Development, optimization, and characterization of microbially triggered <i>Mimosa pudica</i> gum–chitosan polyelectrolyte complex for colon-targeted drug delivery

This study aimed to develop a novel polymeric complex composed of <i>Mimosa pudica</i> gum (MMG) and chitosan (CH) and to explore its potential as a delivery system for targeting drugs to the colon. The method of extraction of MMG was optimized, resulting in a maximum yield of 12.41%. The molecular weight of the gum was determined to be 5.07 × 10⁶ Da, and it was characterized for its physicochemical and rheological properties. A species distribution profile was constructed using the pKa values of both polymers, and polyelectrolyte complexes (PECs) were prepared at a pH value of 5.25 ± 0.10. The 40:60 (MMG: CH) PECs exhibited the highest yield (99%), minimal viscosity, and near-neutral zeta potential. Microflora biodegradation studies of PECs in pH 6.8 buffer containing rat cecal contents showed a pH decrease, likely due to degradation products of the PECs. <i>In vitro</i> drug release studies revealed 16.6% capecitabine release (model drug) from PECs without rat cecal contents, compared to 88.5% release after 24h with rat cecal contents. These findings suggest that MMG-CH PECs could serve as promising vehicles for microbially triggered, colon-targeted drug delivery systems.