The Optimized Fabrication of a Polymeric Porous Microneedle for Effective Iontophoresis

摘要

Iontophoresis has been widely studied to improve transdermal drug administration and transdermal extraction of interstitial fluids without patient' stress. The stratum corneum (SC), outermost layer of skin, has the barrier functions preventing contamination of harmful molecules into a body, and also hinders the iontophoresis due to its high electrical resistance. Previously, we have reported the porous microneedle (PMN) prepared by a molding process and porogen method, which has a potential to lower the total resistance of the skin and improves the effect on iontophoresis. However, the reproducibility of PMN's porosity had room for further improvement since the solution of porogen used in the previous method could evaporate and change its volume. Here, we studied a few kinds of porogen solution with different boiling point to create the PMN with higher reproducibility. Furthermore, the ionic resistance of the electrolyte-containing PMN and that of the skin with the PMN were evaluated in order to design an efficient iontophoretic PMN patch.