Key Factors Controlling Linear Drug Release in Electrospun Fibers: Shape of the Cross-Section and Porosity

Electrostatically spun films are widely used as degradable drug carriers in in vivo drug delivery systems, such as overlay stents, due to their excellent surface area-to-volume ratio and ability to be modified. Researchers have long been devoted to modulating the structure and properties of drug-carrying films to achieve controllable and predictable drug release profiles. Currently, most prevalent methods involve blending different materials or adjusting the mixing ratio to achieve the desired release effect. In this paper, we propose a new strategy that does not rely on material blending. This strategy controls two key structural parameters of the electrospun film, namely cross-sectional shape and porosity, to achieve precise regulation of the drug release rate and release profile. The results demonstrate that both the drug release rate and total release amount of fibrous membranes with a rectangular cross-section are significantly higher than those of traditional circular cross-sections. Furthermore, the release rate of rectangular cross-sections can surpass that of circular ones by more than ten times under identical conditions. Additionally, increasing porosity enhances the specific surface area of drug films, significantly promoting drug diffusion and release. This work provides a theoretical basis for the thoughtful design of a biodegradable covered stents aimed at achieving sustained and linear drug release.