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Updated: Jun 24, 2026

Preparation of Cross-Linked Sodium Alginate Microspheres with Different Metal Ions Using the Microfluidic Electrospray Technology
Published on: June 7, 2024
pH-sensitive hydrogel beads of β-cyclodextrin ionic liquid/methacrylated chitosan/alginate for enhancing loading and
Bahar Azad1, Zahra Mohamadnia2, Ebrahim Ahmadi1
1Department of Chemistry, Faculty of Science, University of Zanjan, P.O. Box 45195-313, Zanjan, Iran.
Abstract:
This study reports the fabrication of pH-sensitive hydrogel beads composed of β-cyclodextrin-ionic liquid/chitosan modified with glycidyl methacrylate/sodium alginate (CD-IL/CTS-GMA/Alg), cross-linked by calcium chloride (CaCl2) to improve the loading and delivery of poorly soluble drug amlodipine (AML). Chitosan was first modified with glycidyl methacrylate to obtain CTS-GMA, while CD-IL was synthesized by reacting mono-6-(p-toluenesulfonyl)-6-deoxy-cyclodextrin (CD-OTs) with vinyl imidazole. An aqueous solution of alginate containing AML was mixed with CD-IL/CTS-GMA copolymer, and the final solution was added dropwise into CaCl2 (3%) to form hydrogel beads at room temperature via the "egg-box" gelation model. Structural and morphological characterization was performed using FTIR, 1H NMR, and SEM. The CD-IL/CTS-GMA/Alg beads exhibited significantly enhanced AML loading efficiency (∼99%) compared to Alg/CTS beads (∼67%). The β-cyclodextrin moiety facilitated inclusion complexation with AML, improving solubility and stability, while the ionic liquid component further enhanced drug incorporation. Electrostatic interactions between alginate and chitosan imparted pH sensitivity. Drug release was limited under acidic conditions (pH 1.2, ∼20% after 96 h) but markedly higher under near-neutral conditions (pH 7.4, ∼86% after 96 h), demonstrating controlled and pH-dependent release. Cytotoxicity assays confirmed biocompatibility across 10-1000 μM. Overall, CD-IL/CTS-GMA/Alg hydrogel beads show strong potential as effective carriers for hydrophobic drugs.
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