KINETIC EVALUATION OF TRANSDERMAL NICOTINE DELIVERY SYSTEMS

The skin permeation and release kinetics of nicotine from four nicotine-releasing transdermal delivery systems (TDS) marketed recently was investigated under identical conditions to evaluate the effect of system design and the interchangeability of these products. In the study, hairless rat skin was first used as an animal model to evaluate the permeation mechanisms of various TDS's, which were then verified by studying the permeation through human cadaver skin. Three of the four TDS's were found to deliver nicotine at zero(th)-order permeation kinetics at steady state with permeation rate ranging from 0.072 - 0.197 mg/cm2/hr, while the fourth one produced a triphasic zero(th)-order permeation rate profile. Three TDS's released nicotine at non-linear manner, which could be described by a linear Q vs. t1/2 relationship, while one TDS yielded a constant release at steady state. The different skin permeation profiles of nicotine delivered by these TDS's could be explained by the difference in their system designs and structural compositions.