Comparative evaluation of rivastigmine permeation from a transdermal system

24 25 In the present study, in vitro permeation experiments in a Franz diffusion cell were performed 26 using different synthetic polymeric membranes and pig ear skin to evaluate a rivastigmine 27 (RV) transdermal drug delivery system. In vitro-in vivo correlations (IVIVC) were examined 28 to determine the best model membrane. In vitro permeation studies across different synthetic 29 membranes and skin were performed for the Exelon Patch (which contains RV), and the 30 results were compared. Deconvolution of bioavailability data using the Wagner–Nelson 31 method enabled the fraction of RV absorbed to be determined and a point-to-point IVIVC to 32 be established. The synthetic membrane, Strat-M, showed a RV permeation profile similar 33 to that obtained with pig ear skin (R = 0.920). Studies with Strat-M resulted in a good and 34 linear IVIVC (R = 0.991) when compared with other synthetic membranes that showed R 35 values less than 0.90. The R2 for pig ear skin was 0.982. Strat-M membrane was the only 36 synthetic membrane that adequately simulated skin barrier performance and therefore it can 37 be considered to be a suitable alternative to human or animal skin in evaluating transdermal 38 drug transport, potentially reducing the number of studies requiring human or animal samples. 39 40