Hybrid Electrospun Polycaprolactone Mats Consisting of Nanofibers and Microbeads for Extended Release of Dexamethasone.
PURPOSE
We designed electrospun polycaprolactone mats consisting of nanofibers and microbeads for extended delivery of dexamethasone.


METHODS
Thin flexible dexamethasone loaded polycaprolactone mats were prepared by electrospinning. The solvents, polymer loading, voltage and tip-to-collector distance were varied to explore the effects on microstructure of the mats. The microstructure was determined by scanning electron microscope imaging; drug transport was measured and modeled, and X-ray diffraction was used to gauge the crystallinity. Drug transport and X-ray diffraction studies were also conducted with a spin cast film for comparison.


RESULTS
Thin mats, about 10 μm in thickness, were prepared by electrospinning. By controlling the voltage and tip-to-collector distance, we achieved a hybrid structure comprising of nanorods (nanofibers) and microbeads. The release profiles were fitted to the diffusion equation to obtain the diffusivities in the spheres and the rods. The diffusivity in the electrospun nanofibers was significantly lower compared to the casted films due to increased crystallinity, which was estimated from X-ray diffraction analysis. The electrospun hybrid mats sustained drug release for the desired duration of a month, in spite of the small thickness of about 10 μm. By comparison, a ten-fold thicker cast film sustains release for about the same duration suggesting about 100-fold decrease in diffusivity in the electrospun mats due to increased crystallinity.


CONCLUSIONS
Electrospun polycaprolactone mats are optimal for achieving long release durations due to increased crystallinity. Designing a hybrid structure by controlling the electrospinning parameters can be a useful approach to increase the release durations.
['Hsu|Kuan-Hui|KH|', 'Fang|Sheng-Po|SP|', 'Lin|Chang-Lin|CL|', 'Liao|Yan-Shin|YS|', 'Yoon|Yong-Kyu|YK|', 'Chauhan|Anuj|A|']
D003460:Crystallization D003692:Delayed-Action Preparations D003907:Dexamethasone D004058:Diffusion D004337:Drug Carriers D004339:Drug Compounding D005938:Glucocorticoids D007700:Kinetics D008855:Microscopy, Electron, Scanning D008956:Models, Chemical D057139:Nanofibers D050997:Nanomedicine D011091:Polyesters D012995:Solubility D012997:Solvents D013678:Technology, Pharmaceutical D014961:X-Ray Diffraction
polycaprolactone nanofibers microbeads extended release electrospinning