Transdermal iontophoresis drug concentration

Riviere, J. E., Monteiro-Riviere, N. A., and Inman. A. Determination of lidocaine concentrations in skin after transdermal iontophoresis Effects of vasoactive drugs. Pharm. Res. 9 211, 1992. 

Transdermal delivery is suitable for small, generally lipophilic, potent molecules that require low input rates to achieve effective plasma concentrations. There may be a slow rate of increase of concentration if the drug forms a depot in the skin. Depot formation will also result in a slow decrease in concentration when the system is removed from the skin. These disadvantages can be overcome by the use of iontophoresis, by which the molecules are actively carried across the skin by a small electrical current. This provides a faster and more controllable transfer of drug. Intramuscular/Subcutaneous... 

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