On the ability of chromatographic mass balance to predict solute diffusivity in drug delivery systems

Abstract

The ability to predict the drug diffusion coefficient within hydrogel-based drug delivery devices has a pivotal role in the design of these materials. In the last years, many mathematical models have been developed, but they often rely on fitted parameters with a consequent limitation in terms of prediction. Indeed, they are mainly centered on the pure Fickian diffusion together with degradation and swelling contributions. However, especially with a drug concentration typical of pharmacological treatments, several other mechanisms such as drug-polymer and drug-drug interactions cannot be neglected. In this work, we checked the ability of a simple mathematical model to estimate diffusion coefficients of drugs loaded within hydrogel considered as a chromatographic stationary phase. Mathematical modeling satisfactorily matched with different sets of literature data proving that our assumptions are able to describe the key phenomena governing the device's behavior.