Transdermal Delivery of Macromolecules Using Skin Electroporation

Purposes. (1) To evaluate the feasibility of transdermal delivery ofmacromolecules by skin electroporation. (2) To assess the influenceof the molecular weight of the permeant on transport and examinewhether there exists a cut-off value of molecular weight. (3) Tolocalize the transport pathways of the macromolecules in the skin.Methods. FITC-dextran (FD) of increasing molecular weight (4.4, 12and 38 kDa) were used as model macromolecules to study the extentof transport across hairless rats skin in vitro and to localize theirdistribution in the skin by confocal scanning laser microscopy.Results. Electroporation enhanced the transport of the macromoleculesas compared to passive diffusion. The transdermal delivery by skinelectroporation of FITC and FD 4.4 was equivalent whereas transportof higher molecular weight FD was lower but significant. FITC and FD38 were observed in the epidermis both around and in the keratinocytes.Conclusions. Transdermal and topical delivery of macromolecules ofat least 40 kDa can be achieved by skin electroporation.