Sodium alginate/gelatin/guar gum oral delivery ternary composite hydrogel beads loaded with Anzhong decoction: Gastric floating retention and controlled release

The half-life of the traditional Chinese medicine Anzhong Decoction (AZD) is relatively short. When administered orally, insufficient retention in the stomach and rapid clearance rates result in significantly reduced drug utilization efficiency. To address this limitation, we developed ternary composite sodium alginate/gelatin/guar gum hydrogel beads (SA/Gel/GG HBs) using ion-gelation technology. Research revealed that guar gum (GG) incorporation enhances hydrogen bonding and network heterogeneity, as confirmed by ATR-FTIR and rheological analysis. Specifically, the formulation containing 0.4% GG (SA/Gel/4GG) achieved an optimal balance of properties. It demonstrated an encapsulation efficiency of 76.09%, a loading capacity of 7.02% and a high-water retention of 85.24%. Crucially, SA/Gel/4GG sustained gastric flotation for over 6 h with a flotation rate exceeding 95.04%. This was attributed to its low-density closed-cell structure, featuring a density of 0.36 g/cm 3 and porosity of 17.10%. The optimized microsphere exhibited a first-order kinetic release mechanism with biphasic release characteristics. Within 6 h, 79.21% of AZD was released into gastric fluid, followed by sustained release in the intestine. The antioxidant activity of AZD against DPPH and ABTS was well preserved. This SA/Gel/GG system presents a promising gastric-floating oral delivery platform for traditional Chinese medicine compounds, effectively extending gastric retention and enabling controlled drug release.