Dual drug release electrospun core-shell nanofibers with tunable dose in the second phase.

This study reports a new type of drug-loaded core-shell nanofibers capable of providing dual controlled release with tunable dose in the second phase. The core-shell nanofibers were fabricated through a modified coaxial electrospinning using a Teflon-coated concentric spinneret. Poly(vinyl pyrrolidone) and ethyl cellulose were used as the shell and core polymer matrices respectively, and the content of active ingredient acetaminophen (APAP) in the core was programmed. The Teflon-coated concentric spinneret may facilitate the efficacious and stable preparation of core-shell nanofibers through the modified coaxial electrospinning, where the core fluids were electrospinnable and the shell fluid had no electrospinnability. The resultant nanofibers had linear morphologies and clear core-shell structures, as observed by the scanning and transmission electron microscopic images. APAP was amorphously distributed in the shell and core polymer matrices due to the favorite second-order interactions, as indicated by the X-ray diffraction and FTIR spectroscopic tests. The results from the in vitro dissolution tests demonstrated that the core-shell nanofibers were able to furnish the desired dual drug controlled-release profiles with a tunable drug release amount in the second phase. The modified coaxial electrospinning is a useful tool to generate nanostructures with a tailored components and compositions in their different parts, and thus to realize the desired functional performances.

Fast disintegrating quercetin-loaded drug delivery systems fabricated using coaxial electrospinning.

The objective of this study is to develop a structural nanocomposite of multiple components in the form of core-sheath nanofibres using coaxial electrospinning for the fast dissolving of a poorly water-soluble drug quercetin. Under the selected conditions, core-sheath nanofibres with quercetin and sodium dodecyl sulphate (SDS) distributed in the core and sheath part of nanofibres, respectively, were successfully generated, and the drug content in the nanofibres was able to be controlled simply through manipulating the core fluid flow rates. Field emission scanning electron microscope (FESEM) images demonstrated that the nanofibres prepared from the single sheath fluid and double core/sheath fluids (with core-to-sheath flow rate ratios of 0.4 and 0.7) have linear morphology with a uniform structure and smooth surface. The TEM images clearly demonstrated the core-sheath structures of the produced nanocomposites. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) results verified that quercetin and SDS were well distributed in the polyvinylpyrrolidone (PVP) matrix in an amorphous state, due to the favourite second-order interactions. In vitro dissolution studies showed that the core-sheath composite nanofibre mats could disintegrate rapidly to release quercetin within 1 min. The study reported here provides an example of the systematic design, preparation, characterization and application of a new type of structural nanocomposite as a fast-disintegrating drug delivery system.

Electrospun quercetin-loaded zein nanoribbons.

This study investigates quercetin-loaded zein nanoribbons, which were fabricated using different types of electrospinning processes. Using ethanol aqueous solutions as sheath fluids, the widths of quercetin-loaded zein nanoribbons (D, nm) could be manipulated simply through the adjustment of water contents(C) in the sheath fluids according to an equation of D=958-8.01C(r=0.9977), as indicated by the field emission scanning electron microscopic observations. X-ray diffraction and attenuated total reflectance Fourier transform infrared analysis suggested that the quercetin presented in the zein nanoribbons in an amorphous state due to their high compability resulted from hydrogen bonds. In vitro dissolution tests verified that nanoribbons from the coaxial process and single fluid process could provide drug sustained release profiles via a typical Fickian diffusion mechanism, and the former exhibited better performance than the later in terms of small initial burst effect and leveling-off release. Coaxial electrospinning with solvents can expand the capability of electrospinning in generating nanoproducts and provide a way for improving the nanoproducts' quality and functional performance.