Synergistic effect of enhancers for transdermal drug delivery

Transdermal drug delivery offers a non-invasive route of drug administratio n, although its applications are limited by low skin permeability. Various enhancers including iontophoresis, chemicals, ultrasound, and electroporati on have been shown to enhance transdermal drug transport. Although all thes e methods have been individually shown to enhance transdermal drug transpor t, their combinations have often been found to enhance transdermal transpor t more effectively than each of them alone. This paper summarizes literatur e studies on these combinations with respect to their efficacy and mechanis ms.