Abstract: AIMTo establish a mathematical model describing drug transdermal permeation under electroporation and analyze influence of electric pulse upon the course of transdermal permeation. METHODSUsing caffeine as a model drug, measure permeation fluxes under different pulse strengthes (voltage and pulse numbers, etc.), set up an approximately mathematical model with quick-slow responding passages. RESULTSAssuming that only the maximal increment of diffusion coefficient in the passage with slow responding (D₁), and maximal effective area fraction in the passage with quick responding (a₂), are the conditionally dependent parameters. It is found that the fitted difference from the model to the data is far smaller than the repeated experiment errors, and the linear correlation coefficients between the two parameters and total energy of pulses, E, are 0.955 (P=0.00) and 0.924 (P=0.00), respectively. CONCLUSIONThe data is finely fitted by the model. The modeling methodology and the hypotheses about the Ficken diffusion law and the double passages with quick-slow respondings both may be accepted. It may be considered that the two parameters, D₁ and a₂ are conditionally dependent and others are independent.