Optimizing fabrication of pharmaceutical capsule shell: a factorial design of corncob-MCC/Carrageenan/starch biofilm

Abstract

This study develops biodegradable soft-capsule films using carrageenan, tapioca starch, glycerol, and microcrystalline cellulose (MCC) derived from corncob waste as a halal- and vegetarian-friendly alternative to gelatin. A 2³ factorial design evaluated the effects of carrageenan (15–25 wt%), MCC (5–15 wt%), and glycerol (10–20 wt%) on tensile strength (TS), elongation (EL), and Young’s modulus (YM). The produced biofilms were characterized using mechanical testing, FTIR, XRD, SEM, TGA, disintegration tests, and ANOVA. Mechanical performance varied widely among samples. Among the synthesized biofilms, Sample 2 exhibited the highest tensile strength (6.565 MPa) and Young’s modulus (97.029 MPa), while Sample 5 showed the greatest ductility and dissolution time, reaching approximately 20% and 12 minutes, respectively, indicating rapid water-induced matrix breakdown associated with the hygroscopic nature of the polysaccharide-based system. Regression models were highly reliable, with R² values of 94.02%, 97.96%, and 96.78% for TS, EL, and YM, respectively. XRD confirmed MCC crystallinity of 62.6%. The TGA results confirm the films’ thermal stability and show moisture uptake and char residue consistent with the other analyses. Overall, the carrageenan–starch–MCC-glycerol system offers tunable properties, although further optimization is required for moisture control and purity.