Zero-order drug release cellulose acetate nanofibers prepared using coaxial electrospinning

Novel drug-loaded cellulose acetate (CA) nanofibres were prepared by a modified coaxial electrospinning process, after which their zero-order drug release profiles were determined. Using 2 % (w/v) unspinnable CA solution as a sheath fluid, coaxial electrospinning can be conducted smoothly to generate ketoprofen (KET)-loaded CA nanofibres coated with a thin layer of blank CA. Scanning electron microscopy images demonstrated that nanofibres obtained from the modified coaxial process have a smaller average diameter, a narrower size distribution, more uniform structures, and smoother surface morphologies than those generated from single-fluid electrospinning. Transmission electron microscopy observations demonstrated that the nanofibres have a thin coating layer of blank CA on their surface with a thickness of ca. 15 nm. X-ray diffraction and differential scanning calorimetry verified that KET molecules in all of the nanofibres presented an amorphous state. Fourier transform infrared spectra demonstrated that CA has good compatibility with KET, which is brought about by hydrogen bonding. In vitro dissolution tests showed that the nanofibres coated with blank CA have no initial burst release effects and can provide a zero-order drug release profile over 96 h via a diffusion mechanism. The modified coaxial electrospinning method can provide new approaches in developing cellulose-based nano products with definite structural characteristics and improved functional performance.