Characterisation of chemical composition and structural features of novel antimicrobial nanoparticles

© 2017 by the authors. Licensee MDPI, Basel, Switzerland. This is an open access article distributed under the Creative Commons Attribution License (CC BY 4.0) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Three antimicrobial nanoparticle types (AMNP0, AMNP1 and AMNP2) produced using the TesimaTM thermal plasma technology were investigated and their compositions determined using a combination of analytical methods. Scanning electron micrograph provided the morphology of these particles with observed sizes ranging from 10 – 50 nm. Whilst FTIR spectra confirmed the absence of polar bonds and organic impurities, strong Raman active vibrational bands at ca. 1604 and 1311 cm-1 ascribed to C-C vibrational motions were observed. Carbon signals resonated at δC126 ppm in solid state NMR spectra confirmed sp2 hybridised carbons were present in high concentration in two of the nanoparticle types (AMNP1 and AMNP2). X-ray powder diffraction suggested AMNP0 contains single phase WC in a high state of purity and multiple phases of WC/WC1-x were identified in both AMNP1 and AMNP2. Finally, XPS surface analyses revealed and quantified the elemental ratios in these composite formulations.Peer reviewe

Mebeverine-loaded electrospun nanofibers: physicochemical characterization and dissolution studies

Both fast dissolving and sustained release drug delivery systems (DDSs) comprising mebeverine hydrochloride (MB-HCl) embedded in either povidone (PVP) K60 or Eudragit® L 100-55 nanofibers have been prepared by electrospinning. The fibers are found to have cylindrical morphologies with smooth surfaces, except at high drug loadings that appear to induce surface roughness (PVP) or fragmentation (Eudragit). There is a general increase in fiber diameter with drug loading. Differential scanning calorimetry and X-ray diffraction demonstrate that the drug exists in an amorphous state in the fibers. Infrared spectroscopy data indicate that the drug has good compatibility with the polymer, whereas nuclear magnetic resonance spectroscopy and high-performance liquid chromatography analyses confirmed that the MB-HCl was not degraded during the spinning process. In vitro dissolution tests of the PVP fiber mats show them to dissolve within 10 s, an improved dissolution profile over the pure drug. The Eudragit fibers show pH-dependent drug release profiles, with only very limited release at pH 2.0 but sustained release over approximately 8 h at pH 6.8. The Eudragit nanofibers have the potential to be developed as oral DDSs for localized drug release in the intestinal tract, whereas the PVP materials may find the application as buccal delivery systems or suppositories

Tailoring the surface of polymeric nanofibres generated by pressurized gyration

Polymeric nanofibres with smooth, rough and porous surfaces were prepared by pressurised gyration, which is a novel method for producing nanofibres, utilising the combination of centrifugal spinning and solution blowing. A series of fibres were prepared by using polyacrylonitrile (Pan), poly(methyl methacrylate) (PMMA) and 50:50 Pan–PMMA polymer solutions without pressure and with 0·2 MPa working pressure. The surface morphology of the nanofibres was analysed by scanning electron microscopy, and their thermal properties were studied by thermogravimetry and hot-stage microscopy. Nanofibres with a smooth surface were generated at 0·2 MPa working pressure, and those with a rough surface were generated without any working pressure. Porous Pan nanofibres were prepared by using PMMA as a sacrificial polymer. The 50:50 Pan–PMMA blend fibres were subjected to heat treatment to obtain porous fibres. The less thermally stable PMMA decomposes when heated, generating pores on the surface of the Pan fibres. The porous nanofibres have a higher surface area-to-volume ratio compared to smooth fibres, and these fibres could be useful in a variety of applications, such as tissue engineering, filtering and purification