title: Hybrid Electrospun Polycaprolactone Mats Consisting of Nanofibers and Microbeads for Extended Release of Dexamethasone.
abstract: We designed electrospun polycaprolactone mats consisting of nanofibers and microbeads for extended delivery of dexamethasone.
  
  
  
  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.
  
  
  
  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.
  
  
  
  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.
authors.affiliation: Chemical Engineering, University of Florida, Gainesville, Florida, 32611-6005, USA.
authors.forename: Kuan-Hui
authors.initials: KH
authors.lastname: Hsu
authors.affiliation: Electrical and Computer Engineering, University of Florida, Gainesville, Florida, 32611, USA.
authors.forename: Sheng-Po
authors.initials: SP
authors.lastname: Fang
authors.affiliation: Material Science and Engineering, University of Florida, Gainesville, Florida, 32611, USA.
authors.forename: Chang-Lin
authors.initials: CL
authors.lastname: Lin
authors.affiliation: Material Science and Engineering, University of Florida, Gainesville, Florida, 32611, USA.
authors.forename: Yan-Shin
authors.initials: YS
authors.lastname: Liao
authors.affiliation: Electrical and Computer Engineering, University of Florida, Gainesville, Florida, 32611, USA.
authors.forename: Yong-Kyu
authors.initials: YK
authors.lastname: Yoon
authors.affiliation: Chemical Engineering, University of Florida, Gainesville, Florida, 32611-6005, USA. Chauhan@che.ufl.edu.
authors.forename: Anuj
authors.initials: A
authors.lastname: Chauhan
mesh_terms: D003460:Crystallization; D003692:Delayed-Action Preparations; D003907:Dexamethasone / Q000008:administration & dosage / Q000737:chemistry*; D004058:Diffusion; D004337:Drug Carriers; D004339:Drug Compounding; D005938:Glucocorticoids / Q000008:administration & dosage / Q000737:chemistry*; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D008956:Models, Chemical; D057139:Nanofibers; D050997:Nanomedicine; D011091:Polyesters / Q000737:chemistry*; D012995:Solubility; D012997:Solvents / Q000737:chemistry; D013678:Technology, Pharmaceutical / Q000379:methods; D014961:X-Ray Diffraction
chemical_list: D003692:Delayed-Action Preparations; D004337:Drug Carriers; D005938:Glucocorticoids; D011091:Polyesters; D012997:Solvents; C016240:polycaprolactone; D003907:Dexamethasone
keywords: electrospinning; extended release; microbeads; nanofibers; polycaprolactone