Electret enhances transdermal drug permeation.

Electrets are polymeric discs that carry semi permanent electrostatic charge. These provide electrostatic potentials in the range of 500 to 3,000 V. In the current work, the effect of electret exposure on the skin permeability was investigated. Transdermal transport studies were carried out across porcine epidermis in Franz diffusion cells. Salicylic acid, fluorescein labeled dextrans (FD) and propofol were used as test diffusants. The ability of electret to enhance the transdermal permeation of salicylic acid was studied in vivo in Sprague Dawley rats. Electret enhanced the permeability of porcine epidermis to salicylic acid. The enhancement factor increased with the surface voltage, however it was independent of the nature of charge (+ or -). The enhancement by electret was cut-off at 1 kDa, as interpreted by studying the transport of FD. The electrets decreased the permeability of skin to propofol, a lipophilic diffusant. Pretreatment of porcine epidermis enhanced the iontophoretic transport of salicylic acid, whereas the same did not enhance the transport of salicylic acid by electroporation. It is most likely that electret exposure renders the lipid domains of stratum corneum more permeable to polar molecules and in turn hampers the diffusion of nonpolar diffusant.