Scientists from the South China University of Technology and The University of Queensland in Australia report that a system based on resistant starch acetate as a coating could resist digestion in the upper gastrointestinal tract, but degrade in conditions equivalent to those of the colon.
“The resistant starch acetate showed high digestion resistibility […] It can be applied as a potential film coating material for oral colon-targeting delivery system,” write researchers in the Journal of Agricultural and Food Chemistry.
“Importantly, for the resistant starch acetate film-coated pellets, a desired colon-targeting and release performance can easily be obtained by adjusting the film coating thickness as well as the plasticizer content of the coated resistant starch acetate film.
“Furthermore, the novel release system is suitable for loading a wide range of food bioactive components with different molecular weights and solubility,” they added.
Commenting independently on the findings, Winston Samuels, PhD, president and CEO of encapsulation experts Maxx Performance Inc., told NutraIngredients-USA.com that the delivery system has merit.
“My only challenge however is what happened when the bioactives with the coating around it that melts at 35 °C is exposed to environments that have higher temperatures,” he added.
The scientists produced micrometer-scale pellet cores using a technique called extrusion-spheronization. This produce pellets with cores ranging from 270 to 550 micrometers in diameter. Four different compounds were used as model bioactives, including 5-aminosalicylic acid, bovine serum albumin, hepatocyte growth-promoting factor (HGF), and insulin.
The pellets were coated with varying degrees of resistant starch acetate.
“By adjusting the degree of substitution, the coating thickness, and the plasticizer content of the resistant starch acetate film, either the pellets loaded with a small molecular bioactive component such as 5-aminosalicylic acid, or those with a macromolecular bioactive peptide or protein such as bovine serum albumin, hepatocyte growth-promoting factor, or insulin, showed a desirable colon-targeting release performance,” report the researchers.
Results in simulated gut fluids showed that only 12 percent of the bioactives were released in the simulated upper gastrointestinal tract, while up to 70 was released in the colonic fluid over a 40 hour period.
“This suggests that the delivery system based on resistant starch acetate film has an excellent colon targeting release performance and the universality for a wide range of bioactive components,” they concluded.
Source: Journal of Agricultural and Food Chemistry
Pubsliehd online ahead of print, ‘Just Accepted Manuscript’, doi: 10.1021/jf2005468
“An oral colon-targeting controlled-release system based on resistant starch acetate: synthetization, characterization and preparation of film-coating pellets”
Authors: H. Pu, L. Chen, X. Li, F. Xie, L. Yu, L. Li