Improvement of stability and release of (-)-epicatechin by hot melt extrusion

Abstract

Besides its poor dissolution in polymers, the stability, and bitterness of (-)-epicatechin present challenges for additional developments. Polymer formulations rich in flavonoids or other antioxidants can be developed by hot melt extrusion (HME) for enhancement of stability, release, and taste masking. The formulations are extruded at a temperature substantially below the melting point of (-)-epicatechin to avoid its degradation. The corresponding compound consists of about 50% wt. of an active nutraceutical ingredient, in this case (-)-epicatechin, and food grade polymers (GRAS: generally recognized as safe). In order to identify possible chemical or physical changes in the formulations, they were characterized using various techniques, such as differential scanning calorimetry, thermogravimetric analysis, polarized optical microscopy, in vitro release profile, sensory analysis, high-performance liquid chromatography, and Fourier transform infrared spectroscopy. The crystallinity of (-)-epicatechin was reduced after melt extrusion, but its chemical structure remained unchanged. The main contribution of this research is to shed light on the preparation of polymeric formulations based on (-)-epicatechin using HME as an encapsulation technique to improve stability, release, and taste masking, which may be scaled up and commercially launched as nutraceutical products. © 2019 Walter de Gruyter GmbH, Berlin/Boston.