The present study reports zero-order controlled release drug-loaded nanofibers fabricated using a modified coaxial electrospinning,in which a 2% (weight/volume) dilute solution of polyacrylonitrile (PAN) was exploited as a sheath fluid.With PAN and acyclovir (ACY) as the filament-forming matrix and active pharmaceutical ingredient,respectively,the prepared nanofibers are of linear morphologies and clear core-sheath structures,which were verified by electron microscopic observations.X-ray diffraction tests demonstrate that ACY presents in the PAN matrix in an amorphous status.In vitro dissolution tests show that near 80% of the contained ACY in the nanofibers is freed in a zero-order manner without initial burst effect.