Preparation of an ascorbic acid/PVA-chitosan electrospun mat: a core/shell transdermal delivery system

Core/shell L-ascorbic acid/poly(vinyl alcohol)-chitosan (ASC/PVA-CS) nanofibers were successfully prepared utilizing coaxial electrospinning and their characteristics were compared with monolithic blend PVA-CS-ASC nanofibers. In coaxial electrospinning, a series of aqueous acetic acid solutions of PVA-CS were used as a shell solution and a variety of ASC concentrations in a stabilizing solvent (ethanol/propylene glycol/water) were utilized as a core solution. Characterization of the obtained nanofibers was followed by SEM and TEM. Results of the SEM showed that an increase in PVA concentration in the shell solution or ASC concentration in the core solution increases the average diameter of nanofibers and leads to smooth morphologies. Furthermore, coaxial architecture of nanofibers was investigated and confirmed by differential thermal analysis (DTA) and X-ray diffraction (XRD). A release study indicated that a higher concentration of CS in the shell part of the crosslinked coaxial nanofibers leads to a decreased release rate of the ASC. Also, a lower concentration of ASC in the core part decreases the drug release from the core/shell nanofibers.