Sodium alginate/carboxymethyl starch/κ-carrageenan enteric soft capsule: Processing, characterization, and rupture...

Area of Science:

• Materials Science
• Pharmaceutical Technology
• Polymer Chemistry

Background:

• Gelatin soft capsules have limitations, necessitating the development of alternative materials.
• Plant-derived polymers are being explored as sustainable and functional substitutes for gelatin.

Purpose of the Study:

• To investigate sodium alginate (SA), carboxymethyl starch (CMS), and κ-carrageenan (κ-C) as matrix materials for soft capsules.
• To optimize the blend ratio for enhanced mechanical and degradation properties.
• To develop a plant-based enteric soft capsule alternative to gelatin.

Main Methods:

• Rheological screening of co-blended polymer solutions.
• Film characterization using thermogravimetry, SEM, FTIR, X-ray, water contact angle, and mechanical testing.
• Preparation and evaluation of plant soft capsules using the dropping method.

Main Results:

• κ-carrageenan (κ-C) demonstrated strong interactions with CMS and SA, significantly improving capsule shell mechanical properties.
• A CMS/SA/κ-C ratio of 2:0.5:1.5 yielded dense, uniform films with optimal mechanical and adhesion properties.
• The novel plant soft capsules met enteric requirements, degraded completely within 15 minutes in simulated intestinal fluid, and outperformed gelatin capsules.

Conclusions:

• The optimized blend of SA, CMS, and κ-C provides a viable matrix for plant-based soft capsules.
• This formulation offers superior mechanical and degradation characteristics compared to traditional gelatin soft capsules.
• The study presents a promising alternative for the production of enteric soft capsules.