Diffusion Models for Oral Drug Delivery to the Colon Using Porous Materials

Oral administration of drugs is patient-preferred due to ease of administration, less invasive procedures, and overall simplicity. However, traditional oral administration of drugs can lead to ineffective treatment and adverse side effects due to the physiological barriers of the gastrointestinal tract. Because of this, colon-specific drug delivery vehicles synthesized from polymeric, porous materials are being designed to control drug release to the colon. Specifically, these porous matrices include hydrogels, microgels/microparticles, and nanoparticle drug delivery systems. Furthermore, these formulations have been studied on their survivability and efficacy in delivery of the drugs to the colon. This review paper is focused on diffusion models for diffusion and drug release and how the choice of matrix material determines what drug release profiles are possible. Our goal is to provide a resource for identifying, applying, and advancing models for drug diffusion to the colon to help guide experimental design of drug delivery vehicles for intestinal pathologies.