On the Road to Development of an in Vitro Permeation Test (IVPT) Model to Compare Heat Effects on Transdermal Delivery Systems: Exploratory Studies with Nicotine and Fentanyl

Purpose At elevated temperatures, the rate of drug release and skin permeation from transdermal delivery systems (TDS) may be higher than at a normal skin temperature. The aim of this study was to compare the effect of heat on the transdermal delivery of two model drugs, nicotine and fentanyl, from matrix-type TDSs with different formulations, using in vitro permeation tests (IVPT). Methods IVPT experiments using pig skin were performed on two nicotine and three fentanyl TDSs. Both continuous and transient heat exposures were investigated by applying heat either for the maximum recommended TDS wear duration or for short duration. Results Continuous heat exposure for the two nicotine TDSs resulted in different effects, showing a prolonged heat effect for one product but not the other. The J max enhancement ratio due to the continuous heat effect was comparable between the two nicotine TDS, but significantly different ( p