Transdermal delivery of Clostridium botulinum toxin type A by pulsed current iontophoresis

LETTER TO THE EDITOR. Summary. In this study we demonstrate that iontophoresis allowed the delivery of BoNT type A (BoNT/A) through living rat skin. We used a Food and Drug Administration (FDA)–approved pulsed current iontophoresis drug delivery system (FDA approval No. K042590, October 14, 2004, Transderm Ionto System, Mattioli Engineering, McLean, Va)… Experiments were performed on male Wistar rats (Harlan, Udine, Italy), age 6 to 8 months, weight 350 ± 50 g… Pulsed current iontophoresis was performed for 10 minutes following a standard procedure. Forty units per milliliter of BoNT/A was applied on all selected skin areas… Biopsy specimens were invesigated by immunohistochemical reactions… After iontophoresis, the neurotoxin was clearly detected in association with cutaneous striated skeletal muscle fibers localized in the deep dermis of rat's skin.