Characterisation of resistant starch from <i>Vigna unguiculata</i> for the development of an oral‐colon delivery agent

Abstract

Summary There is a significant concern associated with the delivery of chemotherapeutics to the colon due to limited drug absorption in the gastrointestinal tract. Starch has received great interest as a delivery agent owing to its cost efficacy and high availability. In this study, native resistant starch and acid‐modified resistant starch from Vigna unguiculata were used to produce microcapsules containing camptothecin as an oral‐colon‐specific drug delivery agent. Functional characteristics such as solubility, swelling power, amylose content, emulsifying, foaming together with water and oil absorption capacity of native resistant starch and acid‐modified resistant starch were established. The prepared microcapsules were characterised and subjected to simulated digestion with the obtained residue evaluated for cytotoxicity using the MTT assay. It was observed that acid‐modified resistant starch had the best functional properties (water absorption capacity: 2.76 g g −1 , oil absorption capacity: 3.13 g g −1 , amylose: 35%, foaming capacity: 17.73%, and emulsifying activity: 33.33%) as compared to its native resistant starch (water absorption capacity: 2.03 g g −1 , oil absorption capacity: 2.81 g g −1 , amylose: 32%, foaming capacity: 4% and emulsifying activity: 23.56%). The microcapsules had a particle size of 0.25–0.35 μm, moisture content between 1.12% and 3.41% and a high encapsulation efficiency of 96.40 and 98.96% for native resistant starch and acid‐modified resistant starch capsules respectively. Results for MTT assay showed cancerous cells to be inhibited by microcapsules with noncancerous cells less affected.