A mathematical model for release of biologics from porous hollow fibers

Abstract

The application of porous hollow fibers has recently been extended to the controlled release of biologics such as protein growth factors and lipid angiogenesis promoters. Release of these materials tends to occur more rapidly than would be predicted by conventional diffusion-based models of controlled release. Analysis of other modalities of transport as well as structural analysis of the controlled release system itself was performed to provide insight into the observed controlled release behavior from such systems. Specifically, it was discovered that osmotic-driven processes play a significant role in controlled release of proteins including vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). It was also found that the fiber pore microstructure and (more importantly) macrostructure influences release behavior. Model-guided design was implemented to adjust the physical properties of the fiber wall, leading to a release system that is better able to sustain the delivery of VEGF. This model may be used to more easily achieve a desired complex release behavior when used in combination with external regulation of the reservoir.

A new generation of hollow polymeric microfibers produced by gas dissolution foaming

“…4.c), which could suggest a lower degree of interaction with the water during the tests. Also, it is known that the morphology of the porous structure of a soluble scaffold or hollow fibers modifies their drug delivery capacity, by modifying the delivery mechanisms [26][27][28] , but in this case, the delivery mechanism does not seem to be altered. As the fiber mats kept their integrity, and the Ibuprofen is loaded into the PCL and not stored into the hollow structure or pores, the only delivery mechanism involved should be the diffusion of the Ibuprofen from the PCL fibers to the surrounding environment.…”

“…Among other applications, the tailoring of the porosity and structure of polymeric microfibers has been proposed to improve the drug delivery capability of such materials. [26][27][28] Both the dosage and delivery procedure of a therapeutic agent into our organism are known to be key parameters to provide highefficient and safe medical treatments. 29,30 However, most of the widely used conventional delivery systems (e.g., pills, tablets, drops, injections, etc.)…”