Preparation and characterization of nanostarch-based green hard capsules reinforced by cellulose nanocrystals

The green hard capsules were prepared with corn nano-starch (CNS) and cellulose nanocrystal (CNC) in this study, the glycerol and carrageenan were used as plasticizer and gelling agent in the CNS/CNC gel solution, respectively. The capsule-films with different CNC content were prepared by casting method, and the dipping method was used in preparation of the corresponding capsules. The compatibility of CNS/CNC capsules was analyzed by Fourier Transform Infrared spectroscopy (FTIR) and X-Ray Diffraction (XRD), and the morphology of the capsules was analyzed by Scanning Electron Microscopy (SEM). The results showed that the tensile strength of the CNS based capsule-film was significantly improved with the addition of CNC. When the content of CNC was 6.0%, the tensile strength increased by 238.10%. The transparency of the capsulewith different CNC contents was slightly reduced, but was greater than 87.0%. The loss on drying of CNS/CNC capsule was between 12.87% and 15.03%, and it could be completely dissolved in the artificial gastric juice within 6.0 min, which was in accordance with the provisions of Chinese Pharmacopoeia (2015). (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

This study prepared green hard capsules using corn nano-starch and cellulose nanocrystal, and found that the addition of cellulose nanocrystal can significantly improve the tensile strength of the capsules. Moreover, the transparency of the capsules slightly decreased, but still met the pharmacopoeia standards; the capsules showed good dissolution rate in artificial gastric juice.