Evaluation of mechanical and thermal properties of carrageenan/hydroxypropyl methyl cellulose hard capsule

Abstract

The inherent source of gelatin used for commercial hard capsules causes a surging demand for vegetarian capsules. In this work, carrageenan is utilized in preparing hard capsules to meet consumer preferences. Hydroxypropyl methylcellulose (HPMC) was incorporated as a reinforcing agent to improve the low mechanical properties of hard capsules made of carrageenan. The HPMC concentration was manipulated from 0.2 to 1.0 w/v% in the carrageenan matrix. The increasing concentration of HPMC exerts significant effects on the tensile strength and elongation at break, with an improvement of 59.1% and 46.9%, respectively, at the optimized HPMC concentration of 0.8 w/v%. The loop strength of the capsule is also increased by 56.4% with decreasing moisture content. The downfield movement from around 3.20 ppm of the carrageenan proton to 3.33 ppm in the proton nuclear magnetic resonanance ( 1H‐NMR) spectrum suggests the formation of intermolecular hydrogen bonding between carrageenan and HPMC, which correlates to the results of Fourier‐transform infrared spectroscopy (FTIR) and zeta potential. The glass transition temperature of the film was increased from 37.8 to 65.3°C, showing an upgrade in thermal stability. The film possesses a major mass loss with an activation energy of 64.7 kJ/mol with an increment of 43.4% compared to the control carrageenan. These findings support the conclusion that HPMC enhanced the mechanical properties and thermal stability of the carrageenan film, and the comprehensive analysis of the molecular interaction and decomposition kinetics subsequently may expand the application fields of the carrageenan‐HPMC hard capsule as an alternative to gelatin in the future.

Enhancing Pullulan Soft Capsules with a Mixture of Glycerol and Sorbitol Plasticizers: A Multi-Dimensional Study

“…Currently, the film-forming agents in the plant-based capsules include three categories: cellulosic fat (such as hydroxypropyl methylcellulose [ 8 ], carboxymethyl cellulose [ 13 ], nanocrystalline cellulose [ 14 ], etc. ), polysaccharides (such as pullulan [ 15 ], carrageenan [ 16 ], etc. ), and starch (such as modified corn starch [ 11 ], potato starch, etc.).…”

Mechanical and Thermal Evaluation of Carrageenan/Hydroxypropyl Methyl Cellulose Biocomposite Incorporated with Modified Starch Corroborated by Molecular Interaction Recognition

“…The properties of hard capsules in terms of mechanical and thermal are hypothesized to be enhanced owing to the formation of intermolecular hydrogen bonding between carrageenan and CMSS. The carrageenan biocomposite with the inclusion of HPMC was proven to increase the tensile strength and the thermal activation energy up to 56 and 43%, respectively . The formation of hydrogen bonds is a key component of chemical structure, conformation, and reactivity. − Thus, detection of hydrogen bonds remains an area of active research.…”

“…The carrageenan biocomposite with the inclusion of HPMC was proven to increase the tensile strength and the thermal activation energy up to 56 and 43%, respectively. 37 The formation of hydrogen bonds is a key component of chemical structure, conformation, and reactivity. 38−40 Thus, detection of hydrogen bonds remains an area of active research.…”