simulation of drug release in a polymer screw

In recent years, research in the field of pharmaceutical sciences has led to the design of drugs for various diseases. but for the treatment of some diseases, drugs with high side effects and low efficiency are used. designing targeted drug release systems is one of the solutions to this problem. these systems can deliver a controlled amount of drug to the target cell or tissue. in this paper, drug release was simulated in a screw model designed in comsol software for orthopedic applications. the purpose of this simulation is to investigate the distribution of the drug concentration on the screw in the surrounding chamber over time. to simulate drug release in a fluid, navier-stokes equations for incompressible fluid are used for fluid velocity and pressure, as well as mass transfer equations for the drug concentration distribution. a tetrahedral mesh is used for meshing the model. this simulation is performed in a time-dependent manner for 72 hours with time steps of 0.1 hours. the equations have been solved directly with the pardiso solver. the obtained results show that drug distribution changes exponentially. as can be seen, the first release of the drug was incremental to 50 hours, and after the release amount, it reached a constant and maximum value.