EO/EP copolymer membranes as reservoir in a transdermal therapeutic system for caffeine delivery: Modeling and simulation

The caffeine absorption/desorption properties of cross-linked membranes prepared from poly(ethylene oxide-co-epichlorohydrin) P(EO/EP) copolymers were determined in order to study the possibility to apply these elastomeric membranes as reservoir in transdermal therapeutic systems. The transport properties were simulated by using a series resistances model and considering the partition coefficient between the membrane and skin and a constant diffusion coefficient in both thin layers. From experimental and simulation results it was concluded that the main transport resistance is given by the skin but that the drug mass transfer could be enhanced by increasing the partition coefficient and the initial active molecule concentration in the membrane.