Numerical modeling and simulation for microneedles drug delivery: A novel comprehensive swelling-obstruction-mechanics model

Hydrogel microneedles have attracted significant attention in drug delivery due to their non-invasiveness and efficient administration. However, a thorough understanding of the drug transport mechanism is essential to achieve controlled drug delivery and geometry optimization of microneedles. In this study, a new swelling-obstruction-mechanics model is presented to describe the swelling and drug release behavior of hydrogel microneedles. The model integrates the swelling kinetics, the obstruction scaling of drug molecules, and the mechanical properties of hydrogel and skin and reveals the effects of swelling of the microneedle matrix and drug molecules on drug release. Subsequently, numerical simulations were conducted using the model, which enabled the optimization of hydrogel microneedle design parameters by adjusting the input variables. The results show that the geometric parameters of microneedles, especially the cross-sectional shape, have a significant effect on the drug release performance. Nevertheless, the parameters affect each other and need to be considered in the selection of a variety of factors. Additionally, penetration depth significantly affects drug release efficiency, highlighting the need for auxiliary application devices. In summary, the model advances both theoretical understanding and practical design of hydrogel microneedles, identifying key factors in drug release and optimizing their efficiency and reliability for clinical applications.