Sustained release properties of cross‐linked corn starches with varying amylose contents in monolithic tablets

Abstract

AbstractCorn starches of varying amylose contents (0, 28, and 70%) were cross‐linked with epichlorohydrin to different levels (0.01, 0.05, and 0.1% w/w starch dry basis), and their sustained release properties in tablets were evaluated using propranolol hydrochloride as the model drug. Drug release was correlated with swelling power of the cross‐linked starches, porosity of tablets, and rheological properties of the swollen tablets. Cross‐linking increased the drug release rate from starch tablets, and had a stronger impact on amylose‐containing starch matrices than on waxy corn starch ones. The cross‐linked starches showed lower swelling power and produced tablets of lower porosity than their respective non‐cross‐linked controls. Increasing cross‐linking led to progressively more rigid and stiffer waxy corn starch matrices, but it had the opposite effect on high amylose corn ones, and an intermediate effect on common corn ones. The amylose content played an important role in the properties of starch matrices, and consequently the sustained release and rheological behavior of starch tablets.