Numerical Simulation of Swelling and Drug Release Processes for Weak Polyelectrolyte Hydrogels

Based on the three-phase model, a mathematical model of swelling and drug release for weak polyelectrolyte hydrogels was established by combination of Langmuir isothermal adsorption equation and drug release equation; the finite element method was adopted to investigate the influence of the material parameters on swelling and drug release in the case of drugs were distributed within the weak polyelectrolyte hydrogels homogeneously; the mechanism of drugs released from weak polyelectrolyte hydrogels in different moments was analyzed as well; then the impacts of drug distribution conditions within the hydrogels which consist of homogeneous distribution and inhomogeneous distribution on swelling and drug release were compared comprehensively, and it has been found that drug release process is consistent with zero order release kinetics when drugs presented the sine distribution in the hydrogels; finally, the simulated results were comparatively compared with Beebe' s experimental results to validate the accuracy of this simulation.