Modelling of solute transport across a temperature-sensitive polymer membrane

An important target of many controlled release systems is to properly modif y the drug release behaviour in response to some external stimuli like temp erature or pH changes. The copolymer gels made up by poly(N,N-dimethylamino ethyl methacrylate (DMAEMA)-co-acrylamide (AAm)), being thermosensitive, ar e suitable systems for the thermocontrol of the solute release. Modifying t he ratio DMAEMA/AAm, one may select the copolymer systems showing desired s welling properties. In order to better design such systems and in order to understand better the solute transport through the copolymer membrane, a ma thematical model has been developed. The model employs suitable flux equati ons for the water uptake or release and for the solute (hydrocortisone) dif fusion. With the condition of knowing the copolymer swelling kinetics, the model is able to describe in a reasonably good manner the solute transport across a DAEMA-AAm membrane undergoing step temperature changes. (C) 1999 E lsevier Science B.V. All rights reserved.