title: Electrospun medicated shellac nanofibers for colon-targeted drug delivery.
abstract: Medicated shellac nanofibers providing colon-specific sustained release were fabricated using coaxial electrospinning. A solution of 7.5 g shellac and 1.5 g of ferulic acid (FA) in 10 mL ethanol was used as the core fluid, and a mixture of ethanol and N,N-dimethylformamide (8/10 v/v) as the shell. The presence of the shell fluid was required to prevent frequent clogging of the spinneret. The diameters of the fibers (D) can be manipulated by varying the ratio of shell to core flow rates (F), according to the equation D=0.52 F(-0.19). Scanning electron microscopy images revealed that fibers prepared with F values of 0.1 and 0.25 had linear morphologies with smooth surfaces, but when the shell fluid flow rate was increased to 0.5 the fiber integrity was compromised. FA was found to be amorphously distributed in the fibers on the basis of X-ray diffraction and differential scanning calorimetry results. This can be attributed to good compatibility between the drug and carrier: IR spectra indicated the presence of hydrogen bonds between the two. In vitro dissolution tests demonstrated that there was minimal FA release at pH 2.0, and sustained release in a neutral dissolution medium. The latter occurred through an erosion mechanism. During the dissolution processes, the shellac fibers were gradually converted into nanoparticles as the FA was freed into solution, and ultimately completely dissolved.
authors.affiliation: School of Materials Science & Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Wang
authors.affiliation: School of Materials Science & Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093, China. Electronic address: ydg017@usst.edu.cn.
authors.forename: Deng-Guang
authors.initials: DG
authors.lastname: Yu
authors.affiliation: School of Materials Science & Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093, China.
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Li
authors.affiliation: Faculty of Science and Technology, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK.
authors.forename: S W Annie
authors.initials: SW
authors.lastname: Bligh
authors.affiliation: UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, UK. Electronic address: g.williams@ucl.ac.uk.
authors.forename: Gareth R
authors.initials: GR
authors.lastname: Williams
mesh_terms: D002152:Calorimetry, Differential Scanning / Q000379:methods; D003106:Colon / Q000187:drug effects*; D004126:Dimethylformamide / Q000737:chemistry; D004337:Drug Carriers / Q000737:chemistry; D016503:Drug Delivery Systems / Q000379:methods; D006860:Hydrogen Bonding; D008855:Microscopy, Electron, Scanning / Q000379:methods; D057139:Nanofibers / Q000008:administration & dosage* / Q000737:chemistry*; D012116:Resins, Plant / Q000008:administration & dosage* / Q000737:chemistry*; D012995:Solubility; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D004337:Drug Carriers; D012116:Resins, Plant; C003934:shellac; D004126:Dimethylformamide
keywords: Coaxial electrospinning; Colon-targeted release; Erosion mechanism; Medicated nanofibers; Shellac