Fabrication of hybrid alginate hydrogel beads reinforced with activated carbon and evaluation of their potential for controlled eugenol release

Abstract

Background/Objectives: This study presents the development of an activated carbon/sodium alginate-based gastric-retentive delivery system aimed at enhancing the gastroprotective efficacy of eugenol (Eug) in simulated body fluids. Methods: Hybrid hydrogel beads were fabricated using tea waste-derived activated carbon (AC) as a core material and sodium alginate as a wall material. Results: The system achieved a loading capacity of 3.37 ± 0.11 mg Eug/g hydrogel beads, and in vitro assays revealed a controlled release profile, with cumulative release reaching 0.694 ± 0.006 mg/g hydrogel beads in simulated gastric fluid (SGF) and 0.198 ± 0.002 mg Eug/g hydrogel beads in simulated intestinal fluid (SIF). Conclusions: Kinetic modeling confirmed a predominantly diffusion-controlled process with non-Fickian transport mechanism, indicating combined diffusion and matrix relaxation. By maintaining local therapeutic concentrations in the gastric mucosa, this pH-responsive Alg/Eug@AC system offers a sustainable strategy to overcome Eug’s low bioavailability and provide effective gastroprotection against oxidative damage.