The release of nicotine from a hydrogel containing ion exchange resins

Parameters influencing the release rates of nicotine from a range of agar-based gel vehicles containing ion exchange resins to which the nicotine had been bound have been determined. Measurements were made using a Franz-type cell with transport across artificial and human skin membranes. Analysis of the data on the basis of feasible diffusion models show that the overall release process across Visking is best represented as being controlled by matrix diffusion through the hydrogel. Because the nicotine is bound to the resin its rate of release from the resin-containing gels is much less than that from the corresponding simple hydrogel. The availability of ions suitable to exchange with the nicotine. following their diffusion from the receptor buffer solution, is shown to substantially increase the delivery rate. The vehicles were found to be unsuitable for passive release across human skin. (C) 1998 Elsevier Science B.V. All rights reserved.