This paper treats the drug release process as a phase-field problem and a phase-field model capable of simulating the dynamics of multiple moving fronts, transient drug fluxes, and fractional drug release from swellable polymeric systems is proposed and validated experimentally. The model can not only capture accurately the positions and movements of the distinct fronts without tracking the locations of fronts explicitly but also predict well the release profile to the completion of the release process. The parametric study has shown that parameters including water diffusion coefficient, drug saturation solubility, drug diffusion coefficient, initial drug loading ratio, and initial porosity are critical in regulating the drug release kinetics. It has been also demonstrated that the model can be applied to the study of swellable filaments and has wide applicability for different materials. Due to explicit boundary position tracking being eliminated, the model paves the way for practical use and can be extended for dealing with geometrically complex drug delivery systems. It is a useful tool to guide the design of new controlled delivery systems fabricated by fused filament fabrication.
Keywords: drug delivery system; drug-loaded filament; fused filament fabrication; phase-field model; swellable polymer.