Iontophoresis delivery efficiency

Jadoul and Preat [56] have also proposed a similar explanation for the lack of synergistic effects on transdermal delivery of domperidone with combined electroporation (1 pulse of 1000 V with a time constant of 4 ms) and iontophoresis (0.4 mA/cm2) despite the fact that iontophoresis was switched on within a few seconds after electroporation. Combined pulsing and iontophoresis also did not improve penetration of sodium nonivamide acetate through nude mouse skin [51], Therefore, when combing the two protocols, it should be more efficient to use a system that delivers current during or immediately after pulsing without delay. 

Safe and effective delivery of peptides has also been successfully demonstrated in human studies using iontophoresis, a technique that uses mild electric current to facilitate transport of molecules across the skin. ° Iontophoresis works primarily by a combination of two forces, electro-repulsion of charged drug molecule away from the electrode and into the skin, and electroosmosis, a convective solvent flow in the direction of the counter-ion transport. In general, cationic proteins and peptides are delivered more efficiently than anionic molecules because electro-osmosis works in the same direction as electro-migration for cationic species. 

During recent years, the topical delivery of liposomes has been applied to different applications and in different disease models (188). Current efforts in this area concentrate around optimization procedures and new compositions. Recently, highly flexible liposomes called transferosomes that follow the trans-epidermal water activity gradient in the skin have been proposed. Diclofenac in transferosomes was effective when tested in mice, rats and pigs (189). The concept of increased deformability of transdermal liposomes is supported by the results of transdermal delivery of pergolide in liposomes, in which elastic vesicles have been shown to be more efficient (190).The combination of liposomes and iontophoresis for transdermal delivery yielded promising results (191, 192). 

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