Long-term in vitro study of paclitaxel-eluting bioresorbable core/shell fiber structures

Paclitaxel-eluting bioresorbable core/shell fiber structures for stent applications and local cancer treatment were developed and studied. These structures were composed of a polyglyconate core and a porous PDLGA shell loaded with the anti-proliferative agent paclitaxel, prepared using freeze drying of inverted emulsions. The investigation of these new composite fibers focused on the effects of the emulsion's composition (formulation) and process kinetics on the long-term drug release from the fibers, in light of the shell's morphology and degradation profile. Paclitaxel release from the porous shell was relatively slow due to its extremely hydrophobic nature. It exhibited three phases of release, which corresponded to the degradation profile of the host PDLGA. We found that the effect of the emulsion formulation on the release profile is more significant than the effect of the process kinetics. The copolymer composition had the most dominant effect on the drug release profile from the composite fibers. The polymer content also affected the release profile, whereas the drug content and the organic:aqueous phase ratio resulted in minor effects. Emulsions with a less hydrophobic nature are favorable for effective controlled release of the hydrophobic paclitaxel from the porous shell.