Surface properties of semi-synthetic enteric coating films: Opportunities to develop bio-based enteric coating films for colon-targeted delivery

This study investigated the surface properties of the semi-synthetic enteric coatings materials for colon-targeted bioactive delivery. The enteric coating materials were prepared by combining nanoscale resistant starch, pectin, and carboxymethylcellulose. The surface properties of the coating materials were characterized by atomic force microscopy for barrier properties, physical stability, and the viscoelastic properties: the surface of the coatings was characterized in terms of root-mean square roughness (RMS), peak- to-valley height (Rz), surface skewness (Rsk), and surface kurtosis (Rku). The coating with pure nanoscale resistant starch was used as a control, which showed poor surface properties compared to the other films. However, the enteric coating films with nanoscale resistant starch: pectin 90:10 and nanoscale resistant starch: carboxymethylcellulose 10:90, showed very good barrier properties, visoelasticity, and physical stability. Therefore, the results of study suggest that the nanoscale resistant starch, pectin, and carboxymetylcellulose could be used to produce novel enteric coatings with good surface properties towards targeted delivery of bioactive compounds to the colon.