Optimization and release characteristics of catechin-loaded calcium pectinate beads by internal gelation

The aim of this study was to optimize the composition of catechin-loaded calcium pectinate gel (CPG) beads formed using internal gelation and to evaluate the sustained-release behavior of catechin. The pectin concentration, catechin-to-pectin ratio, and calcium carbonate-to-pectin ratio were optimized for the sustained catechin release (2.89, 28.92, and 32.79%, respectively). The catechin release profiles were analyzed using the simple enzyme kinetic-like semi empirical model newly proposed in this study. The actual release rate was found to be the fastest in the simulated intestinal fluid (SIF), followed by the simulated gastric fluid (SGF) and the pH 4.5 buffer, whereas the thermodynamic equilibrium was achieved fastest in the pH 4.5 buffer, followed by SGF and SIF. Glutaraldehyde treatment suppressed catechin release in all tested media. These results suggest that internally gelled CPG beads are suitable for catechin delivery, and crosslinkers, such as glutaraldehyde, can effectively sustain their release.