Effect of entrapped alpha-tocopherol on mucoadhesivity and evaluation of the release, degradation, and swelling characteristics of zein-chitosan composite electrospun fibers

A gastro-mucoadhesive matrix of ultrafine fibers was formed from composite polymers of zein, poly(ethylene oxide), and chitosan at a ratio of 87.5/10/2.5 via electrospinning. Alpha-tocopherol (alpha-TOC), a hydrophobic compound, was embedded at 20 wt% into the fiber matrix to investigate its effects on fiber morphology and mucoadhesivity. alpha-TOC release characteristics were examined in simulated gastric fluid (SGF) at pH 1.2 with pepsin and SGF at pH 2 without pepsin at 37 +/- 0.5 degrees C. Gastro-mucoadhesivity was tested in porcine gastric mucosa. Fiber morphology was characterized by scanning electron microscopy (SEM). alpha-TOC did not affect fiber morphology, but significantly enhanced mucoadhesivity (p < 0.05). alpha-TOC release in SGF at pH 1.2 with pepsin was triggered by erosion, and alpha-TOC release in SGF at pH 2 without pepsin was triggered by swelling, and driven by diffusion. SEM micrographs revealed that the fibers lost their fibrous structure and later fused, minimizing the fibrous film release surface area. (C) 2013 Elsevier Ltd. All rights reserved.