Transdermal transport of India ink by electromagnetic electroporation in Guinea pigs: an ultrastructural study

Transdermic administration by electroporation has developed over recent years for applying drugs in a variety of pathological processes. However, mechanisms are still not finally settled. India ink was applied to the backs of guinea pigs and for the transdermic transport short, high-voltage pulses (TDES, Dencort Dell) were administrated. Punch biopsies (4 mm) immediately taken after 24, 48, 72, 96 and at 26 days were studied by light and electronic microscopy. The ultrastructural characteristics and image pigment particles were reported. Particles of India ink were observed in the stratum corneum and in the epidermic keratinocytes of samples studied immediately after treatment. Particles were also seen in the epidermic and folicular keratinocytes, and in the papillary and reticular dermis (among collagen fibers, vessel walls, and macrophages) in all the subsequent biopsies; but not in the controls, which were conducted with electromagnetic waves alone. No tissue alterations were observed. The efficacy and noninvasive nature of electroporation for the transdermic administration of macromolecules is confirmed.