Preparation and characterization of pectin/chitosan beads containing porous starch embedded with doxorubicin hydrochloride: A novel and simple colon targeted drug delivery system

The objective of this study was to design a simple, colon targeted drug delivery system by using porous starch (PS), pectin and chitosan. Porous maize starch was prepared by hydrolysis with a combination of α-amylase and amyloglucosidase, and it was characterized by scanning electron microscopy, revealing the formation of porous structures in the starch granules. A Brunauer-Emmett-Teller (BET) specific surface area analysis indicated that the specific surface area of the PS (0.8768–0.9448 m2/g) was 19.88–21.42 times larger than that of native maize starch (0.0441 m2/g). The average pore diameter of the PS granules, as calculated by the Barrett-Joiner-Halenda (BJH) method, was 40.52–62.42 nm. A favorable adsorptive potential of the PS granules was verified by water and soybean oil tests. Doxorubicin was loaded into PS granules, which were then coated with a pectin/chitosan complex solution. The results of confocal laser scanning microscopy (CLSM) demonstrated that doxorubicin was successfully absorbed into the PS granules. In addition, an in vitro simulated digestion method demonstrated the effectiveness of this delivery design, as only a 13.80% release rate of doxorubicin was observed in the upper gastrointestinal tract, whereas release rates of 17.56% and 67.04% were observed for pectin/PS/doxorubicin and pectin/doxorubicin beads, respectively. It was concluded that the use of PS and a pectin/chitosan coating is an effective method for colon targeted drug delivery compared with the simple polysaccharide system.