Ionic Diffusion and Drug Release Behavior of Core-Shell-Functionalized Alginate-Chitosan-Based Hydrogel.

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Microfluidics

Background:

• Calcium alginate (CaALG) microbeads exhibit core-shell structures influenced by water levels, pH, and electrical conductivity.
• Developing effective drug delivery systems requires understanding material properties and controlled release mechanisms.

Purpose of the Study:

• To investigate the core-shell structure effects in CaALG microbeads concerning pH and electrical conductivity.
• To develop and test a novel microfluidic device for programmed drug release of risedronate (RIS) from CaALG-chitosan (CHT) microbeads.
• To evaluate the pH-responsive and gastro-protective properties of CaALG-CHT microbeads for RIS delivery.

Main Methods:

• Fabrication of CaALG microbeads with varying CaCl2 concentrations.
• Characterization of microbead swelling, pH, and electrical conductivity.
• Utilized a custom microfluidic device with a steplike barrier for single microbead analysis.
• Quantified RIS release using spectrophotometry at different pH levels (2.1, 4, 6.8, 7.4).

Main Results:

• Decreased CaCl2 concentration enhanced CaALG microbead swelling.
• Electrical current-voltage characteristics revealed pH-dependent ionic mobility and electrokinetic forces.
• CaALG-CHT microbeads demonstrated sustained RIS release and resistance to acidic environments.
• The microfluidic device enabled precise monitoring of drug release from individual microbeads.

Conclusions:

• CaALG-CHT microbeads offer a promising platform for sustained and pH-responsive delivery of risedronate.
• The developed microbeads can protect RIS from degradation in the stomach, potentially improving therapeutic outcomes and reducing gastric side effects.
• The novel microfluidic device is suitable for screening drugs and evaluating novel delivery systems.