Spatially constrained skin electroporation with sodium thiosulfate and
urea creates transdermal microconduits
Ilic L, Gowrishankar TR, Vaughan TE, Herndon TO, Weaver JC
JournaL of Controlled Release 61: (1-2) 185-202 AUG 27 1999
Controlled transport of molecules through the skin's main barrier, the
stratum corneum (SC), is a long standing goal of transdermal drug delivery.
Traditional, needle-based injection provides delivery of almost any water
soluble compound, by creating a single large aqueous pathway in the form
of the hollow core of a needle, through which drug is delivered by
pressure-driven flow. We extend previous work to show that SC-spanning
microconduits (here with diameters of about 200 mu m) can be created in
vivo by skin electroporation and low-toxicity, keratolytic molecules
(here sodium thiosulfate and urea). A single microconduit in isolated SC
can support volumetric flow of the order of 0.01 ml s(-1) by a pressure
difference of only 0.01 atm (about 10(2) Pa), demonstrating that the SC
barrier has been essentially eliminated within this microscopic area.