Analysis of skin permeation-enhancing mechanism of iontophoresis using hydrodynamic pore theory

Optimization of Iontophoretic Parameters for the Transdermal Delivery of Methotrexate

“…According to Manabe et al (2000), the pore size increases from 0.92 nm to 1.78 nm at low current density but when current is stopped, there is a reversibility wherein the pore size returns to its initial value and postiontophoresis flux returns to passive permeation levels. At higher current densities, the pore size was about 14.7 nm and it did not decrease even after the current was stopped.…”

Review of traditional and novel modalities that enhance the permeability of local therapeutics across the stratum corneum

“…Studies suggest a strong association between cationic drug delivery via electromigration and molecular size 55 . The enhancing effects of iontophoresis on the skin permeation of nonionic hydrophilic compounds can be explained by the increase in pore size and a higher solvent flow 56 . Diffusion shunts, including pores, hair follicles, and acrosyrigium, offer paths of reduced resistance for iontophoretic transport 57 .…”

Engineering Approaches to Transdermal Drug Delivery: A Tribute to Contributions of Prof. Robert Langer

“…The models relate skin permeability to the radius of the pore size and density in the skin. The pore radius in unperturbed skin has been found to be in the range of 20-30 Å [137,139,140,141,142,143,144,145,146,147,148,149]. The pore density has been proposed to range from 10 7 to 10 9 pores/cm 2 [150,151,152].…”