.1038/jidsymp.1998.32.
High voltage pulsing of human skin (approximately 100 V across the skin, 1 ms pulses) has been hypothesized to cause electroporation of the stratum corneum, and to cause large fluxes of drugs and other molecules across the skin, through newly created aqueous pathways. In contrast, iontophoresis (<0.5 mA per cm2, <1 V across the skin) has long been used in transdermal drug delivery, and is believed to involve pre-existing pathways associated with hair follicles and sweat ducts. Either high voltage pulsing or iontophoresis was applied to human, hairless rat, or black rat snake skin. Hairless rat skin contains more hair follicles than human skin, and snake skin does not contain any hair follicles. All three types of skin had comparable electrical resistances at low voltages; however, the iontophoretic transport of charged fluorescent molecules was significant for human and hairless rat skin, but no transport occured across snake skin, indicating that hair follicles and sweat ducts play a major role in iontophoresis. Electroporation caused large molecular transport for all three types of skin, and involved spontaneously forming localized transport regions, not associated with appendages. These experiments thus provide further support for the hypothesis that high voltage pulsing causes electroporation in the stratum corneum, and that this transport mechanism is fundamentally different from iontophoresis.
据推测，对人体皮肤施加高压脉冲（皮肤两端约100伏，脉冲持续时间1毫秒）会导致角质层发生电穿孔，并使药物和其他分子通过新形成的水性通道大量透过皮肤。相比之下，离子电渗疗法（每平方厘米<0.5毫安，皮肤两端<1伏）长期以来一直用于透皮给药，据信它涉及与毛囊和汗腺导管相关的既有通道。对人体、无毛大鼠或黑鼠蛇的皮肤施加高压脉冲或离子电渗疗法。无毛大鼠皮肤的毛囊比人体皮肤更多，而蛇皮则不含任何毛囊。在低电压下，所有三种类型的皮肤具有相当的电阻；然而，带电荷的荧光分子的离子电渗转运在人体和无毛大鼠皮肤中很显著，但在蛇皮上没有发生转运，这表明毛囊和汗腺导管在离子电渗疗法中起主要作用。电穿孔导致所有三种类型的皮肤都出现大分子转运，并且涉及自发形成的局部转运区域，这些区域与附属器无关。因此，这些实验进一步支持了以下假设：高压脉冲会导致角质层发生电穿孔，并且这种转运机制与离子电渗疗法根本不同。
