Numerical and analytical study of drug release from a biodegradable viscoelastic platform

A mathematical model to simulate drug delivery from a viscoelastic erodible matrix is presented in this paper. The drug is initially distributed in the matrix that is in contact with water. The entrance of water in the material changes the molecular weight, and bulk erosion can be developed depending on how fast this entrance is and how fast degradation occurs. The viscoelastic properties of the matrix also change in the presence of water as the molecular weight changes. The model is represented by a system of quasi-linear partial differential equations that take into account different phenomena: the uptake of water, the decreasing of the molecular weight, the viscoelastic behavior, the dissolution of the solid drug, and the delivery of the dissolved drug. Numerical simulations illustrating the behavior of the model are included. Copyright (c) 2015 John Wiley & Sons, Ltd.