Modeling of drug release from swellable polymers

The water swelling and drug diffusion from initially hydrophilic, glassy polymer matrices were modeled using concentration-dependent diffusion equations for water and drug. The transport equation for water incorporated a relaxation-dependent mechanism. These equations were solved with an appropriate boundary condition incorporating a relaxation-dependent Deborah number. Experimental results from drug release from PVA and PHEMA samples were used to determine the validity of the model. (C) 2000 Elsevier Science B.V. All rights reserved.