Design and assessment of highly stable norfloxacin/ Ca-montmorillonite (STx-1b) as oral beads

This study utilized sodium alginate (SA), known for its ability to selectively cross-link with certain divalent cations to form ionic gels, making it an ideal carrier for gel materials. In this study, we employed non-toxic Ca-montmorillonite (STx-1b) as the foundational material and mixed it with SA to produce composite beads containing norfloxacin (NF) for use as oral beads. After evaluating the available concentrations of NF in the market, we selected the lowest concentration of 115 mg g ⁻¹ for our antibacterial efficacy tests, which were conducted as a series of batch studies. Before these experiments, we confirmed that the composite beads successfully encapsulated NF during an 8-h loading period and optimized various parameters including bead stability, the amount and time of NF loading, and desorption rates. Notably, only 10% of the drug was desorbed under acidic conditions (pH 2, simulating gastric juice), indicating minimal loss of NF before reaching the intestinal tract, with the beads exhibiting no disintegration. The composite beads demonstrated significant antibacterial efficacy against Escherichia coli ( E. coli), highlighting their potential as competitive alternatives in the field of oral drug delivery. Furthermore, scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA) were utilized to characterize the composite beads. For the disposal of expired beads, TGA results indicated that heating the beads to 350 °C would facilitate their disintegration, thereby minimizing environmental impact. Consequently, the composite beads composed of SA and STx-1b are suitable for use as oral beads.