In vivo efficacy and safety of skin electroporation

This article reviews the studies on skin electroporation carried out in vivo in animals and emphasizes its potential therapeutic applications for transdermal and topical drug delivery. In agreement with in vitro studies, transport across skin due to high-voltage pulses in vivo was shown to increase by orders of magnitude on a timescale of minutes. Increased transdermal transport was measured by systemic blood uptake and/or pharmacological response, and demonstrated for calcein, a fluorescent tracer, fentanyl, a potent analgesic and flurbiprofen, an antiinflammatory drug. Combined electroporation with iontophoresis was shown to provide rapidly responsive transdermal transport of luteinizing hormone releasing hormone ex vivo as well. These data underline the potential of skin electroporation for improving the delivery profile of existing conventional transdermal patches, but also for replacing the injectable route.High-voltage pulses can increase drug permeation within and across skin but are also an efficient tool to permeabilize the membrane of cells of the cutaneous or subcutaneous tissue. This was shown beneficial for targeting cutaneous cells with oligonucleotides or genes and might open new opportunities for gene therapy and DNA vaccination.The safety of the application of high-voltage pulses on skin was assessed in vivo, using histological and visual scores, and bioengineering methods. While changes in skin barrier and function were observed, the irritation was mild and short-lived. Further optimization of the electrode configuration for improved targeting of the stratum corneum should still improve tolerance and levels of sensation.