A two-phase controlled drug release model in a one-compartmental system

Small intestine is the main absorptive organ of orally consumed drugs in the body. Hydrogel is one of the materials that commonly used as a controlled drug release device that able to deliver drugs to be absorbed in the small intestine. This material swells to enable the drug release, leading to a dynamic diffusivity. In this paper, we aimed to simulate the controlled drug release from a swelling hydrogel considering the dynamic diffusion coefficient in a one-compartmental system of small intestine. The small intestine is considered as a single compartment where the controlled drug release process takes place simultaneously with the drug absorption and elimination process. We had formulated a two-phase controlled drug release model with two different constant diffusion coefficients using the advection-diffusion equation. The two-phase model was then adapted into the one-compartmental system and is solved using the forward finite difference method. The numerical simulation shows that the suggested mathematical model able to express the complex process of the controlled drug delivery in the small intestine.