Amidated xanthan gum-coated gastroretentive beads for controlled release of chebulinic acid solid dispersions.

This study investigates the usefulness of chemically modified xanthan gum (XG), a natural polysaccharide known for its mucoadhesive and swelling characteristics, in gastroretentive drug delivery systems. XG was modified through amidation using triethanolamine in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) as a coupling agent. The resulting amidated xanthan gum (AXG) exhibited significantly improved physicochemical properties, including reduced hydrophilicity, enhanced thermal stability, and increased crystallinity, as confirmed by FTIR, DSC, XRD, and ^1H NMR analyses. Sodium alginate beads were prepared via the ionotropic gelation and subsequently coated with XG and AXG through diffusion-controlled interfacial complexation. The formulations demonstrated sustained drug release (74.8-93.1 %), low densities (0.524-0.40 g/cm3), minimal lag time (5.12-6.18 s), and high drug encapsulation efficiency (58.01-66.43 %). AXG-coated formulations exhibited a higher swelling index (161 %) compared to XG-coated formulations (119 %). SEM analysis revealed the presence of AXG fragments on the bead surfaces. Ex vivo studies confirmed superior mucoadhesive properties of AXG (58 %) compared to XG (46 %). In conclusion, AXG-based composites outperformed XG in achieving targeted and controlled drug delivery to the stomach.